Spitzer Finds Possible Exoplanet Smaller Than Earth

Astronomers using NASA's Spitzer Space Telescope have detected what they believe is an alien world just two-thirds the size of Earth - one of the smallest on record. The exoplanet candidate, known as UCF-1.01, orbits a star called GJ 436, which is located a mere 33 light-years away. UCF-1.01 might be the nearest world to our solar system that is smaller than our home planet. Credit: NASA/JPL-Caltech.

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PASADENA, Calif. -- Astronomers using NASA's Spitzer Space Telescope have detected what they believe is a planet two-thirds the size of Earth. The exoplanet candidate, called UCF-1.01, is located a mere 33 light-years away, making it possibly the nearest world to our solar system that is smaller than our home planet.

Exoplanets circle stars beyond our sun. Only a handful smaller than Earth have been found so far. Spitzer has performed transit studies on known exoplanets, but UCF-1.01 is the first ever identified with the space telescope, pointing to a possible role for Spitzer in helping discover potentially habitable, terrestrial-sized worlds.

"We have found strong evidence for a very small, very hot and very near planet with the help of the Spitzer Space Telescope," said Kevin Stevenson from the University of Central Florida in Orlando. Stevenson is lead author of the paper, which has been accepted for publication in The Astrophysical Journal. "Identifying nearby small planets such as UCF-1.01 may one day lead to their characterization using future instruments."

The hot, new-planet candidate was found unexpectedly in Spitzer observations. Stevenson and his colleagues were studying the Neptune-sized exoplanet GJ 436b, already known to exist around the red-dwarf star GJ 436. In the Spitzer data, the astronomers noticed slight dips in the amount of infrared light streaming from the star, separate from the dips caused by GJ 436b. A review of Spitzer archival data showed the dips were periodic, suggesting a second planet might be orbiting the star and blocking out a small fraction of the star's light.

This technique, used by a number of observatories including NASA's Kepler space telescope, relies on transits to detect exoplanets. The duration of a transit and the small decrease in the amount of light registered reveals basic properties of an exoplanet, such as its size and distance from its star. In UCF-1.01's case, its diameter would be approximately 5,200 miles (8,400 kilometers), or two-thirds that of Earth. UCF-1.01 would revolve quite tightly around GJ 436, at about seven times the distance of Earth from the moon, with its "year" lasting only 1.4 Earth days. Given this proximity to its star, far closer than the planet Mercury is to our sun, the exoplanet's surface temperature would be more than 1,000 degrees Fahrenheit (almost 600 degrees Celsius).

If the roasted, diminutive planet candidate ever had an atmosphere, it almost surely has evaporated. UCF-1.01 might therefore resemble a cratered, mostly geologically dead world like Mercury. Paper co-author Joseph Harrington, also of the University of Central Florida and principal investigator of the research, suggested another possibility; that the extreme heat of orbiting so close to GJ 436 has melted the exoplanet's surface.

"The planet could even be covered in magma," Harrington said.

In addition to UCF-1.01, Stevenson and his colleagues noticed hints of a third planet, dubbed UCF-1.02, orbiting GJ 436. Spitzer has observed evidence of the two new planets several times each. However, even the most sensitive instruments are unable to measure exoplanet masses as small as UCF-1.01 and UCF-1.02, which are perhaps only one-third the mass of Earth. Knowing the mass is required for confirming a discovery, so the paper authors are cautiously calling both bodies exoplanet candidates for now.

Of the approximately 1,800 stars identified by NASA' Kepler space telescope as candidates for having planetary systems, just three are verified to contain sub-Earth-sized exoplanets. Of these, only one exoplanet is thought to be smaller than the Spitzer candidates, with a radius similar to Mars, or 57 percent that of Earth.

"I hope future observations will confirm these exciting results, which show Spitzer may be able to discover exoplanets as small as Mars," said Michael Werner, Spitzer project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Even after almost nine years in space, Spitzer's observations continue to take us in new and important scientific directions."

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .

More information about exoplanets and NASA's planet-finding program is at http://planetquest.jpl.nasa.gov .

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

J.D. Harrington 202-358-5241
Headquarters, Washington
j.d.harrington@nasa.gov

NASA's Spitzer Finds Galaxy With Split Personality

The infrared vision of NASA's Spitzer Space Telescope has revealed that the Sombrero galaxy -- named after its appearance in visible light to a wide-brimmed hat -- is in fact two galaxies in one. Image credit: NASA/JPL-Caltech. Full image and caption

New observations from NASA's Spitzer Space Telescope reveal the Sombrero galaxy is not simply a regular flat disk galaxy of stars as previously believed, but a more round elliptical galaxy with a flat disk tucked inside. Full image and caption-enlarge image

PASADENA, Calif. -- While some galaxies are rotund and others are slender disks like our spiral Milky Way, new observations from NASA's Spitzer Space Telescope show that the Sombrero galaxy is both. The galaxy, which is a round elliptical galaxy with a thin disk embedded inside, is one of the first known to exhibit characteristics of the two different types. The findings will lead to a better understanding of galaxy evolution, a topic still poorly understood.

"The Sombrero is more complex than previously thought," said Dimitri Gadotti of the European Southern Observatory in Chile and lead author of a new paper on the findings appearing in the Monthly Notices of the Royal Astronomical Society. "The only way to understand all we know about this galaxy is to think of it as two galaxies, one inside the other."

The Sombrero galaxy, also known as NGC 4594, is located 28 million light-years away in the constellation Virgo. From our viewpoint on Earth, we can see the thin edge of its flat disk and a central bulge of stars, making it resemble a wide-brimmed hat. Astronomers do not know whether the Sombrero's disk is shaped like a ring or a spiral, but agree it belongs to the disk class.

"Spitzer is helping to unravel secrets behind an object that has been imaged thousands of times," said Sean Carey of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "It is intriguing Spitzer can read the fossil record of events that occurred billions of years ago within this beautiful and archetypal galaxy."

Spitzer captures a different view of the galaxy than visible-light telescopes. In visible views, the galaxy appears to be immersed in a glowing halo, which scientists had thought was relatively light and small. With Spitzer's infrared vision, a different view emerges. Spitzer sees old stars through the dust and reveals the halo has the right size and mass to be a giant elliptical galaxy.

While it is tempting to think the giant elliptical swallowed a spiral disk, astronomers say this is highly unlikely because that process would have destroyed the disk structure. Instead, one scenario they propose is that a giant elliptical galaxy was inundated with gas more than nine billion years ago. Early in the history of our universe, networks of gas clouds were common, and they sometimes fed growing galaxies, causing them to bulk up. The gas would have been pulled into the galaxy by gravity, falling into orbit around the center and spinning out into a flat disk. Stars would have formed from the gas in the disk.

"This poses all sorts of questions," said Rubén Sánchez-Janssen from the European Southern Observatory, co-author of the study. "How did such a large disk take shape and survive inside such a massive elliptical? How unusual is such a formation process?"

Researchers say the answers could help them piece together how other galaxies evolve. Another galaxy, called Centaurus A, appears also to be an elliptical galaxy with a disk inside it. But its disk does not contain many stars. Astronomers speculate that Centaurus A could be at an earlier stage of evolution than the Sombrero and might eventually look similar.

The findings also answer a mystery about the number of globular clusters in the Sombrero galaxy. Globular clusters are spherical nuggets of old stars. Ellipticals typically have a few thousand, while spirals contain a few hundred. The Sombrero has almost 2,000, a number that makes sense now but had puzzled astronomers when they thought it was only a disk galaxy.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

J.D. Harrington 202-358-0321
Headquarters, Washington
j.d.harrington@nasa.gov

Public to get access to spectacular infrared images of galaxies

Left: The mid-infrared (24 micron) image of M91 as seen with the Spitzer Space Telescope. M91 is the prototype example of a barred spiral galaxy. Although the spiral arms are easily seen in mid-infrared light, the bar is only faintly visible.

Right: NGC 4772 contains a dust ring that is bright in mid-infrared light. Dust rings like this are common in many spiral galaxies.

These galaxies is just two of the over 200 galaxies for which reprocessed Spitzer Space Telescope data are being released to the general public for the first time.

For the first time, the general public will be able to browse detailed infrared images of more than 200 galaxies. The pictures, originating from data from the orbiting Spitzer Space Telescope, are currently being released to the general public. Dr. George Bendo of the Jodrell Bank Centre for Astrophysics will highlight the new imagery at the National Astronomy Meeting in Manchester from 27-30 March.

The pictures are mid-infrared (24 micron wavelength) reprocessed images of nearby galaxies observed with Spitzer between 2003 and 2009. Amongst the images are the objects M60, M61, M88, M91 and M98, all of which lie between 47 and 63 million light years away in the large cluster of galaxies found in the direction of the constellation of Virgo.

The mid-infrared light from these galaxies primarily traces interstellar dust heated by the hot young stars found in the places where stars are forming. These images, which are being made available to the public for the first time, are a small sample of those that will be released later in the year.

Dr. Bendo explains how complicated it was to make the data usable for science. "The 24-160 micron Spitzer images need expert processing to be suitable for scientists, let alone the general public and until now many of them had been overlooked. I volunteered to do this work for these galaxies as they will soon be observed by the Herschel Space Observatory at far-infrared wavelengths." With processed Spizter data, astronomers will be able to make a direct comparison between the views from each telescope.

He is delighted to be bringing the Spitzer material to the public: "These data show the intimate connection between the interstellar dust in galaxies, here seen shining in infrared light, and the formation of stars on a grand scale. Now anyone with internet access can download these extraordinary pictures for themselves and take a look at some of the objects being studied by the world's leading astronomers, as part of their effort to better understand the universe we live in."

Example images

The mid-infrared (24 micron) images below are a sample of the over 200 galaxy images that are being released to the general public. Click on any link below to see the full-sized version of the image.

Left: M60 is actually two galaxies that appear next to each other in the sky but are actually physically separated from each other. The larger elliptical galaxy looks relatively faint and contains little dust to produce mid-infrared light, but the smaller spiral galaxy contains a lot of dust and looks much brighter.

Center: M61 is one of the larger spiral galaxies in the Virgo Cluster. The spiral arms and the nucleus in this galaxy are both locations where many hot young stars are forming. These stars heat up the interstellar dust that looks very bright in mid-infrared light.

Right: M88 is currently underoing a process where the interstellar gas and dust in the galaxy are colliding with gas between the galaxies in the Virgo Cluster. This process will eventually strip away much of the gas and dust in the galaxy.

Left: M98 contains a structure that looks like a dust ring. While these dust rings may be common in spiral galaxies, they can be difficult to spot in visible light.

Center: NGC 891 is a spiral galaxy that we see edge-on from Earth. In visible light, we see a dark dust lane across the disc of the galaxy where the interstellar dust abosrbs starlight, but in infrared images like this one, we see that energy re-radiated in infrared light.

Right: NGC 4698 is another spiral galaxy with a very well-defined dust ring. The centre of the galaxy contains an active galactic nucleus. Astronomers hypothesize that such active galactic nuclei contain supermassive black holes. While the black hole itself would produce no light, the region around the black hole can very very bright and could be producing the infrared light seen from the centre of this galaxy.

Left: NGC 3953 contains a very small bar in its centre that looks like a thin slash in this mid-infrared image. Bars like this one can transfer gas and dust (like the dust we see in this mid-infrared image) into the centres of galaxies.

Center: NGC 4298 and NGC 4302 both appear close to each other in sky but are actually further apart than implied by this image. Both of these galaxies are located in the Virgo Cluster and are falling towards the centre of the cluster.

Right: NGC 4565 is an edge-on spiral galaxy. In visible light, we would see a bright bulge in the centre of this galaxy, but the bulge is virtually invisible in mid-infrared light. We would also see the interstellar dust in the disc appear as a dark cloud across this galaxy, but that dust appears like a narrow edge-on disc in mid-infrared light.

Editors notes:
Further information

The scientific data are available from:
http://hedam.oamp.fr/
http://www.jb.man.ac.uk/~gbendo/exchange/SpitzerData/spitzerdata_main.html

For more information, please see:
http://www.spitzer.caltech.edu/
http://coolcosmos.ipac.caltech.edu/

Contacts

For more information please contact

Dr. George Bendo
Jodrell Bank Centre for Astrophysics
University of Manchester
United Kingdom
Tel: +44 (0)161 27 54258
Mob: +44 (0)77 2250 3332
Email: george.bendo@manchester.ac.uk

NAM 2012 Press Office 0900 - 1730 GMT, 27-29 April; 0900 - 1630 GMT 30 April)
Room 3.214
University Place building
University of Manchester
Manchester
UK
Tel: +44 (0)161 306 7313

Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)794 124 8035
Email: rm@ras.org.uk

Anita Heward
Royal Astronomical Society
Mob: +44 (0)7756 034 243
Email: anitaheward@btinternet.com

Dr Klaus Jaeger
Pressereferent / Press Officer im Vorstand der Astronomischen Gesellschaft
Tel: +49 6221 528 379
Email: pressereferent@astronomische-gesellschaft.de

Dan Cochlin
Media Officer (Faculty of Engineering and Physical Sciences)
University of Manchester
Tel: +44 (0)161 275 8387
Email: daniel.cochlin@manchester.ac.uk

NAM 2012

Bringing together more than 900 astronomers and space scientists, the National Astronomy Meeting (NAM 2012) will take place from 27-30 March 2012 in the University Place conference centre at the University of Manchester in the UK. The conference is a joint meeting of the Royal Astronomical Society (RAS) and the German Astronomische Gesellschaft (AG) and is held in conjunction with the UK Solar Physics (UKSP: www.uksolphys.org) and Magnetosphere Ionosphere Solar Terrestrial (MIST: www.mist.ac.uk) meetings. NAM 2012 is principally sponsored by the RAS, AG, STFC and the University of Manchester.

The Royal Astronomical Society

The Royal Astronomical Society (RAS: www.ras.org.uk), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organises scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 3500 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The Astronomische Gesellschaft (AG)

The Astronomische Gesellschaft (AG: www.astronomische-gesellschaft.de), founded in 1863, is a modern astronomical society with more than 800 members dedicated to the advancement of astronomy and astrophysics and the networking between astronomers. It represents German astronomers, organises scientific meetings, publishes journals, offers grants, recognises outstanding work through awards and places a high priority on the support of talented young scientists, public outreach and astronomy education in schools.

The Science and Technology Facilities Council

The Science and Technology Facilities Council (STFC: www.stfc.ac.uk) is keeping the UK at the forefront of international science and tackling some of the most significant challenges facing society such as meeting our future energy needs, monitoring and understanding climate change, and global security. The Council has a broad science portfolio and works with the academic and industrial communities to share its expertise in materials science, space and ground-based astronomy technologies, laser science, microelectronics, wafer scale manufacturing, particle and nuclear physics, alternative energy production, radio communications and radar. It enables UK researchers to access leading international science facilities for example in the area of astronomy, the European Southern Observatory.

Jodrell Bank Centre for Astrophysics

The Jodrell Bank Centre for Astrophysics (JBCA: www.jb.man.ac.uk/) is part of the School of Physics & Astronomy at the University of Manchester. JBCA is split over two main sites: the Alan Turing Building in Manchester and the Jodrell Bank Observatory in Cheshire. At Jodrell Bank Observatory, the new Jodrell Bank Discovery Centre is a key focus for our work in public engagement and education. Jodrell Bank is a world leader in radio astronomy-related research and technology development with a research programme extending across much of modern astrophysics. The group operates the e-MERLIN national radio astronomy facility and the iconic Lovell Telescope, hosts the UK ALMA Regional Centre Node and is home to the international office of the SKA Organisation. Funded by the University, the Science & Technology Facilities Council and the European Commission, it is one of the UK's largest astrophysics research groups.

NASA's Spitzer Finds Solid Buckyballs in Space

NASA's Spitzer Space Telescope has detected the solid form of buckyballs in space for the first time. To form a solid particle, the buckyballs must stack together, as illustrated in this artist's concept showing the very beginnings of the process. Image credit: NASA/JPL-Caltech. Full image and caption

NASA's Spitzer Space Telescope has detected the solid form of buckyballs in space for the first time. To form a solid particle, the buckyballs must stack together like oranges in a crate, as shown in this illustration. Image credit: NASA/JPL-Caltech. Larger image

PASADENA, Calif. -- Astronomers using data from NASA's Spitzer Space Telescope have, for the first time, discovered buckyballs in a solid form in space. Prior to this discovery, the microscopic carbon spheres had been found only in gas form in the cosmos.

Formally named buckministerfullerene, buckyballs are named after their resemblance to the late architect Buckminster Fuller's geodesic domes. They are made up of 60 carbon molecules arranged into a hollow sphere, like a soccer ball. Their unusual structure makes them ideal candidates for electrical and chemical applications on Earth, including superconducting materials, medicines, water purification and armor.

In the latest discovery, scientists using Spitzer detected tiny specks of matter, or particles, consisting of stacked buckyballs. They found the particles around a pair of stars called "XX Ophiuchi," 6,500 light-years from Earth, and detected enough to fill the equivalent in volume to 10,000 Mount Everests.

"These buckyballs are stacked together to form a solid, like oranges in a crate," said Nye Evans of Keele University in England, lead author of a paper appearing in the Monthly Notices of the Royal Astronomical Society. "The particles we detected are miniscule, far smaller than the width of a hair, but each one would contain stacks of millions of buckyballs."

Buckyballs were detected definitively in space for the first time by Spitzer in 2010. Spitzer later identified the molecules in a host of different cosmic environments. It even found them in staggering quantities, the equivalent in mass to 15 Earth moons, in a nearby galaxy called the Small Magellanic Cloud.

In all of those cases, the molecules were in the form of gas. The recent discovery of buckyballs particles means that large quantities of these molecules must be present in some stellar environments in order to link up and form solid particles. The research team was able to identify the solid form of buckyballs in the Spitzer data because they emit light in a unique way that differs from the gaseous form.

"This exciting result suggests that buckyballs are even more widespread in space than the earlier Spitzer results showed," said Mike Werner, project scientist for Spitzer at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "They may be an important form of carbon, an essential building block for life, throughout the cosmos."

Buckyballs have been found on Earth in various forms. They form as a gas from burning candles and exist as solids in certain types of rock, such as the mineral shungite found in Russia, and fulgurite, a glassy rock from Colorado that forms when lightning strikes the ground. In a test tube, the solids take on the form of dark, brown "goo."

"The window Spitzer provides into the infrared universe has revealed beautiful structure on a cosmic scale," said Bill Danchi, Spitzer program scientist at NASA Headquarters in Washington. "In yet another surprise discovery from the mission, we're lucky enough to see elegant structure at one of the smallest scales, teaching us about the internal architecture of existence."

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

For information about previous Spitzer discoveries of buckyballs, visit hand http://www.nasa.gov/mission_pages/spitzer/news/spitzer20101027.html .

For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

Trent J. Perrotto 202-358-0321
NASA Headquarters, Washington
trent.j.perrotto@nasa.gov

NASA's Spitzer Detects Comet Storm in Nearby Solar System

This artist's conception illustrates a storm of comets around a star near our own, called Eta Corvi. Evidence for this barrage comes from NASA's Spitzer Space Telescope, whose infrared detectors picked up indications that one or more comets was recently torn to shreds after colliding with a rocky body. Image credit: NASA/JPL-Caltech . Full image and caption

PASADENA, Calif. -- NASA's Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the "Late Heavy Bombardment," which may have brought water and other life-forming ingredients to Earth.

During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.

Now Spitzer has spotted a band of dust around a nearby bright star in the northern sky called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close enough to Eta Corvi that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.

"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system," said Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and lead author of a paper detailing the findings. The findings will be published in the Astrophysical Journal. Lisse presented the results at the Signposts of Planets meeting at NASA's Goddard Space Flight Center in Greenbelt, Md., today, Oct. 19.

Astronomers used Spitzer's infrared detectors to analyze the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.

The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective solar systems.

A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, looms at about 150 times the distance from Eta Corvi as the Earth is from the sun. Our solar system has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt.

The Kuiper Belt was home to a vastly greater number of these frozen bodies, collectively dubbed Kuiper Belt objects. About 4 billion years ago, some 600 million years after our solar system formed, scientists think the Kuiper Belt was disturbed by a migration of the gas-giant planets Jupiter and Saturn. This jarring shift in the solar system's gravitational balance scattered the icy bodies in the Kuiper Belt, flinging the vast majority into interstellar space and producing cold dust in the belt. Some Kuiper Belt objects, however, were set on paths that crossed the orbits of the inner planets.

The resulting bombardment of comets lasted until 3.8 billion years ago. After comets impacted the side of the moon that faces Earth, magma seeped out of the lunar crust, eventually cooling into dark "seas," or maria. When viewed against the lighter surrounding areas of the lunar surface, those seas form the distinctive "Man in the Moon" visage. Comets also struck Earth or incinerated in the atmosphere, and are thought to have deposited water and carbon on our planet. This period of impacts might have helped life form by delivering its crucial ingredients.

"We think the Eta Corvi system should be studied in detail to learn more about the rain of impacting comets and other objects that may have started life on our own planet," Lisse said.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer mission for the agency's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

For more information about Spitzer, visit: http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

Trent J. Perrotto 202-358-0321
Headquarters, Washington
trent.j.perrotto@nasa.gov

Spitzer Detects a Steaming Super-Earth Eclipsing Its Star

55 Cancri e
Credit: NASA/JPL-Caltech/R. Hurt (SSC)

NASA's Spitzer Space Telescope has gathered surprising new details about a supersized and superheated version of Earth called 55 Cancri e. According to Spitzer data, the exoplanet is less dense than previously thought, a finding which profoundly changes the portrait of this exotic world. Instead of a dense rock scorched dry by its sun, 55 Cancri e likely has water vapor and other gases steaming from its molten surface.

Spitzer measured the extraordinarily small amount of light 55 Cancri e blocked when the planet crossed in front of its star. These mini-eclipses, called transits, allow astronomers to accurately determine a planet's size and calculate its density. Promisingly, the results show how astronomers can use Spitzer, operating in "warm" mode since depleting its liquid coolant in May 2009, to probe the properties of strange alien worlds.

"This work demonstrates that 'warm' Spitzer can measure an extremely faint eclipse caused by exoplanets' transits with very high precision," said Brice-Olivier Demory, a post-doctoral associate in Professor Sara Seager's group in the Earth, Atmospheric and Planetary Sciences department at the Massachusetts Institute of Technology (MIT). Demory, who is lead author of a paper accepted for publication in Astronomy & Astrophysics, said that the study "emphasizes the important role Spitzer still has to play for the detection and characterization of transiting planets."

Blazing Hot and on the Move

Astronomers first discovered 55 Cancri e in 2004, and continued investigation of the exoplanet has shown it to be a truly bizarre place. The world revolves around its sunlike star in the shortest time period of all known exoplanets - just 17 hours and 40 minutes. (In other words, a year on 55 Cancri e lasts less than 18 hours.) The exoplanet orbits about 26 times closer to its star than Mercury, the most Sun-kissed planet in our solar system. Such proximity means that 55 Cancri e's surface roasts at a minimum of 3,200 degrees Fahrenheit (1,760 degrees Celsius).

The new observations with Spitzer reveal 55 Cancri e to have a mass 7.8 times and a radius just over twice that of Earth. Those properties place 55 Cancri e in the "super-Earth" class of exoplanets, a few dozen of which have been found. Only a handful of known super-Earths, however, cross the face of their stars as viewed from our vantage point in the cosmos. At just 40 light years away, 55 Cancri e stands as the smallest transiting super-Earth in our stellar neighborhood. In fact, 55 Cancri is so bright and close that it can be seen with the naked eye on a clear, dark night.

Based on the precise Spitzer data, Demory and his colleagues came up with a revised, lower density for 55 Cancri e. Coupled with its tight orbit, 55 Cancri e possesses a unique combination of super-Earth traits. Its low density is similar to that of a cooler super-Earth called GJ1214b, discovered in 2009 orbiting a tiny, dim star. Yet 55 Cancri e's orbit is more like that of the denser, inferno worlds CoRoT-7b and Kepler-10b. "What makes 55 Cancri e so remarkable is that despite its high temperature, the planet has a low density," said Demory.

Previously, a separate international team of astronomers had made observations of 55 Cancri e in visible light with Canada's MOST telescope. Initially, their evidence implied that 55 Cancri e's diameter was smaller by 25 percent, leading to reports of 55 Cancri e as actually the densest planet known. Refinements to those observations, however, now agree with the new Spitzer findings, which rely on a transit seen in longer-wavelength infrared light.

Exoplanetary Origins and Future Demise

No longer looking like a dense planet of solid rock, 55 Cancri e instead appears to be an unprecedented world with an intriguing history. The Spitzer results suggest that about a fifth of the planet's mass must be made of light elements and compounds, including water. In the intense heat of 55 Cancri e's terribly close sun, those light materials would exist in a "supercritical" state, between that of a liquid and a gas, and might sizzle out of the planet's surface.

New developments in planetary formation and evolution theory will probably be necessary to explain 55 Cancri e's back story. According to our models of the birth of solar systems, for example, 55 Cancri e could not have formed so near its star. Maybe it started out as a more distant planet with a large gaseous atmosphere. As worlds took shape in the 55 Cancri solar system, gravitational interactions amongst the system's five known planets could have prodded a young 55 Cancri e to migrate in toward its sun. In the process, the Neptune-like exoplanet might have lost most of its atmosphere, exposing a core that sputters with the venting of heated chemicals.

It seems certain that 55 Cancri e is on a "death spiral," soon to be devoured or ripped apart by its host star. But for now, the world's serendipitous placement in our sky will allow Spitzer and other instruments to study 55 Cancri e in further detail, expanding our knowledge of how exoplanets work.

"55 Cancri e orbits a very bright star thus enabling the possibility of obtaining a wealth of observations with space-based facilities at various wavelengths," said study co-author Michael Gillon of the University of Liege in Belgium and principal investigator for the warm Spitzer program aimed at detecting transiting low-mass exoplanets. "This fact will make 55 Cancri e a landmark for our understanding of the planetary interior and atmospheric composition of super-Earths."

Other authors of the paper are Diana Valencia, Sara Seager and Bjorn Benneke of MIT; Drake Deming of the University of Maryland; Christophe Lovis, Michel Mayor, Francesco Pepe, Didier Queloz, Damien Ségransan, and Stéphane Udry of the University of Geneva; and Patricio Cubillos, Joseph Harrington, and Kevin B. Stevenson of the University of Central Florida.

Source: Spitzer Space Telescope

Spitzer Sees Spider Web of Stars

IC 342's dust structures show up vividly in red, in this infrared view from Spitzer. Image credit: NASA/JPL-Caltech. Full image and caption

IC 342 has a lower density of stars than what is typical for galaxies, as indicated by a very faint blue haze coming from starlight. Image credit: NASA/JPL-Caltech. Full image and caption

Those aren't insects trapped in a spider's web -- they're stars in our own Milky Way galaxy, lying between us and another spiral galaxy called IC 342. NASA's Spitzer Space Telescope captured this picture in infrared light, revealing the galaxy's bright patterns of dust.

At a distance of about 10 million light-years from Earth, IC 342 is relatively close by galaxy standards. However, our vantage point places it directly behind the disk of our own Milky Way. The intervening dust makes it difficult to see in visible light, but infrared light penetrates this veil easily. While stars in our own galaxy appear as blue/white dots, the blue haze is from IC 342's collective starlight. Red shows the dust structures, which contain clumps of new stars.

The center of the galaxy, where one might look for a spider, is actually home to an enormous burst of star formation. To either side of the center, a small bar of dust and gas is helping to fuel the new stars.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer

Whitney Clavin (818) 354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

Kepler-10 Stellar Family Portrait

Kepler-10 star ystem

Credit: NASA/Ames/JPL-Caltech/T. Pyle

This artist's conception depicts the Kepler-10 star system, located about 560 light-years away near the Cygnus and Lyra constellations. Kepler has discovered two planets around this star. Kepler-10b is, to date, the smallest known rocky exoplanet, or planet outside our solar system (dark spot against yellow sun). This planet, which has a radius of 1.4 times that of Earth's, whips around its star every .8 days. Its discovery was announced in Jan. 2011.

Now, in May 2011, the Kepler team is announcing another member of the Kepler-10 family, called Kepler-10c (larger foreground object). It's bigger than Kepler-10b with a radius of 2.2 times that of Earth's, and it orbits the star every 45 days. Both planets would be blistering hot worlds.

Kepler-10c was first identified by Kepler, and later validated using a combination of a computer simulation technique called "Blender," and NASA's Spitzer Space Telescope. Both of these methods are powerful ways to validate the Kepler planets that are too small and faraway for ground-based telescopes to confirm using the radial-velocity technique. The Kepler team says that a large fraction of their discoveries will be validated with both of these methods.

In the case of Kepler-10c, scientists can be 99.998 percent sure that the signal they detected is from an orbiting planet. Part of this confidence comes from the fact that Spitzer, an infrared observatory, saw a signal similar to what Kepler detected in visible light. If the signal were coming from something other than an orbiting planet -- for example an indistinguishable background pair of orbiting stars -- then scientists would expect to see different signals in visible and infrared light.

Source: NASA's Spitzer Space Telescope

NASA's Spitzer Discovers Time-Delayed Jets Around Young Star

This image layout shows two views of the same baby star -- at left is a visible-light image, and at right is an infrared image from NASA's Spitzer Space Telescope. Image credit: NASA/JPL-Caltech. Full image and caption

NASA's Spitzer Space Telescope took this image of a baby star sprouting two identical jets (green lines emanating from fuzzy star. Image credit: NASA/JPL-Caltech. Full image and caption

Astronomers have discovered that two symmetrical jets shooting away from opposite sides of a blossoming star are experiencing a time delay: knots of gas and dust from one jet blast off four-and-a-half years later than identical knots from the other jet.

The finding, which required the infrared vision of NASA's Spitzer Space Telescope, is helping astronomers understand how jets are produced around forming stars, including those resembling our sun when it was young.

"More studies are needed to determine if other jets have time delays," said Alberto Noriega-Crespo of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena, who is a co-author of the new study to be published in the April 1 issue of Astrophysical Journal Letters. "Now we know that in at least one case, there appears to be a delay, which tells us that some sort of communication may be going on between the jets that takes time to occur."

Jets are an active phase in a young star's life. A star begins as a collapsing, roundish cloud of gas and dust. By ejecting supersonic jets of gas, the cloud slows down its spinning. As material falls onto the growing star, it develops a surrounding disk of swirling material and twin jets that shoot off from above and below the disk, like a spinning top.

Once the star ignites and shines with starlight, the jets will die off and the disk will thin out. Ultimately, planets may clump together out of material left in the spinning disk.

The discovery of the time delay, in the jets called Herbig-Haro 34, has also led the astronomers to narrow in on the size of the zone from which the jets originate. The new Spitzer observations limit this zone to a circle around the young star with a radius of 3 astronomical units. An astronomical unit is the distance between our sun and Earth. This is about 10 times smaller than previous estimates.

"Where we stand today on Earth was perhaps once a very violent place where high-velocity gas and dust were ejected from the disk circling around our very young sun," said Alex Raga of the Universidad Nacional Autónoma de México, the first author of the paper. "If so, the formation of planets like Earth depends on how and when this phenomenon ended. Essentially, every star like our own sun has gone through a similar cloud-disk-jets formation process."

One of the jets in Herbig-Haro 34 had been studied extensively for years, but the other remained hidden behind a dark cloud. Spitzer's sensitive infrared vision was able to pierce this cloud, revealing the obscured jet in greater detail than ever before. Spitzer images show that the newfound jet is perfectly symmetrical to its twin, with identical knots of ejected material.

This symmetry turned out to be key to the discovery of the jets' time delay. By measuring the exact distances from the knots to the star, the astronomy team was able to figure out that, for every knot of material punched out by one jet, a similar knot is shot out in the opposite direction 4.5 years later. This calculation also depended on the speed of the jets, which was known from previous studies by NASA's Hubble Space Telescope. Other symmetrical jets similar to Herbig-Haro 34 have been observed closely before, but it is not clear if they are also experiencing time delays.

The astronomers say that some kind of communication is going on between the Herbig-Haro 34 jets, likely carried by sound waves. Knowing the length of the time delay and the speed of sound allowed them to calculate the maximum size of the jet-making zone.

The astronomy team is currently analyzing other jets imaged by Spitzer, looking for more evidence of time delays.

The Spitzer observations were made before it used up its liquid coolant in May 2009 and began its warm mission.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

New View of Family Life in the North American Nebula

North American Nebula

Credit: NASA/JPL-Caltech/L. Rebull (SSC/Caltech)

Pasadena, Calif. -- Stars at all stages of development, from dusty little tots to young adults, are on display in a new image from NASA's Spitzer Space Telescope.

This cosmic community is called the North American nebula. In visible light, the region resembles the North American continent, with the most striking resemblance being the Gulf of Mexico. But in Spitzer's infrared view, the continent disappears. Instead, a swirling landscape of dust and young stars comes into view.

"One of the things that makes me so excited about this image is how different it is from the visible image, and how much more we can see in the infrared than in the visible," said Luisa Rebull of NASA's Spitzer Science Center at the California Institute of Technology, Pasadena, Calif. Rebull is lead author of a paper about the observations, accepted for publication in the Astrophysical Journal Supplement Series. "The Spitzer image reveals a wealth of detail about the dust and the young stars here."

Rebull and her team have identified more than 2,000 new, candidate young stars in the region. There were only about 200 known before. Because young stars grow up surrounded by blankets of dust, they are hidden in visible-light images. Spitzer's infrared detectors pick up the glow of the dusty, buried stars.

A star is born inside a collapsing ball of gas and dust. As the material collapses inward, it flattens out into a disk that spins around together with the forming star like a spinning top. Jets of gas shoot perpendicularly away from the disk, above and below it. As the star ages, planets are thought to form out of the disk -- material clumps together, ultimately growing into mature planets. Eventually, most of the dust dissipates, aside from a tenuous ring similar to the one in our solar system, referred to as Zodiacal dust.

The new Spitzer image reveals all the stages of a star's young life, from the early years when it is swaddled in dust to early adulthood, when it has become a young parent to a family of developing planets. Sprightly "toddler" stars with jets can also be identified in Spitzer's view.

"This is a really busy area to image, with stars everywhere, from the North American complex itself, as well as in front of and behind the region," said Rebull. "We refer to the stars that are not associated with the region as contamination. With Spitzer, we can easily sort this contamination out and clearly distinguish between the young stars in the complex and the older ones that are unrelated."

The North American nebula still has a mystery surrounding it, involving its power source. Nobody has been able to identify the group of massive stars that is thought to be dominating the nebula. The Spitzer image, like images from other telescopes, hints that the missing stars are lurking behind the Gulf of Mexico portion of the nebula. This is evident from the illumination pattern of the nebula, especially when viewed with the detector on Spitzer that picks up 24-micron infrared light. That light appears to be coming from behind the Gulf of Mexico's dark tangle of clouds, in the same way that sunlight creeps out from behind a rain cloud.

The nebula's distance from Earth is also a mystery. Current estimates put it at about 1,800 light-years from Earth. Spitzer will refine this number by finding more stellar members of the North American complex.

The Spitzer observations were made before it ran out of the liquid coolant needed to chill its longer-wavelength instruments. Currently, Spitzer's two shortest-wavelength channels (3.6 and 4.5 microns) are still working. The composite image shows light from both the infrared array camera and multiband imaging processor. Infrared light with a wavelength of 3.6 microns is color-coded blue; 8.0-micron light is green; and 24-micron light is red.

Changing Face of the North American Nebula

Credit NASA/JPL-Caltech/L. Rebull (SSC/Caltech)

This image layout reveals how the appearance of the North American nebula can change dramatically using different combinations of visible and infrared observations from the Digitized Sky Survey and NASA's Spitzer Space Telescope, respectively.

In this progression, the visible-light view (upper left) shows a striking similarity to the North American continent. The image highlights the eastern seaboard and Gulf of Mexico regions. The red region to the right is known as the "Pelican nebula," after its resemblance in visible light to a pelican.

The view at upper right includes both visible and infrared observations. The hot gas comprising the North American continent and the Pelican now takes on a vivid blue hue, while red colors display the infrared light. Inky black dust features start to glow in the infrared view.

In the bottom two images, only infrared light from Spitzer is shown -- data from the infrared array camera is on the left, and data from both the infrared array camera and the multiband imaging photometer, which sees longer wavelengths, is on the right. These pictures look different in part because infrared light can penetrate dust whereas visible light cannot. Dusty, dark clouds in the visible image become transparent in Spitzer's view. In addition, Spitzer's infrared detectors pick up the glow of dusty cocoons enveloping baby stars.

Color is used to display different parts of the spectrum in each of these images. In the visible-light view (upper right) from the Digitized Sky Survey, colors are shown in their natural blue and red hues. The combined visible/infrared image (upper left) shows visible light as blue, and infrared light as green and red. The infrared array camera (lower left) represents light with a wavelength of 3.6 microns as blue, 4.5 microns as green, 5.8 microns as orange, and 8.0 microns as red. In the final image, incorporating the multiband imaging photometer data, light with a wavelength of 3.6 microns has been color coded blue; 4.5-micron light is blue-green; 5.8-micron and 8.0-micron light are green; and 24-micron light is red.

Baby Star and Jets Near the North Americam Nebula
Credit NASA/JPL-Caltech/L. Rebull (SSC/Caltech)

Stars at all stages of development, from dusty little tots to young adults, are on display in a new image from NASA's Spitzer Space Telescope.

The cosmic community is called the North America nebula. In visible light, the region resembles the North American continent, with the most striking resemblance being the Gulf of Mexico. But in Spitzer's infrared view, the continent disappears. Instead, a swirling landscape of dust and young stars comes into view.

This image focuses in on the Gulf of Mexico cluster of young stars. Several hundred young stars, seen here as the red dots, huddle together along their natal dark cloud -- what can be seen as the dark "river." In the main image, data from both the infrared array camera and multiband imaging photometer are included, showing infrared wavelengths of 3.6, 4.5, 5.8, 8, and 24 microns. In the inset, only data from the infrared array camera are shown, including wavelengths of 3.6, 4.5, 5.8, and 8 microns. The inset highlights jets from young stars, seen as green streaks near the stars.

Source: Spizter Space Telescope

NASA's Spitzer Reveals First Carbon-Rich Planet

Hot, Carbon-Rich Planet

Credit: NASA/JPL-Caltech/R. Hurt (SSC)

Exoplanet WASP-12b

Credit: NASA/JPL-Caltech/R. Hurt (SSC)

This plot of data from NASA's Spitzer Space Telescope indicates the presence of molecules in the planet WASP-12b -- a super-hot gas giant that orbits tightly around its star. Spitzer measurements suggest this planet's atmosphere has carbon monoxide, excess methane, and not much water vapor. The results demonstrate that WASP-12b is the first known carbon-rich planet.

Spitzer made these measurements as the planet circled behind the star, in an event called the secondary eclipse. The telescope collected the infrared light from the star and the planet, then just the star as the planet disappeared behind the star. This allowed astronomers to calculate the amount of infrared light coming solely from the planet. The observations were performed at four different wavelengths of infrared light. These data were then combined with previously reported measurements taken by the Canada-France-Hawaii Telescope atop Mauna Kea, Hawaii, at shorter infrared wavelengths to create this plot.

The yellow dots show the data, along with the observational uncertainties. The blue curve is a model of the planet's light, or spectrum, showing the fingerprints of chemicals in the atmosphere. The blue dots represent the blue model curve averaged to cover the same wavelengths as the data, as shown by the gray lines at the bottom of the plot.

PASADENA, Calif. -- Astronomers have discovered that a huge, searing-hot planet orbiting another star is loaded with an unusual amount of carbon. The planet, a gas giant named WASP-12b, is the first carbon-rich world ever observed. The discovery was made using NASA's Spitzer Space Telescope, along with previously published ground-based observations.

"This planet reveals the astounding diversity of worlds out there," said Nikku Madhusudhan of the Massachusetts Institute of Technology, Cambridge, lead author of a report in the Dec. 9 issue of the journal Nature. "Carbon-rich planets would be exotic in every way -- formation, interiors and atmospheres."

It's possible that WASP-12b might harbor graphite, diamond, or even a more exotic form of carbon in its interior, beneath its gaseous layers. Astronomers don't currently have the technology to observe the cores of exoplanets, or planets orbiting stars beyond our sun, but their theories hint at these intriguing possibilities.

The research also supports theories that carbon-rich rocky planets much less massive than WASP-12b could exist around other stars. Our Earth has rocks like quartz and feldspar, which are made of silicon and oxygen plus other elements. A carbon-rich rocky planet could be a very different place.

"A carbon-dominated terrestrial world could have lots of pure carbon rocks, like diamond or graphite, as well as carbon compounds like tar," said Joseph Harrington of the University of Central Florida, in Orlando, who is the principal investigator of the research.

Carbon is a common component of planetary systems and a key ingredient of life on Earth. Astronomers often measure carbon-to-oxygen ratios to get an idea of a star's chemistry. Our sun has a carbon-to-oxygen ratio of about one to two, which means it has about half as much carbon as oxygen. None of the planets in our solar system is known to have more carbon than oxygen, or a ratio of one or greater. However, this ratio is unknown for Jupiter, Saturn, Uranus, and Neptune. Unlike WASP-12b, these planets harbor water -- the main oxygen carrier -- deep inside their atmospheres, making it hard to detect.

WASP-12b is the first planet ever to have its carbon-to-oxygen ratio measured at greater than one (the actual ratio is most likely between one and two). This means the planet has excess carbon, some of which is in the form of atmospheric methane.

"When the relative amount of carbon gets that high, it's as though you flip a switch, and everything changes," said Marc Kuchner, an astronomer at NASA Goddard Space Flight Center, Greenbelt, Md., who helped develop the theory of carbon-rich rocky planets but is not associated with the study. "If something like this had happened on Earth, your expensive engagement ring would be made of glass, which would be rare, and the mountains would all be made of diamonds."

Madhusudhan, Harrington and colleagues used Spitzer to observe WASP-12b as it slipped behind its star, in a technique known as secondary eclipse, which was pioneered for exoplanets by Spitzer. These data were combined with previously published observations taken from the ground with the Canada-France-Hawaii Telescope at Mauna Kea, Hawaii. Madhusudhan used the data to conduct a detailed atmospheric analysis, revealing chemicals such as methane and carbon monoxide in the planet's atmosphere.

WASP-12b derives its name from the consortium that found it, the Wide Angle Search for Planets. It is 1.4 times as massive as Jupiter and located roughly 1,200 light-years away from Earth. This blistering world whips around its star in a little over a day, with one side always facing the star. It is so close to its star that the star's gravity stretches the planet into an egg-like shape. What's more, the star's gravity is siphoning mass off the planet into a thin disk that orbits around with it.

The Spitzer data also reveal more information about WASP-12b's temperature. The world was already known to be one of the hottest exoplanets found so far; the new observations indicate that the side that faces the star is 2,600 Kelvin, or 4,200 degrees Fahrenheit. That's more than hot enough to melt steel.

Other authors of the paper are Kevin Stevenson, Sarah Nymeyer, Christopher Campo, Jasmina Blecic, Ryan Hardy, Nate Lust, Christopher Britt and William Bowman of University of Central Florida, Orlando; Peter Wheatley of the University of Warwick, United Kingdom; Drake Deming of NASA Goddard Space Flight Center, Greenbelt, Md.; David Anderson, Coel Hellier and Pierre Maxted of Keele University, United Kingdom; Andrew Collier-Cameron of the University of St. Andrews, United Kingdom; Leslie Hebb of Vanderbilt University, Nashville, Tenn.; Don Pollacco of Queen's University, United Kingdom; and Richard West of the University of Leicester, United Kingdom.

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov

Spitzer Reveals a Buried Explosion Sparked by a Galactic Train Wreck

Infrared Glow of Stardust Galaxy II ZW 096
Credit:NASA/JPL-Caltech/STScI/H. Inami (SSC/Caltech)

These images show how a brilliant burst of star formation (red glow, right image) is revealed in infrared observations from NASA's Spitzer Space Telescope. The collision of two spiral galaxies, has triggered this luminous starburst, the brightest ever seen taking place far away from the centers, or nuclei, of merging galaxies.

The merging galaxies, known collectively as II Zw 096, can be clearly seen in the image from NASA's Hubble Space Telescope (left). This image combines light spanning the far-ultraviolet through the near-infrared. The real action in this galactic train wreck is barely hinted at in the red speckles near the middle of it all.

The booming blast of star formation only jumps out when Spitzer's mid-infrared view, represented in red, is folded into the mix (right). This tiny region may be as small as 700 light-years across - just a tiny portion of the full 50,000 light-year extent of II Zw 096 - yet it blasts out 80 percent of the infrared light from this galactic tumult. The surrounding shroud of dust renders the stars here nearly invisible in other wavelengths of light.

Researchers were surprised to see such a brilliant infrared glow in an area so far offset from the center of the spiral galaxy. Starbursts are often found crammed into the very centers of merging galaxies, but this is the brightest starburst ever seen outside a galaxy's nucleus. Based on Spitzer data, researchers estimate the starburst is cranking out stars at the breakneck pace of around 100 solar masses, or masses of our Sun, per year.

The Hubble image (left) represents ultraviolet light at a wavelength of 0.15 microns as blue, visible light at 0.44 microns as cyan, and near infrared light at 0.9 microns as red.

In the combined image (right) Hubble's far-ultraviolet and visible light at wavelengths of 0.15 and 0.44 microns is shown as blue, and the near infrared light at 0.9 microns is cyan. Spitzer's infrared light at 4.5 microns is represented by orange, and the mid-infrared light at 8.0 and 24 microns is red.

Astronomers using NASA's Spitzer Space Telescope have found a stunning burst of star formation that beams out as much infrared light as an entire galaxy. The collision of two spiral galaxies has triggered this explosion, which is cloaked by dust that renders its stars nearly invisible in other wavelengths of light.

The starburst newly revealed by Spitzer stands as the most luminous ever seen taking place away from the centers, or nuclei, of merging parent galaxies. It blazes ten times brighter than the nearby Universe's previous most famous "off-nuclear starburst" that gleams in another galactic smashup known as the Antennae Galaxy.

The new findings show that galaxy mergers can pack a real star-making wallop far from the respective galactic centers, where star-forming dust and gases typically pool.

"This discovery proves that merging galaxies can generate powerful starbursts outside of the centers of the parent galaxies," says Hanae Inami, first author of a paper detailing the results in the July issue of The Astronomical Journal. Inami is a graduate student at The Graduate University for Advanced Studies in Japan and the Spitzer Science Center at the California Institute of Technology. She adds: "The infrared light emission of the starburst dominates its host galaxy and rivals that of the most luminous galaxies we see that are relatively close to our home, the Milky Way."

"No matter how you slice it, this starburst is one of the most luminous objects in the local Universe," agrees Lee Armus, second author of the paper and a senior research astronomer also at the Spitzer Science Center.

A dazzling galactic dust-up

Inami, Armus and their colleagues spotted the buried starburst with Spitzer in the interacting galaxies known as II Zw 096. This galactic train wreck - located around 500 million light years away in the constellation Delphinus (the Dolphin) - will continue to unfold for a few hundred million years. Gravitational forces have already dissolved the once-pinwheel shape of one of II Zw 096's pair of merging galaxies.

The ultra-bright starburst region spans 700 light-years or so - just a tiny portion of II Zw 096, which streams across some 50,000 to 60,000 light-years - yet it blasts out 80 percent of the infrared light from this galactic tumult. Based on Spitzer data, researchers estimate the starburst is cranking out stars at the breakneck pace of around 100 solar masses, or masses of our Sun, per year.

The prodigious energy output of this starburst in a decentralized location as revealed in the infrared has surprised the Spitzer researchers. The new observations go to show how the notion of a cosmic object's nature can change tremendously when viewed at different wavelengths of light. In this way, the shapes and dynamics of distant, harder-to-study galactic mergers could turn out to be a good deal more complex than current observations over a narrow range of wavelengths imply.

"Most of the far-infrared emission in II Zw 096, and hence most of the power, is coming from a region that is not associated with the centers of the merging galaxies," Inami explains. "This suggests that the appearances and interactions of distant, early galaxies during epochs when mergers were much more common than today in the Universe might be more complicated than we think."

A fleeting, perhaps prophetic vista?

In galaxy mergers, individual stars rarely slam into one another because of the vast distances separating them; even in the comparatively crowded central hubs of spiral galaxies, trillions of kilometers still often yawn between the stars.

But giant, diffuse clouds of gas and dust in galaxies do crash together - passing through each other somewhat like ocean waves - and in turn spur the gravitational collapse of dense pockets of matter into new stars. These young, hot stars shine intensely in the energetic ultraviolet part of the spectrum. In the case of II Zw 096, however, a thick shroud of gas and dust still surrounds this stellar brood. The blanket of material absorbs the stars' light and re-radiates it in the lower-energy, infrared wavelengths that gleam clear through the dust to Spitzer's camera.

Astronomers were lucky to capture this transient phase in the evolution of the starburst and of the daughter galaxy that will eventually coalesce out of the collision. "Spitzer has allowed us to see the fireworks before all the gas and dust has cleared away, giving us a preview of the exciting new galaxy being built under the blanket," Inami says.

Merging galaxies such as II Zw 096 also offer a sneak peek at the fate of our Milky Way in some 4.5 billion years when it is expected to plow into its nearest large galactic neighbor, the Andromeda Galaxy. Off-nuclear starbursts such as that in II Zw 096 and the Antennae Galaxy could occur in the vicinity of our Solar System, perhaps, which is located about two-thirds of the way out from the Milky Way's glowing, bulging center.

"This kind of dramatic thing happening in II Zw 096 could happen to the Milky Way and Andromeda when they meet in the far future," says Inami.

By Adam Hadhazy

Spitzer Finds a Flavorful Mix of Asteroids

This image, taken by NASA's Near Earth Asteroid Rendezvous mission in 2000, shows a close-up view of Eros, an asteroid with an orbit that takes it somewhat close to Earth. NASA's Spitzer Space Telescope observed Eros and dozens of other near-Earth asteroids as part of an ongoing survey to study their sizes and compositions using infrared light. Image credit: NASA/JHUAPL. Full image and caption

New research from NASA's Spitzer Space Telescope reveals that asteroids somewhat near Earth, termed near-Earth objects, are a mixed bunch, with a surprisingly wide array of compositions. Like a piñata filled with everything from chocolates to fruity candies, these asteroids come in assorted colors and compositions. Some are dark and dull; others are shiny and bright. The Spitzer observations of 100 known near-Earth asteroids demonstrate that the objects’ diversity is greater than previously thought.

The findings are helping astronomers better understand near-Earth objects as a whole -- a population whose physical properties are not well known.

"These rocks are teaching us about the places they come from," said David Trilling of Northern Arizona University, Flagstaff, lead author of a new paper on the research appearing in the September issue of Astronomical Journal. "It's like studying pebbles in a streambed to learn about the mountains they tumbled down."

After nearly six years of operation, in May 2009, Spitzer used up the liquid coolant needed to chill its infrared detectors. It is now operating in a so-called "warm" mode (the actual temperature is still quite cold at 30 Kelvin, or minus 406 degrees Fahrenheit). Two of Spitzer's infrared channels, the shortest-wavelength detectors on the observatory, are working perfectly.

One of the mission's new "warm" programs is to survey about 700 near-Earth objects, cataloguing their individual traits. By observing in infrared, Spitzer is helping to gather more accurate estimates of asteroids' compositions and sizes than what is possible with visible light alone. Visible-light observations of an asteroid won't differentiate between an asteroid that is big and dark, or small and light. Both rocks would reflect the same amount of visible sunlight. Infrared data provide a read on the object's temperature, which then tells an astronomer more about the actual size and composition. A big, dark rock has a higher temperature than a small, light one because it absorbs more sunlight.

Trilling and his team have analyzed preliminary data on 100 near-Earth asteroids so far. They plan to observe 600 more over the next year. There are roughly 7,000 known near-Earth objects out of a population expected to number in the tens to hundreds of thousands.

"Very little is known about the physical characteristics of the near-Earth population," said Trilling. "Our data will tell us more about the population, and how it changes from one object to the next. This information could be used to help plan possible future space missions to study a near-Earth object."

The data show that some of the smaller objects have surprisingly high albedos (an albedo is a measurement of how much sunlight an object reflects). Since asteroid surfaces become darker with time due to exposure to solar radiation, the presence of lighter, brighter surfaces for some asteroids may indicate that they are relatively young. This is evidence for the continuing evolution of the near-Earth object population.

In addition, the fact that the asteroids observed so far have a greater degree of diversity than expected indicates that they might have different origins. Some might come from the main belt between Mars and Jupiter, and others could come from farther out in the solar system. This diversity also suggests that the materials that went into making the asteroids -- the same materials that make up our planets -- were probably mixed together like a big solar-system soup very early in its history.

The research complements that of NASA's Wide-field Infrared Survey Explorer, or WISE, an all-sky infrared survey mission also up in space now. WISE has already observed more than 430 near-Earth objects -- of these, more than 110 are newly discovered.

In the future, both Spitzer and WISE will tell us even more about the "flavors" of near-Earth objects. This could reveal new clues about how the cosmic objects might have dotted our young planet with water and organics -- ingredients needed to kick-start life.

Other authors of the paper include Cristina Thomas, also from Northern Arizona University; Michael Mueller and Marco Delbo of the Observatoire de la Côte d'Azur, Nice, France; Joseph Hora, Giovanni Fazio, Howard Smith and Tim Spahr of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.; Alan Harris of the DLR Institute of Planetary Research, Berlin, Germany (DLR is Germany's space agency and stands for Deutsches Zentrum für Luft- und Raumfahrt); Bidushi Bhattacharya of the NASA Herschel Science Center at the California Institute of Technology, Pasadena; Steve Chesley and Amy Mainzer of NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Bill Bottke of the Southwest Research Institute, Boulder, Colo.; Josh Emery of the University of Tennessee, Knoxville; Bryan Penprase of the Pomona College, Claremont, Calif.; and John Stansberry of the University of Arizona, Tucson.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu .

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.clavin@jpl.nasa.gov