Dark, dusty shells

PGC 10922

Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt

The NASA/ESA Hubble Space Telescope has captured this image of PGC 10922, an example of a lenticular galaxy — a galaxy type that lies on the border between ellipticals and spirals.

Seen face-on, the image shows the disc and tightly-wound spiral structures of dark dust encircling the bright centre of the galaxy. There is also a remarkable outer halo of faint wide arcs or shells extending outwards, covering much of the picture. These are likely to have been formed by a gravitational encounter or even a merger with another galaxy. Some dust also appears to have escaped from the central structure and has spread out across the inner shells.

An extraordinarily rich background of more remote galaxies can also be seen in the image.

A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Judy Schmidt.

Source: ESA/Hubble & NASA - Space Telescope

Hubble Sees a Cosmic Caterpillar

 

 Protostar IRAS 20324+4057

Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and IPHAS

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Compass and Scale Image for Protostar IRAS 20324+4057 
Credit: NASA, ESA, and Z. Levay (STScI/AURA)

This light-year-long knot of interstellar gas and dust resembles a caterpillar on its way to a feast. But the meat of the story is not only what this cosmic caterpillar eats for lunch, but also what's eating it. Harsh winds from extremely bright stars are blasting ultraviolet radiation at this "wanna-be" star and sculpting the gas and dust into its long shape. 

The culprits are 65 of the hottest, brightest known stars, classified as O-type stars, located 15 light-years away from the knot, towards the right edge of the image. These stars, along with 500 less bright, but still highly luminous B-type stars make up what is called the Cygnus OB2 association. Collectively, the association is thought to have a mass more than 30,000 times that of our Sun.

The caterpillar-shaped knot, called IRAS 20324+4057, is a protostar in a very early evolutionary stage. It is still in the process of collecting material from an envelope of gas surrounding it. However, that envelope is being eroded by the radiation from Cygnus OB2. Protostars in this region should eventually become young stars with final masses about one to ten times that of our Sun, but if the eroding radiation from the nearby bright stars destroys the gas envelope before the protostars finish collecting mass, their final masses may be reduced.

Spectroscopic observations of the central star within IRAS 20324+4057 show that it is still collecting material quite heavily from its outer envelope, hoping to bulk up in mass. Only time will tell if the formed star will be a "heavy-weight" or a "light-weight" with respect to its mass.

This image of IRAS 20324+4057 is a composite of Hubble Advanced Camera for Surveys data taken in green and infrared light in 2006, and ground-based hydrogen data from the Isaac Newton Telescope in 2003, as part of the IPHAS H-alpha survey. The object lies 4,500 light-years away in the constellation Cygnus.

For more information, contact:

Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4514

villard@stsci.edu

Zolt Levay
Space Telescope Science Institute, Baltimore, Md.
410-338-4907

levay@stsci.edu

NGC 1232: Dwarf Galaxy Caught Ramming Into a Large Spiral

NGC 1232
Credit: X-ray: NASA/CXC/Huntingdon Inst. for X-ray Astronomy/G.Garmire, 

Optical: ESO/VLT 

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Tour of NGC 1232

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Observations with NASA's Chandra X-ray Observatory have revealed a massive cloud of multimillion-degree gas in a galaxy about 60 million light years from Earth. The hot gas cloud is likely caused by a collision between a dwarf galaxy and a much larger galaxy called NGC 1232. If confirmed, this discovery would mark the first time such a collision has been detected only in X-rays, and could have implications for understanding how galaxies grow through similar collisions.

An image combining X-rays and optical light shows the scene of this collision. The impact between the dwarf galaxy and the spiral galaxy caused a shock wave - akin to a sonic boom on Earth - that generated hot gas with a temperature of about 6 million degrees. Chandra X-ray data, in purple, show the hot gas has a comet-like appearance, caused by the motion of the dwarf galaxy. Optical data from the European Southern Observatory's Very Large Telescope reveal the spiral galaxy in blue and white. X-ray point sources have been removed from this image to emphasize the diffuse emission.

Near the head of the comet-shaped X-ray emission (mouse over the image for the location) is a region containing several very optically bright stars and enhanced X-ray emission. Star formation may have been triggered by the shock wave, producing bright, massive stars. In that case X-ray emission would be generated by massive star winds and by the remains of supernova explosions as massive stars evolve.

The mass of the entire gas cloud is uncertain because it cannot be determined from the two-dimensional image whether the hot gas is concentrated in a thin pancake or distributed over a large, spherical region. If the gas is a pancake, the mass is equivalent to forty thousand Suns. If it is spread out uniformly, the mass could be much larger, about three million times as massive as the Sun. This range agrees with values for dwarf galaxies in the Local Group containing the Milky Way.

The hot gas should continue to glow in X-rays for tens to hundreds of millions of years, depending on the geometry of the collision. The collision itself should last for about 50 million years. Therefore, searching for large regions of hot gas in galaxies might be a way to estimate the frequency of collisions with dwarf galaxies and to understand how important such events are to galaxy growth.

An alternative explanation of the X-ray emission is that the hot gas cloud could have been produced by supernovas and hot winds from large numbers of massive stars, all located on one side of the galaxy. The lack of evidence of expected radio, infrared, or optical features argues against this possibility.

A paper by Gordon Garmire of the Huntingdon Institute for X-ray Astronomy in Huntingdon, PA describing these results is available online and was published in the June 10th, 2013 issue of The Astrophysical Journal.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass. 

Facts for NGC 1232:

Scale: Image is 6.8 arcmin across (About 120,000 light years) 
Category: Normal Galaxies & Starburst Galaxies
Coordinates (J2000): RA 03h 09m 45.51s | Dec -20° 34' 45.48" 
Constellation: Eridanus
Observation Date: 3 pointings between November 2008 & October 2010 
Observation Time: 41 hours 33 (1 day 17 hours) 
Obs. ID: 10720, 10798, 12153 
Instrument: ACIS
References: Garmire, G. 2013, ApJ, 707, 17
Color Code: X-ray (Purple); Optical (Red, Green, Blue)

Oldest Solar Twin Identified

PR Image eso1337a

The life cycle of a Sun-like star (annotated)

PR Image eso1337b

Image of HIP 102152

PR Image eso1337c

Wide-field view of the region around Sun-like star HIP 102152

PR Image eso1337d
The evolution of a solar twin 

Videos

PR Video eso1337a

The life cycle of a Sun-like star

PR Video eso1337b

Zooming in on the oldest solar twin HIP 102152

   

ESO’s VLT provides new clues to help solve lithium mystery

An international team led by astronomers in Brazil has used ESO’s Very Large Telescope to identify and study the oldest solar twin known to date. Located 250 light-years from Earth, the star HIP 102152 is more like the Sun than any other solar twin — except that it is nearly four billion years older. This older, but almost identical, twin gives us an unprecedented chance to see how the Sun will look when it ages. The new observations also provide an important first clear link between a star’s age and its lithium content, and in addition suggest that HIP 102152 may be host to rocky terrestrial planets.

Astronomers have only been observing the Sun with telescopes for 400 years — a tiny fraction of the Sun’s age of 4.6 billion years. It is very hard to study the history and future evolution of our star, but we can do this by hunting for rare stars that are almost exactly like our own, but at different stages of their lives. Now astronomers have identified a star that is essentially an identical twin to our Sun, but 4 billion years older — almost like seeing a real version of the twin paradox in action [1].

Jorge Melendez (Universidade de São Paulo, Brazil), the leader of the team and co-author of the new paper explains: “For decades, astronomers have been searching for solar twins in order to know our own life-giving Sun better. But very few have been found since the first one was discovered in 1997. We have now obtained superb-quality spectra from the VLT and can scrutinise solar twins with extreme precision, to answer the question of whether the Sun is special.”

The team studied two solar twins [2] — one that was thought to be younger than the Sun (18 Scorpii) and one that was expected to be older (HIP 102152). They used the UVES spectrograph on the Very Large Telescope (VLT) at ESO's Paranal Observatory to split up the light into its component colours so that the chemical composition and other properties of these stars could be studied in great detail.

They found that HIP 102152 in the constellation of Capricornus (The Sea Goat) is the oldest solar twin known to date. It is estimated to be 8.2 billion years old, compared to 4.6 billion years for our own Sun. On the other hand 18 Scorpii was confirmed to be younger than the Sun — about 2.9 billion years old.

Studying the ancient solar twin HIP 102152 allows scientists to predict what may happen to our own Sun when it reaches that age, and they have already made one significant discovery. “One issue we wanted to address is whether or not the Sun is typical in composition,” says Melendez. “Most importantly, why does it have such a strangely low lithium content?”

Lithium, the third element in the periodic table, was created in the Big Bang along with hydrogen and helium. Astronomers have pondered for years over why some stars appear to have less lithium than others. With the new observations of HIP 102152, astronomers have taken a big step towards solving this mystery by pinning down a strong correlation between a Sun-like star’s age and its lithium content.

Our own Sun now has just 1% of the lithium content that was present in the material from which it formed. Examinations of younger solar twins have hinted that these younger siblings contain significantly larger amounts of lithium, but up to now scientists could not prove a clear correlation between age and lithium content [3].

TalaWanda Monroe (Universidade de São Paulo), the lead author on the new paper, concludes: “We have found that HIP 102152 has very low levels of lithium. This demonstrates clearly for the first time that older solar twins do indeed have less lithium than our own Sun or younger solar twins. We can now be certain that stars somehow destroy their lithium as they age, and that the Sun's lithium content appears to be normal for its age.” [4]

A final twist in the story is that HIP 102152 has an unusual chemical composition pattern that is subtly different to most other solar twins, but similar to the Sun. They both show a deficiency of the elements that are abundant in meteorites and on Earth. This is a strong hint that HIP 102152 may host terrestrial rocky planets [5].

Notes

[1] Many people have heard of the twin paradox: one identical twin takes a space journey and comes back to Earth younger than their sibling. Although there is no time travelling involved here, we see two distinctly different ages for these two very similar stars — snapshots of the Sun’s life at different stages.

[2] Solar twins, solar analogues and solar-type stars are categories of stars according to their similarity to our own Sun. Solar twins are the most similar to our Sun, as they have very similar masses, temperatures, and chemical abundances. Solar twins are rare but the other classes, where the similarity is less precise, are much more common.

[3] Previous studies have indicated that a star’s lithium content could also be affected if it hosts giant planets (eso0942, eso0118, Nature paper), although these results have been debated (ann1046).

[4] It is still unclear exactly how lithium is destroyed within the stars, although several processes have been proposed to transport lithium from the surface of a star into its deeper layers, where it is then destroyed.

[5] If a star contains less of the elements that we commonly find in rocky bodies, this indicates that it is likely to host rocky terrestrial planets because such planets lock up these elements as they form from a large disc surrounding the star. The suggestion that HIP 102152 may host such planets is further reinforced by the radial velocity monitoring of this star with ESO's HARPS spectrograph, which indicates that inside the star’s habitable zone there are no giant planets. This would allow the existence of potential Earth-like planets around HIP 102152; in systems with giant planets existing close in to their star, the chances of finding terrestrial planets are much less as these small rocky bodies are disturbed and disrupted.

More information

This research was presented in a paper to appear in “High precision abundances of the old solar twin HIP 102152: insights on Li depletion from the oldest Sun”, by TalaWanda Monroe et al. in the Astrophysical Journal Letters.

The team is composed of TalaWanda R. Monroe, Jorge Meléndez (Universidade de São Paulo, Brazil [USP]), Iván Ramírez (The University of Texas at Austin, USA), David Yong (Australian National University, Australia [ANU]), Maria Bergemann (Max Planck Institute for Astrophysics, Germany), Martin Asplund (ANU), Jacob Bean, Megan Bedell (University of Chicago, USA), Marcelo Tucci Maia (USP), Karin Lind (University of Cambridge, UK), Alan Alves-Brito, Luca Casagrande (ANU), Matthieu Castro, José-Dias do Nascimento (Universidade Federal do Rio Grande do Norte, Brazil), Michael Bazot (Centro de Astrofísica da Universidade de Porto, Portugal) and Fabrício C. Freitas (USP).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links

• Research paper
• FAQ about ESO and Brazil
• Photos of the VLT

Contacts

TalaWanda R. Monroe
Universidade de São Paulo
São Paulo, Brazil
Tel: +55 11 3091 2815
Email: tmonroe@usp.br

Jorge Meléndez
Universidade de São Paulo
São Paulo, Brazil
Tel: +55 11 3091 2840
Email: jorge.melendez@iag.usp.br

Richard Hook
ESO, Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org

 

NGC 6357

Credit: ESO

This image, captured by ESO’s Very Large Telescope (VLT) at Paranal, shows a small part of the well-known emission nebula, NGC 6357, located some 8000 light-years away, in the tail of the southern constellation of Scorpius (The Scorpion). The image glows with the characteristic red of an H II region, and contains a large amount of ionised and excited hydrogen gas.

The cloud is bathed in intense ultraviolet radiation — mainly from the open star cluster Pismis 24, home to some massive, young, blue stars — which it re-emits as visible light, in this distinctive red hue.

The cluster itself is out of the field of view of this picture, its diffuse light seen illuminating the cloud on the centre-right of the image. We are looking at a close-up of the surrounding nebula, showing a mesh of gas, dark dust, and newly born and still forming stars.

Source: ESO

Embracing Orion

Herschel’s view of Orion A

The Orion A star-formation cloud seen by ESA’s Herschel space observatory. The Orion Nebula is located within the central bright region of this scene, where massive star formation is most intense. Cooler gas and dust is seen in red and yellow, with point-like sources the seeds of new stars.

The image is a composite of the wavelengths of 70 microns (blue), 160 microns (green) and 250 microns (red) and spans about 1.3 x 2.4 degrees. North is up and east is to the left. 

Copyright: ESA/Herschel/ Ph. André, V. Könyves, N. Schneider (CEA Saclay, France) for the Gould Belt survey Key Programme

This new view of the Orion A star-formation cloud from ESA’s Herschel space observatory shows the turbulent region of space that hugs the famous Orion Nebula. 

The nebula lies about 1500 light years from Earth within the ‘sword of Orion’ – below the three main stars that form the belt of the Orion constellation. 

In this view, the nebula corresponds to the brightest region in the centre of the image, where it is lit up by the Trapezium group of stars at its heart. 

The scene is awash with turbulent star formation, the fierce ultraviolet radiation of massive new born stars blasting away their surrounding cloudy cocoons, carving ethereal shapes into the gas and dust. 

Wispy tendrils rise like flames away from some of the most intense regions of star formation, while pillars of denser material withstand the searing blaze for longer. 

Great arms of gas and dust extend from the Orion Nebula to form a ring, while a spine of cooler material weaves up through the scene to a halo of cloudy star-formation material above.

Embedded within the red and yellow filaments are a handful of point-like sources: these are protostars, the seeds of new stars that will soon ignite and begin to flood their surrounds with intense radiation. 

The black regions to the top of the image and to the bottom right may seem like voids, but actually contain hints of much fainter emission that has not been emphasised in this image. 

The red ‘islands’ of emission in the bottom right are also a subtle trick of image processing for they are connected to the main cloud by much fainter emission. The bright ‘eyes’ in the two most distinct clouds indicates that the tip of each pillar has already collapsed and is forming stars. 

Source: ESA

A Fluffy Disk Around a Baby Star

An international team of astronomers that are members of the Strategic Exploration of Exoplanets and Disks with Subaru Telescope (SEEDS) Project has used Subaru Telescope's High Contrast Instrument for the Subaru Next Generation Adaptive Optics (HiCIAO) to observe a disk around the young star RY Tau (Tauri). The team's analysis of the disk shows that a "fluffy" layer above it is responsible for the scattered light observed in the infrared image. Detailed comparisons with computer simulations of scattered light from the disk reveal that this layer appears to be a remnant of material from an earlier phase of stellar and disk development, when dust and gas were falling onto the disk.

Figure 1: Artist’s rendition of the "fluffy" layer associated with the protoplanetary disk of RY Tau, including jets coming from the star. Although typical young stars like RY Tau are often associated with jets, they are not visible in the HiCIAO observations at this time. (Credit: NAOJ)

Since 2009, the five-year SEEDS Project (Note) has focused on direct imaging of exoplanets, i.e., planets orbiting stars outside of our Solar System, and disks around a targeted total of 500 stars. Planet formation, an exciting and active area for astronomical research, has long fascinated many scientists. Disks of dust and gas that rotate around young stars are of particular interest, because astronomers think that these are the sites where planets form--in these so-called "protoplanetary disks." Since young stars and disks are born in molecular clouds, giant clouds of dust and gas, the role of dust becomes an important feature of understanding planet formation; it relates not only to the formation of rocky, Earth-like planets and the cores of giant Jupiter-like planets but also to that of moons, planetary rings, comets, and asteroids.

As a part of the SEEDS Project, the current team of researchers used HiCIAO mounted on the Subaru Telescope to observe a possible planet-forming disk around the young star RY Tau. This star is about 460 light years away from Earth in the constellation Taurus and is around half a million years old. The disk has a radius of about 70 AU (10 billion kilometers), which is a few times larger than the orbit of Neptune in our own Solar System.

Astronomers have developed powerful instruments to obtain images of protoplanetary disks, and Subaru Telescope's HiCIAO is one of them. HiCIAO uses a mask to block out the light of the central star, which may be a million times brighter than its disk. They can then observe light from the star that has been reflected from the surface of the disk. The scattered light will reveal the structure of the surface of the disk, which is very small in scale and difficult to observe, even with large telescopes. Observers use HiCIAO with a 188 element adaptive optics system to reduce the blurring effects of the Earthʼs atmosphere, making the images significantly sharper. 

This team succeeded in capturing a near-infrared image (1.65 μm) associated with the RY Tau disk. Unlike many other protoplanetary disks, the disk emission is offset from the centre of the star (Figure 2, left). In contrast to longer wavelength observations, which are associated with the midplane of the disk, near-infrared, scattered light coming from the surface of the disk produced this offset (Figure 2, right), which provides information about the vertical structure of the disk.

Figure 2: (left) An image in the near infrared (1.65 μm) around RY Tau, using a special mode of the HiCIAO coronagraph, the polarized intensity image. This type of observation is preferred for faint emissions associated with scattered light around planet-forming disks, as there is less light from the much brighter star. The colors indicate the strength of the emission (blue, yellow and red from faint to bright). A coronagraphic mask in the telescope optics blocks the central star, with its position marked at the center. A white ellipse shows the position of the midplane of the disk, which is observed at millimeter wavelengths. Scattered light observed in the near infrared is offset to the top of the image compared with the denser millimeter disk.
(right) Schematic view of the observed infrared light. The light from the star is scattered in the upper dust layer, and it makes the observed light offset from the midplane. (Credit: NAOJ)

 
Changes in structure perpendicular to the surface of a disk are much harder to investigate because there are few good examples to study. Therefore, the information about vertical structure that this image provides is a contribution to understanding the formation of planets, which depends strongly on the structure of the disk, including structures such as spirals and rings, as well as height.

Figure 3: Computer simulation for dust scattering for RY Tau. The color indicates the strength of the modeled flux (blue, yellow and red for faint to bright). The white contours show the image observed using Subaru Telescope's HiCIAO. This modeled disk has a disk with a fluffy layer and closely matches the image in shape and brightness. (Credit: NAOJ)

The team performed extensive computer simulations of the scattered light, for disks with different masses, shapes, and types of dust (Figure 3). They found that the scattered light is probably not associated with the main surface of the disk, which is the usual explanation for the scattered light image (Figure 4a). Instead, the observed infrared emission can be explained if the emission is associated with a fluffy upper layer, which is almost transparent and not completely transparent (Figure 4b). The team estimated the dust mass in this layer to be about half the mass of Earthʼs Moon.

Figure 4: Schematic views of the structure of the protoplanetary disk. The disk is transparent at millimeter wavelengths, and as a result, the observed millimeter emission is associated with the densest region (the midplane). In contrast, the disk is opaque in the infrared in even at the upper layer. Researchers often assume that the near-infrared emission is due to scattered light from its surface like figure (a). Figure (b) shows the revised schematic view through this study for RY Tau. There is another layer above the two layers in (a). This layer is almost transparent in the near-infrared, but not completely. The team concludes that the scattered emission observed using Subaru Telescope's HiCIAO is mainly due to scattering in this layer. (Credit: NAOJ)

Why is this fluffy layer observed in this disk, but not in many other possible planet-forming disks? The team suspects that this layer is a remnant of the dust that fell onto the star and the disk during earlier stages of formation. In most stars, unlike RY Tau, this layer dissipates by this stage in the formation of the star, but RY Tau may still have it because of its youth. It may act as a special comforter to warm the inside of the disk for baby planets being born there. This may affect the number, size, and composition of the planets being born in this system.

The Atacama Large Millimeter/Submillimeter Array (ALMA), a superb international millimeter/submillimeter telescope, will soon be making extensive observations of protoplanetary disks, which will allow scientists to directly observe ongoing planet formation in the midplane of a disk. By comparing SEEDS and ALMA observations scientists may be able to understand the details of how planets form, something that has raised fascinating questions for centuries.

References:

Takami, M. et al, 2013, Astrophysical Journal, Vol. 772, paper 145, "High-Contrast Near-Infrared Imaging Polarimetry of the Protoplanetary Disk around RY Tau"
Core members of this research team are: M. Takami, J.L. Karr, J. Hashimoto, H. Kim, J. Wisniewski, T. Henning, C. Grady, R. Kandori, K.W. Hodapp, T. Kudo, N. Kusakabe, M.-Y. Chou, Y. Itoh, M. Momose, S. Mayama, and M. Tamura.

Source: Subaru Telescope

Note:

The SEEDS Project began in 2009 for a five-year period, using 120 observing nights at Subaru Telescope, located at the summit of Mauna Kea on the island of Hawaii. The goal of the project is to explore hundreds of nearby stars in an effort to directly image extrasolar planets and protoplanetary/debris disks that surround less massive stars like the Sun. Principal investigator Motohide Tamura (University of Tokyo and NAOJ) leads the project.

Acknowledgements:

This research was supported in part by the following:

• National Science Council grant 100-2112-M-001-007-MY3
• National Science Foundation (U.S.A.) grants 1008440 1009203 and 1009314
• Ministry of Education, Culture, Sports, Science and Technology (MEXT, Japan) Grants-in-Aid for Scientific Research in a Priority Area 2200000, 23103004.
• The Center for the Promotion of Integrated Sciences (CPISS) of The Graduate University for Advanced Studies (SOKENDAI, Japan)

 Source: Subaru Telescope

NASA's Spitzer Telescope Celebrates 10 Years in Space

A montage of images taken by NASA's Spitzer Space Telescope over the years. Image Credit: NASA/JPL-Caltech. See image gallery

Massive stars can wreak havoc on their surroundings, as can be seen in this new view of the Carina nebula from NASA’s Spitzer Space Telescope.Image Credit: NASA/JPL-Caltech. Full image and caption

The spectacular swirling arms and central bar of the Sculptor galaxy are revealed in this new view om NASA’s Spitzer Space Telescope. Image Credit: NASA/JPL-Caltech. Full image and caption

This infrared image from NASA's Spitzer Space Telescope shows the Helix nebula, a cosmic starlet often photographed by amateur astronomers for its vivid colors and eerie resemblance to a giant eye. Image Credit: NASA/JPL-Caltech/Univ.of Ariz. Full image and caption

PASADENA, Calif. -- Ten years after a Delta II rocket launched NASA's Spitzer Space Telescope, lighting up the night sky over Cape Canaveral, Fla., the fourth of the agency's four Great Observatories continues to illuminate the dark side of the cosmos with its infrared eyes.

The telescope studied comets and asteroids, counted stars, scrutinized planets and galaxies, and discovered soccer-ball-shaped carbon spheres in space called buckyballs. Moving into its second decade of scientific scouting from an Earth-trailing orbit, Spitzer continues to explore the cosmos near and far. One additional task is helping NASA observe potential candidates for a developing mission to capture, redirect and explore a near-Earth asteroid.

"President Obama's goal of visiting an asteroid by 2025 combines NASA's diverse talents in a unified endeavor," said John Grunsfeld, NASA's associate administrator for science in Washington. "Using Spitzer to help us characterize asteroids and potential targets for an asteroid mission advances both science and exploration."

Spitzer's infrared vision lets it see the far, cold and dusty side of the universe. Close to home, the telescope has studied the comet dubbed Tempel 1, which was hit by NASA's Deep Impact mission in 2005. Spitzer showed the composition of Tempel 1 resembled that of solar systems beyond our own. Spitzer also surprised the world by discovering the largest of Saturn's many rings. The enormous ring, a wispy band of ice and dust particles, is very faint in visible light, but Spitzer's infrared detectors were able to pick up the glow from its heat.

Perhaps Spitzer's most astonishing finds came from beyond our solar system. The telescope was the first to detect light coming from a planet outside our solar system, a feat not in the mission's original design. With Spitzer's ongoing studies of these exotic worlds, astronomers have been able to probe their composition, dynamics and more, revolutionizing the study of exoplanet atmospheres.

Other discoveries and accomplishments of the mission include getting a complete census of forming stars in nearby clouds; making a  new and improved map of the Milky Way's spiral-arm structure; and, with NASA's Hubble Space Telescope, discovering that the most distant galaxies known are more massive and mature than expected.

"I always knew Spitzer would work, but I had no idea that it would be as productive, exciting and long-lived as it has been," said Spitzer project scientist Michael Werner of NASA's Jet Propulsion Laboratory, Pasadena, Calif., who helped conceive the mission. "The spectacular images that it continues to return, and its cutting-edge science, go far beyond anything we could have imagined when we started on this journey more than 30 years ago."

In October, Spitzer will attempt infrared observations of a small near-Earth asteroid named 2009 DB to better determine its size, a study that will assist NASA in understanding potential candidates for the agency's asteroid capture and redirection mission. This asteroid is one of many candidates the agency is evaluating.

Spitzer, originally called the Space Infrared Telescope Facility, was renamed after its launch in honor of the late astronomer Lyman Spitzer. Considered the father of space telescopes, Lyman Spitzer began campaigning to put telescopes in space, away from the blurring effects of Earth's atmosphere, as early as the 1940s. His efforts also led to the development and deployment of NASA's Hubble Space Telescope, carried to orbit by the space shuttle in 1990.

In anticipation of the Hubble launch, NASA set up the Great Observatories program to fly a total of four space telescopes designed to cover a range of wavelengths: Hubble, Spitzer, the Chandra X-ray Observatory and the now-defunct Compton Gamma Ray Observatory.

"The majority of our Great Observatory fleet is still up in space, each with its unique perspective on the cosmos," said Paul Hertz, Astrophysics Division director at NASA headquarters in Washington. "The wisdom of having space telescopes that cover all wavelengths of light has been borne out by the spectacular discoveries made by astronomers around the world using Spitzer and the other Great Observatories."

Spitzer ran out of the coolant needed to chill its longer-wavelength instruments in 2009, and entered the so-called warm mission phase. Now, after its tenth year of peeling back the hidden layers of the cosmos, its journey continues.

"I get very excited about the serendipitous discoveries in areas we never anticipated," said Dave Gallagher, Spitzer's project manager at JPL from 1999 to 2004, reminding him of a favorite quote from Marcel Proust: "The real voyage of discovery consists not in seeking new landscapes, but in having new eyes."

JPL 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 202-358-5241
Headquarters, Washington                                                   
j.d.harrington@nasa.gov

A cosmic optical illusion

APMBGC 252+125-117, ESO 251-1, PGC 16389

Credit: ESA/Hubble & NASA
Acknowledgement: Luca Limatola

Large JPEG

At first glance, this Hubble picture appears to capture two space colossi entangled in a fierce celestial battle, with two galaxies entwined and merging to form one. But this shows just how easy it is to misinterpret the jumble of sparkling stars and get the wrong impression — as it’s all down to a trick of perspective.

By chance, these galaxies appear to be aligned from our point of view. In the foreground, the irregular dwarf galaxy PGC 16389 — seen here as a cloud of stars — covers its neighbouring galaxy APMBGC 252+125-117, which appears edge-on as a streak. This wide-field image also captures many other more distant galaxies, including a quite prominent face-on spiral towards the right of the picture.

A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by contestant Luca Limatola.

Source: ESA/Hubble - Space Telescope

Hubble Takes Movies of Space Slinky

M87 Jet

Credit: NASA, ESA, E. Meyer, W. Sparks, J. Biretta, J. Anderson, S.T. Sohn, and R. van der Marel (STScI), C. Norman (Johns Hopkins University), and M. Nakamura (Academia Sinica)

Compass and Scale Image for M87 Jet 
Credit: NASA, ESA, and Z. Levay (STScI/AURA)

Magnetic Funnel Around a Supermassive Black Hole  

Credit: NASA, ESA, and A. Feild (STScI)   

More Images

More than thirteen years of observations from NASA's Hubble Space Telescope have allowed astronomers to assemble time-lapse movies of a 5,000-light-year-long jet of superheated gas being ejected from a supermassive black hole in the center of the giant elliptical galaxy M87.

The movies promise to give astronomers a better understanding of how active black holes shape galaxy evolution. While matter drawn completely into a black hole cannot escape its enormous gravitational pull, most infalling material drawn toward it first joins an orbiting region known as an accretion disk encircling the black hole. Magnetic fields surrounding the black hole are thought to entrain some of this ionized gas, ejecting it as very high-velocity jets.

"Central supermassive black holes are a key component in all big galaxies," said Eileen T. Meyer of the Space Telescope Science Institute (STScI) in Baltimore, Md., the Hubble study's lead author. "Most of these black holes are believed to have gone through an active phase, and black-hole-powered jets from this active phase play a key role in the evolution of galaxies. By studying the details of this process in the nearest galaxy with an optical jet, we can hope to learn more about galaxy formation and black hole physics in general."

The Hubble movies reveal for the first time that the jet's river of plasma travels in a spiral motion. This motion is considered strong evidence that the plasma may be traveling along a magnetic field, which the team thinks is coiled like a helix. The magnetic field is believed to arise from a spinning accretion disk of material around a black hole. Although the magnetic field cannot be seen, its presence is inferred by the confinement of the jet along a narrow cone emanating from the black hole.

"We analyzed several years' worth of Hubble data of a relatively nearby jet, which allowed us to see lots of details," Meyer said. "The only reason you see the distant jet in motion at all over just a few years is because it is traveling very fast."

Meyer found evidence for the magnetic field's suspected helical structure in several locations along the jet. In the outer part of the M87 jet, for example, one bright gas clump, called knot B, appears to zigzag, as if it were moving along a spiral path. Several other gas clumps along the jet also appear to loop around an invisible structure. "Past observations of black hole jets couldn't distinguish between radial motion and side-to-side motion, so they didn't provide us with detailed information of the jet's behavior," Meyer explained.

M87 resides at the center of the neighboring Virgo cluster of roughly 2,000 galaxies, located 50 million light-years away. The galaxy's monster black hole is several billion times more massive than our Sun.

In addition, the Hubble data provided information on why the jet is composed of a long string of gas blobs, which appear to brighten and dim over time.

"The jet structure is very clumpy. Is this a ballistic effect, like cannonballs fired sequentially from a cannon?" Meyer asked. "Or, is there some particularly interesting physics going on, such as a shock that is magnetically driven?"

Meyer's team found evidence for both scenarios. "We found things that move quickly," Meyer said. "We found things that move slowly. And, we found things that are stationary. This study shows us that the clumps are very dynamic sources."

The research team spent eight months analyzing 400 observations from Hubble's Wide Field Planetary Camera 2 and Advanced Camera for Surveys. The observations were taken from 1995 to 2008. Several team members, however, have been observing M87 for 20 years. Only Hubble's sharp vision allowed the research team to measure the jet's slight motion in the sky over 13 years. Meyer's team also measured features in the hot plasma as small as 20 light-years wide.

It's too soon to tell whether all black-hole-powered jets behave like the one in M87. That's why Meyer plans to use Hubble to study three more jets. "It's always dangerous to have exactly one example because it could be a strange outlier," Meyer said. "The M87 black hole is justification for looking at more jets."

The team's results will appear Aug. 22 in the online issue of The Astrophysical Journal Letters.

In addition to Eileen Meyer, other members of the science team are William Sparks, John Biretta, Jay Anderson, Sangmo Tony Sohn, and Roeland van der Marel of STScI; Colin Norman of Johns Hopkins University, Baltimore, Md.; and Masanori Nakamura of Academia Sinica, Taipei, Taiwan.

CONTACT

Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4493 / 410-338-4514
dweaver@stsci.edu / villard@stsci.edu

Eileen Meyer
Space Telescope Science Institute, Baltimore, Md.
410-516-5008
meyer@stsci.edu

Free-floating planets may be born free

Tiny, round, cold clouds in space have all the right characteristics to form planets with no parent star. New observations, made with Chalmers University of Technology telescopes, show that not all free-floating planets were thrown out of existing planetary systems. They can also be born free. 

​Previous research has shown that there may be as many as 200 billion free-floating planets in our galaxy, the Milky Way. Until now scientists have believed that such “rogue planets”, which don’t orbit around a star, must have been ejected from existing planetary systems.

New observations of tiny dark clouds in space point out another possibility: that some free-floating planets formed on their own.

A team of astronomers from Sweden and Finland used several telescopes to observe the Rosette Nebula, a huge cloud of gas and dust 4600 light years from Earth in the constellation Monoceros (the Unicorn).

They collected observations in radio waves with the 20-metre telescope at Onsala Space Observatory in Sweden, in submillimetre waves with APEX in Chile, and in infrared light with the New Technology Telescope (NTT) at ESO’s La Silla Observatory in Chile.

”The Rosette Nebula is home to more than a hundred of these tiny clouds – we call them globulettes”, says Gösta Gahm, astronomer at Stockholm University, who led the project.

“They are very small, each with diameter less than 50 times the distance between the Sun and Neptune. Previously we were able to estimate that most of them are of planetary mass, less than 13 times Jupiter’s mass. Now we have much more reliable measures of mass and density for a large number of these objects, and we have also precisely measured how fast they are moving relative to their environment”, he says.

 “We found that the globulettes are very dense and compact, and many of them have very dense cores. That tells us that many of them will collapse under their own weight and form free-floating planets. The most massive of them can form so-called brown dwarfs”, says team member Carina Persson, astronomer at Chalmers University of Technology.

Brown dwarfs, sometimes called failed stars, are bodies whose mass lies between that of planets and stars.

The study shows that the tiny clouds are moving outwards through the Rosette Nebula at high speed, about 80 000 kilometres per hour.

”We think that these small, round clouds have broken off from tall, dusty pillars of gas which were sculpted by the intense radiation from young stars. They have been accelerated out from the centre of the nebula thanks to pressure from radiation from the hot stars in its centre”, explains Minja Mäkelä, astronomer at the University of Helsinki.

According to Gösta Gahm and his team, the tiny dark clouds are being thrown out of the Rosette Nebula. During the history of the Milky Way, countless millions of nebulae like the Rosette have bloomed and faded away. In all of these, many globulettes would have formed.

Astronomers have found that tiny, round, dark clouds called globulettes have the right characteristics to form free-floating planets. The graph shows the spectrum of one of the globulettes taken at the 20-metre telescope at Onsala Space Observatory. Radio waves from molecules of carbon monoxide (13CO) give information on the mass and structure of these clouds. ESO/M. Mäkelä

More about exoplanets and free-floating planets

Astronomers know of almost 900 planets which orbit around other stars than the Sun, but free-floating planets have also been found. Some have been discovered using a technique called microlensing, in which the planet is found when it passes in front of a background star, temporarily making it look brighter. This is an effect predicted by Einstein’s theory of general relativity, in which the light from the star is bent when the planet passes in front of it, a so-called gravitational lens. Scientists have estimated that the number of free-floating planets in our galaxy may exceed 200 billion.

More about the research

The study has been published in the article Mass and motion of globulettes in the Rosette Nebula​ in the July issue of the journal Astronomy & Astrophysics. The team consists of Gösta Gahm (Stockholm University, Sweden), Carina M. Persson (Onsala Space Observatory at Chalmers University of Technology, Sweden), Minja M. Mäkelä (Department of Physics, University of Helsinki, Finland) and Lauri K. Haikala (Finnish Centre for Astronomy with ESO [FINCA], University of Turku, Finland).

More about the telescopes

The team observed radio waves from molecules of carbon monoxide using the 20-metre radio telescope at Onsala Space Observatory, Sweden, and submillimetre light with the telescope APEX at 5100 metres altitude in the Atacama desert in northern Chile. APEX is a collaboration between the Max Planck Institute for Radio Astronomy in Bonn, Germany, Onsala Space Observatory and ESO, with operations of the telescope entrusted to ESO. Observations in infrared light were made using the 3.58 metre New Technology Telescope (NTT) at ESO’s La Silla Observatory.

More about Onsala Space Observatory

Onsala Space Observatory is Sweden's national facility for radio astronomy. The observatory provides researchers with equipment for the study of the earth and the rest of the universe. In Onsala, 45 km south of Gothenburg, it operates two radio telescopes and a station in the international telescope Lofar. It also participates in several international projects. The observatory is hosted by Department of Earth and Space Sciences at Chalmers University of Technology, and is operated on behalf of the Swedish Research Council.

For more information, please contact:

Robert Cumming, 

astronomer and communications officer, 

Onsala Space Observatory at Chalmers University of Technology, 

+46 31-772 55 00 or +46-70-493 31 14, 

email:   robert.cumming@chalmers.se

Gösta Gahm, astronomer, 

Stockholm University, 

+46-73-785 70 71,

email: gahm@astro.su.se

Carina Persson, 

astronomer, 

Onsala Space Observatory at Chalmers University of Technology, 

+46 31-772 55 37, 

email: carina.persson@chalmers.se

Minja Mäkelä, 

Department of Physics, 

University of Helsinki, 

+358-9-191 50811,

email:  minja.makela@helsinki.fi​

 

NASA Spacecraft Capture an Earth Directed Coronal Mass Ejection

The SOHO LASCO C2 instrument captured this image of the Earth-directed CME. SOHO's coronographs are able to take images of the solar corona by blocking the light coming directly from the Sun with an occulter disk. The location of the actual sun is shown with an image taken by SDO. Image Credit: ESA & NASA/SOHO, SDO

The SOHO LASCO C3 instrument captured this coronographic image of the Earth-directed CME. The bright white object to the right is the planet Mercury. Image Credit: ESA & NASA/SOHO

On August 20, 2013 at 4:24 am EDT, the sun erupted with an Earth-directed coronal mass ejection or CME, a solar phenomenon which can send billions of tons of particles into space that can reach Earth one to three days later. These particles cannot travel through the atmosphere to harm humans on Earth, but they can affect electronic systems in satellites and on the ground.

Experimental NASA research models, based on observations from NASA’s Solar Terrestrial Relations Observatory show that the CME left the sun at speeds of around 570 miles per second, which is a fairly typical speed for CMEs.

Earth-directed CMEs can cause a space weather phenomenon called a geomagnetic storm, which occurs when they funnel energy into Earth's magnetic envelope, the magnetosphere, for an extended period of time. The CME’s magnetic fields peel back the outermost layers of Earth's fields changing their very shape. In the past, geomagnetic storms caused by CMEs of this strength have usually been mild.

Magnetic storms can degrade communication signals and cause unexpected electrical surges in power grids. They also can cause aurora.

NOAA's Space Weather Prediction Center (http://swpc.noaa.gov) is the U.S. government's official source for space weather forecasts, alerts, watches and warnings.

Updates will be provided if needed.

Susan Hendrix
NASA's Goddard Space Flight Center, Greenbelt, Md. 

ALMA Takes Close Look at Drama of Starbirth

PR Image eso1336a

Stunning ALMA and NTT image of Newborn Star

PR Image eso1336b

ALMA’s view of the outflow associated with the Herbig-Haro object HH 46/47

PR Image eso1336c

The Herbig-Haro object HH 46/47 seen with ESO’s New Technology Telescope

PR Image eso1336d

Wide-field view of the star-forming region around the Herbig-Haro object HH 46/47 

PR Image eso1336e

The Herbig-Haro object HH 46/47 in the constellation of Vela

  Videos

PR Video eso1336a

Zooming in on the Herbig-Haro object HH 46/47

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have obtained a vivid close-up view of material streaming away from a newborn star. By looking at the glow coming from carbon monoxide molecules in an object called Herbig-Haro 46/47 they have discovered that its jets are even more energetic than previously thought. The very detailed new images have also revealed a previously unknown jet pointing in a totally different direction.

Young stars are violent objects that eject material at speeds as high as one million kilometres per hour. When this material crashes into the surrounding gas it glows, creating a Herbig-Haro object [1]. A spectacular example is named Herbig-Haro 46/47 and is situated about 1400 light-years from Earth in the southern constellation of Vela (The Sails). This object was the target of a study using ALMA during the Early Science phase, whilst the telescope was still under construction and well before the array was completed.

The new images reveal fine detail in two jets, one coming towards Earth and one moving away. The receding jet was almost invisible in earlier pictures made in visible light, due to obscuration by the dust clouds surrounding the new-born star. ALMA has not only provided much sharper images than earlier facilities but also allowed astronomers to measure how fast the glowing material is moving through space.

These new observations of Herbig-Haro 46/47 revealed that some of the ejected material had velocities much higher than had been measured before. This means the outflowing gas carries much more energy and momentum than previously thought.

The team leader and first author of the new study, Héctor Arce (Yale University, USA) explains that "ALMA's exquisite sensitivity allows the detection of previously unseen features in this source, like this very fast outflow. It also seems to be a textbook example of a simple model where the molecular outflow is generated by a wide-angle wind from the young star."

The observations were obtained in just five hours of ALMA observation time – even though ALMA was still under construction at the time – similar quality observations with other telescopes would have taken ten times longer.

"The detail in the Herbig-Haro 46/47 images is stunning. Perhaps more stunning is the fact that, for these types of observations, we really are still in the early days. In the future ALMA will provide even better images than this in a fraction of the time," adds Stuartt Corder (Joint ALMA Observatory, Chile), a co-author on the new paper.

Diego Mardones (Universidad de Chile), another co-author, emphasises that "this system is similar to most isolated low mass stars during their formation and birth. But it is also unusual because the outflow impacts the cloud directly on one side of the young star and escapes out of the cloud on the other. This makes it an excellent system for studying the impact of the stellar winds on the parent cloud from which the young star is formed."

The sharpness and sensitivity achieved by these ALMA observations also allowed the team to discover an unsuspected outflow component that seems to be coming from a lower mass companion to the young star. This secondary outflow is seen almost at right angles to the principal object and is apparently carving its own hole out of the surrounding cloud.

Arce concludes that "ALMA has made it possible to detect features in the observed outflow much more clearly than previous studies. This shows that there will certainly be many surprises and fascinating discoveries to be made with the full array. ALMA will certainly revolutionise the field of star formation!"

Notes

[1] The astronomers George Herbig and Guillermo Haro were not the first to see one of the objects that now bear their names, but they were the first to study the spectra of these strange objects in detail. They realised that they were not just clumps of gas and dust that reflected light, or glowed under the influence of the ultraviolet light from young stars, but were a new class of objects associated with shocks created by material ejected at high speeds in star formation regions.

More information

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern Observatory (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

This research was presented in a paper entitled "ALMA Observations of the HH 46/47 Molecular Outflow" by Héctor Arce et al, to appear in the Astrophysical Journal.

The team is composed of Héctor G. Arce (Yale University, New Haven, USA), Diego Mardones (Universidad de Chile, Santiago, Chile), Stuartt A. Corder (Joint ALMA Observatory, Santiago, Chile), Guido Garay (Universidad de Chile), Alberto Noriega-Crespo (Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, USA) and Alejandro C. Raga (Instituto de Ciencias Nucleares, Mexico).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world's largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

Links

• Research paper
• More about ALMA
• Photos of ALMA

Contacts

Héctor Arce
Yale University
New Haven, USA
Tel: +1 203 432 3018
Email: hector.arce@yale.edu

Diego Mardones
Universidad de Chile
Santiago, Chile
Tel: + 56 2 977 1143
Email: dmardone@das.uchile.cl

Stuartt Corder
Joint ALMA Observatory
Santiago, Chile
Email: scorder@alma.cl

Lars Lindberg Christensen
Head, ESO education and Public Outreach Department
Garching bei München, Germany
Cell: +49 173 38 72 621
Email: lars@eso.org