Astronomers may have discovered the answer to a mysterious stellar event

By using multiple radio telescopes together, the team were able to trace the radio source to a specific object in the sky.
Credit: Hurley-Walker et al.

Researchers from the Curtin node of the International Centre for Radio Astronomy Research (ICRAR) have made a record-breaking astrophysical discovery while simultaneously uncovering a possible explanation for the rare and extreme astrophysical event known as long-period radio transients.

Associate Professor Natasha Hurley-Walker, along with Csanád Horváth, a Curtin undergraduate student at the time, discovered a pulse of bright energy coming from deep space among archival low-frequency data from the MWA (Murchison Widefield Array), a precursor radio telescope to the SKAO (Square Kilometre Array Observatory). The energy pulse occurs every three hours and lasts 30-60 seconds, making this the longest-period radio transient ever detected.

Long-period radio transients are relatively new to science, and it has been an ongoing mystery how they generate radio waves. With this discovery, researchers believe they have also identified the probable source of the energy burst, potentially shedding light on the long radio transients.

All other previously discovered transients have been deep within our busy galaxy, surrounded by stars, making it challenging to determine precisely what is generating the radio waves. Associate Professor Hurley-Walker explains, “The long-period transients are very exciting, and for astronomers to understand what they are, we need an optical image. However, when you look toward them, there are so many stars lying in the way that it’s like 2001: A Space Odyssey. ‘My god, it’s full of stars!’.”

In a stroke of good fortune, the newly discovered transient, named GLEAM-X J0704-37, was found on the outskirts of our galaxy, in a much emptier region of space in the Puppis constellation, around 5000 light years away.

“Our new discovery lies far off the Galactic Plane, so there are only a handful of stars nearby, and we’re now certain one star system, in particular, is generating the radio waves.”

The signal was detected in a less crowded part of the sky, within the constellation Puppis, which allowed the team to pinpoint its source in the sky.

The team was able to pinpoint the location of the radio waves to one specific star using another SKA precursor, the MeerKAT telescope in South Africa. Following up with the SOAR observatory in Chile, they determined the star’s spectrum, finding it was a low-mass star, an ‘M dwarf’.

This finding both created and answered some pressing questions. Associate Professor Hurley-Walker explains, “An M dwarf alone couldn’t generate the amount of energy we’re seeing.

“The M dwarfs are low-mass stars that have a mere fraction of the Sun’s mass and luminosity. They constitute 70 per cent of the stars in the Milky Way, but not one of them is visible to the naked eye.”

“Our data suggests that it is in a binary with another object, which is likely to be a white dwarf, the stellar core of a dying star. Together, they power radio emission.”

Artist’s impression video of the exotic binary star system AR Scorpii

Astronomers have detected similar pairs of objects, like this one discovered in 2016, but had not previously linked them to long period radio transients. Credit: ESO/L. Calçada/University of Warwick

The team is working on follow-up observations that will conclusively determine the nature of the system, and the explanation of this extreme astrophysical event.

Upon digging through the MWA archives, the astronomers found that GLEAM-X J0704-37 has been active for at least ten years since the MWA started observing; however, it could have been active and undiscovered for even longer, implying there are still many more to be found in archives around the world.

MWA Director, Professor Steven Tingay, said, “These long-period radio transients are new scientific discoveries and the MWA has fundamentally enabled the discoveries.” “The MWA has a 55-petabyte archive of observations that provide a decade-long record of our Universe. It is like having the data storage equivalent of 55,000 high-end home computers – one of the biggest single collections of science data in the world. It is an absolute gold mine for discovering more phenomena in our Universe, and the data are a playground for astronomers,” Professor Tingay said.

The research was published overnight in The Astrophysical Journal Letters.

The radio signal was detected in data from the Murchison Widefield Array radio telescope, located at Inyarrimanha Ilgari Bundara, CSIRO’s Murchison Radio-astronomy Observatory. Credit: ICRAR/Curtin

Astronomers find possible cause for mystery signals (vimeo)

Source: International Center for Radio Astronomy Research (ICRAR)/News

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Publication

‘A 2.9-hour periodic radio transient with an optical counterpart’, published in The Astrophysical Journal Letters – November 2024

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A Rare Look at the Surface of a Rocky Exoplanet

An artist's conception of The Earth-sized exoplanet LHS 3844b which orbits a small star 49 light-years from Earth. It may be covered in dark volcanic rock, according to observations by NASA’s Spitzer Space Telescope. The Spitzer data also suggest the planet has little to no atmosphere. Credit: NASA/JPL-Caltech/R. Hurt (IPAC). High Resolution (jpg) - Low Resolution (jpg)

Detecting Light from Exoplanet LHS 3844b 
Credit: NASA/JPL-Caltech/L. Kreidberg (CfA | Harvard & Smithsonian)

Low Resolution (jpg)

An artist's conception of The Earth-sized exoplanet LHS 3844b which orbits a small star 49 light-years from Earth. It may be covered in dark volcanic rock, according to observations by NASA’s Spitzer Space Telescope. The Spitzer data also suggest the planet has little to no atmosphere. Credit: NASA/JPL-Caltech/R. Hurt (IPAC). Animation (mov)

Cambridge, MA - With an 11-hour orbit around its parent star, the hot planet most likely has no atmosphere, and may be covered in dark lava rock, according to data from the IRAC camera on NASA's Spitzer telescope.

A new study using data from the IRAC camera on NASA's Spitzer Space Telescope provides a rare glimpse at the conditions on the surface of a rocky planet around anther star. The exoplanet very likely has little to no atmosphere, according to the data, and could be covered in the same cooled volcanic material that comprises the dark lunar regions known as mare. The exoplanet therefore might be similar to Mercury, or to Earth's Moon.

This exoplanet discovery, published today (August 19, 2019) in the journal Nature, is just the latest in a series of nearly 700 refereed exoplanet publications relying on IRAC since 2009 when Spitzer’s Warm Mission began and IRAC became its only operating instrument. The IRAC camera’s PI-team is based at the CfA and is led by Giovanni Fazio.

The planet, LHS 3844b, was discovered in 2018 by NASA's Transiting Exoplanet Satellite Survey (TESS) mission, is located 48.6 light-years from Earth, and has a radius 1.3 times that of Earth. It orbits a small, cool type of star called an M dwarf — especially noteworthy because, as one of the most common and long-lived types of stars in the Milky Way galaxy, M dwarfs may host a high percentage of the total number of planets in the galaxy. TESS found the planet via the transit method which detects when the observed light from a parent star dims as its orbiting exoplanet crosses the line-of-sight between the star and Earth. TESS’s Director of Science is CfA astronomer Dave Latham, and CfA astronomers are key members of the TESS Science Office Core and other TESS teams.

During follow-up observations, IRAC was able to detect light from the surface of LHS 3844b. The planet makes one full revolution around its parent star in just 11 hours. With such a tight orbit, LHS 3844b is most likely "tidally locked" with one side of the planet permanently facing the star. The star-facing side, or dayside, is about 1,410 degrees Fahrenheit (770 degrees Celsius). Being relatively hot, the planet radiates copious amounts of infrared light which IRAC, an infrared camera, is able to measure. This observation marks the first time IRAC data have been able to provide information about the atmosphere of a terrestrial-sized world around an M dwarf.

The Search for Life

By measuring the temperature difference between the planet's hot and cold sides, the team concluded that there is a negligible amount of heat being transferred between the two. If an atmosphere were present, hot air on the dayside would naturally expand, generating winds that would transfer heat around the planet. On a rocky world with little to no atmosphere, like the Moon, there is no air present to transfer heat. "The temperature contrast on this planet is about as big as it can possibly be," said CfA researcher Laura Kreidberg, lead author of the new study. "That matches beautifully with our model of a bare rock with no atmosphere."

Understanding the factors that could preserve or destroy planetary atmospheres is part of how scientists plan to search for habitable environments beyond our solar system. Earth's atmosphere is the reason liquid water can exist on the surface, enabling life to thrive. On the other hand, the atmospheric pressure of Mars is now less than 1% of Earth's, and the oceans and rivers that once dotted the Red Planet's surface have disappeared.

"We've got lots of theories about how planetary atmospheres fare around M dwarfs, but we haven't been able to study them empirically," Kreidberg said. "Now, with LHS 3844b, we have a terrestrial planet outside our solar system where for the first time we can determine observationally that an atmosphere is not present."

Compared to Sun-like stars, M dwarfs emit relatively high levels of ultraviolet light, which is harmful to life and can erode a planet's atmosphere. They're particularly violent in their youth, belching up a large number of flares -- bursts of radiation and particles that can strip away budding planetary atmospheres.

The IRAC observations rule out an atmosphere with more than 10 times the pressure of Earth's. An atmosphere between 1 and 10 bars on LHS 3844b has been almost entirely ruled out, although the authors note a slim chance it could exist if the stellar and planetary properties were to meet some very specific and unlikely criteria. (Measured in units called bars, Earth's atmospheric pressure at sea level is about 1 bar.) They also argue that with the planet so close to a star, a thin atmosphere would be stripped away by the star's intense radiation and winds. "I'm still hopeful that other planets around M dwarfs could keep their atmospheres," Kreidberg said. "The terrestrial planets in our solar system are enormously diverse, and I expect the same will be true for exoplanet systems."

A Bare Rock

The authors of the new study went one step further, using LHS 3844b's surface albedo (or its reflectiveness) to try to infer its composition. The Nature study shows that LHS 3844b is "quite dark," according to co-author Renyu Hu, an exoplanet scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, which manages Spitzer. He and his co-authors believe the planet is covered with basalt, a kind of volcanic rock. "We know that the mare of the Moon are formed by ancient volcanism," Hu said, "and we postulate that this might be what has happened on this planet."

IRAC/Spitzer and NASA's Hubble Space Telescope have previously gathered information about the atmospheres of multiple gas planets, but LHS 3844b appears to be the smallest planet for which scientists have used the light coming from its surface to learn about its atmosphere (or lack thereof). IRAC previously used the transit method to study the seven rocky worlds around the TRAPPIST-1 star (also an M dwarf) and learn about their possible overall composition; for instance, some of them likely contain water ice. NASA plans to terminate the Spitzer/IRAC operations in February, 2020, as a cost-savings measure.

Headquartered in Cambridge, Mass., the Center for Astrophysics | Harvard & Smithsonian (CfA) is a collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe. This release is based on Spitzer-JPL release 2019-113.

For more information, contact:

Tyler Jump
Public Affairs
Center for Astrophysics | Harvard & Smithsonian
+1 617-495-7462
tyler.jump@cfa.harvard.edu

Source: Harvard-Smithsonian Center for Astrophysics (CfA)

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Superflares From Young Red Dwarf Stars Imperil Planets

Violent outbursts of seething gas from young red dwarf stars may make conditions uninhabitable on fledgling planets. In this artist's rendering, an active, young red dwarf (right) is stripping the atmosphere from an orbiting planet (left). Scientists found that flares from the youngest red dwarfs they surveyed — approximately 40 million years old — are 100 to 1,000 times more energetic than when the stars are older. They also detected one of the most intense stellar flares ever observed in ultraviolet light — more energetic than the most powerful flare ever recorded from our Sun. Credits: NASA, ESA and D. Player (STScI)

The word "HAZMAT" describes substances that pose a risk to the environment, or even to life itself. Imagine the term being applied to entire planets, where violent flares from the host star may make worlds uninhabitable by affecting their atmospheres.

NASA's Hubble Space Telescope is observing such stars through a large program called HAZMAT — Habitable Zones and M dwarf Activity across Time.

"M dwarf" is the astronomical term for a red dwarf star — the smallest, most abundant and longest-lived type of star in our galaxy. The HAZMAT program is an ultraviolet survey of red dwarfs at three different ages: young, intermediate, and old.

Stellar flares from red dwarfs are particularly bright in ultraviolet wavelengths, compared with Sun-like stars. Hubble's ultraviolet sensitivity makes the telescope very valuable for observing these flares. The flares are believed to be powered by intense magnetic fields that get tangled by the roiling motions of the stellar atmosphere. When the tangling gets too intense, the fields break and reconnect, unleashing tremendous amounts of energy.

The team has found that the flares from the youngest red dwarfs they surveyed — just about 40 million years old — are 100 to 1,000 times more energetic than when the stars are older. This younger age is when terrestrial planets are forming around their stars.

Approximately three-quarters of the stars in our galaxy are red dwarfs. Most of the galaxy's "habitable-zone" planets — planets orbiting their stars at a distance where temperatures are moderate enough for liquid water to exist on their surface — likely orbit red dwarfs. In fact, the nearest star to our Sun, a red dwarf named Proxima Centauri, has an Earth-size planet in its habitable zone.

However, young red dwarfs are active stars, producing ultraviolet flares that blast out so much energy that they could influence atmospheric chemistry and possibly strip off the atmospheres of these fledgling planets.

"The goal of the HAZMAT program is to help understand the habitability of planets around low-mass stars," explained Arizona State University's Evgenya Shkolnik, the program's principal investigator. "These low-mass stars are critically important in understanding planetary atmospheres."

The results of the first part of this Hubble program are being published in The Astrophysical Journal. This study examines the flare frequency of 12 young red dwarfs. "Getting these data on the young stars has been especially important, because the difference in their flare activity is quite large as compared to older stars," said Arizona State University's Parke Loyd, the first author on this paper.

The observing program detected one of the most intense stellar flares ever observed in ultraviolet light. Dubbed the "Hazflare," this event was more energetic than the most powerful flare from our Sun ever recorded.

"With the Sun, we have a hundred years of good observations," Loyd said. "And in that time, we've seen one, maybe two, flares that have an energy approaching that of the Hazflare. In a little less than a day's worth of Hubble observations of these young stars, we caught the Hazflare, which means that we're looking at superflares happening every day or even a few times a day."

Could super-flares of such frequency and intensity bathe young planets in so much ultraviolet radiation that they forever doom chances of habitability? According to Loyd, "Flares like we observed have the capacity to strip away the atmosphere from a planet. But that doesn't necessarily mean doom and gloom for life on the planet. It just might be different life than we imagine. Or there might be other processes that could replenish the atmosphere of the planet. It's certainly a harsh environment, but I would hesitate to say that it is a sterile environment."

The next part of the HAZMAT study will be to study intermediate-aged red dwarfs that are 650 million years old. Then the oldest red dwarfs will be analyzed and compared with the young and intermediate stars to understand the evolution of the ultraviolet radiation environment of low-mass planets around these low-mass stars. The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.

Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4488 / 410-338-4514
jenkins@stsci.edu / villard@stsci.edu

Evgenya Shkolnik
Arizona State University, Tempe, Arizona 808-292-9088
shkolnik@asu.edu

Parke Loyd
Arizona State University, Tempe, Arizona
parke@asu.edu

Editor: Karl Hille

Source: NASA/Hubble

NASA's Kepler Discovers First Earth-Size Planet In The 'Habitable Zone' of Another Star

The artist's concept depicts Kepler-186f , the first validated Earth-size planet to orbit a distant star in the habitable zone. Image Credit: NASA Ames/SETI Institute/JPL-Caltech. Kepler-186f, the first Earth-size Planet in the Habitable Zone

 

The diagram compares the planets of our inner solar system to Kepler-186, a five-planet star system about 500 light-years from Earth in the constellation Cygnus. The five planets of Kepler-186 orbit an M dwarf, a star that is is half the size and mass of the sun. Image Credit: NASA Ames/SETI Institute/JPL-Caltech. Kepler-186 and the Solar System

 

Using NASA's Kepler Space Telescope, astronomers have discovered the first Earth-size planet orbiting a star in the "habitable zone" -- the range of distance from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that planets the size of Earth exist in the habitable zone of stars other than our sun.

While planets have previously been found in the habitable zone, they are all at least 40 percent larger in size than Earth and understanding their makeup is challenging. Kepler-186f is more reminiscent of Earth.

"The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth," said Paul Hertz, NASA's Astrophysics Division director at the agency's headquarters in Washington. "Future NASA missions, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will discover the nearest rocky exoplanets and determine their composition and atmospheric conditions, continuing humankind's quest to find truly Earth-like worlds."

Although the size of Kepler-186f is known, its mass and composition are not. Previous research, however, suggests that a planet the size of Kepler-186f is likely to be rocky.

"We know of just one planet where life exists -- Earth. When we search for life outside our solar system we focus on finding planets with characteristics that mimic that of Earth," said Elisa Quintana, research scientist at the SETI Institute at NASA's Ames Research Center in Moffett Field, Calif., and lead author of the paper published today in the journal Science. "Finding a habitable zone planet comparable to Earth in size is a major step forward."

Kepler-186f resides in the Kepler-186 system, about 500 light-years from Earth in the constellation Cygnus. The system is also home to four companion planets, which orbit a star half the size and mass of our sun. The star is classified as an M dwarf, or red dwarf, a class of stars that makes up 70 percent of the stars in the Milky Way galaxy.

"M dwarfs are the most numerous stars," said Quintana. "The first signs of other life in the galaxy may well come from planets orbiting an M dwarf."

Kepler-186f orbits its star once every 130-days and receives one-third the energy from its star that Earth gets from the sun, placing it nearer the outer edge of the habitable zone. On the surface of Kepler-186f, the brightness of its star at high noon is only as bright as our sun appears to us about an hour before sunset.

"Being in the habitable zone does not mean we know this planet is habitable. The temperature on the planet is strongly dependent on what kind of atmosphere the planet has," said Thomas Barclay, research scientist at the Bay Area Environmental Research Institute at Ames, and co-author of the paper. "Kepler-186f can be thought of as an Earth-cousin rather than an Earth-twin. It has many properties that resemble Earth."

The four companion planets, Kepler-186b, Kepler-186c, Kepler-186d, and Kepler-186e, whiz around their sun every four, seven, 13, and 22 days, respectively, making them too hot for life as we know it. These four inner planets all measure less than 1.5 times the size of Earth.

The next steps in the search for distant life include looking for true Earth-twins -- Earth-size planets orbiting within the habitable zone of a sun-like star -- and measuring the their chemical compositions. The Kepler Space Telescope, which simultaneously and continuously measured the brightness of more than 150,000 stars, is NASA's first mission capable of detecting Earth-size planets around stars like our sun.

Ames is responsible for Kepler's ground system development, mission operations, and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science Mission Directorate.

The SETI Institute is a private, nonprofit organization dedicated to scientific research, education and public outreach.  The mission of the SETI Institute is to explore, understand and explain the origin, nature and prevalence of life in the universe.

For more information about the Kepler mission, visit: http://www.nasa.gov/kepler

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Media contacts:

Michele Johnson
Ames Research Center, Moffett Field, Calif.
650-604-6982
michele.johnson@nasa.gov

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

Gravity-Bending Find Leads to Kepler Meeting Einstein

 

This artist's concept depicts a dense, dead star called a white dwarf crossing in front of a small, red star. The white dwarf's gravity is so great it bends and magnifies light from the red star. Image credit: NASA/JPL-Caltech.  › Full image and caption

This chart shows data from NASA's Kepler space telescope, which looks for planets by monitoring changes in the brightness of stars. As planets orbit in front of a star, they block the starlight, causing periodic dips. The plot on the left shows data collected by Kepler for a star called KOI-256, which is a small red dwarf. At first, astronomers thought the dip in starlight was due to a large planet passing in front of the star. But certain clues, such as the sharpness of the dip, indicated it was actually a white dwarf -- the dense, heavy remains of a star that was once like our sun. In fact, in the data shown at left, the white dwarf is passing behind the red dwarf, an event referred to as a secondary eclipse. The change in brightness is a result of the total light of the system dropping. Image credit: NASA/Ames/JPL-Caltech.  › Full image and caption  - enlarge image

 

 Dead Star Warps Light of Red Star

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NASA's Kepler space telescope has witnessed the effects of a dead star bending the light of its companion star. The findings are among the first detections of this phenomenon -- a result of Einstein's theory of general relativity -- in binary, or double, star systems.

The dead star, called a white dwarf, is the burnt-out core of what used to be a star like our sun. It is locked in an orbiting dance with its partner, a small "red dwarf" star. While the tiny white dwarf is physically smaller than the red dwarf, it is more massive.

"This white dwarf is about the size of Earth but has the mass of the sun," said Phil Muirhead of the California Institute of Technology, Pasadena, lead author of the findings to be published April 20 in the Astrophysical Journal. "It's so hefty that the red dwarf, though larger in physical size, is circling around the white dwarf."

Kepler's primary job is to scan stars in search of orbiting planets. As the planets pass by, they block the starlight by miniscule amounts, which Kepler's sensitive detectors can see.

"The technique is equivalent to spotting a flea on a light bulb 3,000 miles away, roughly the distance from Los Angeles to New York City," said Avi Shporer, co-author of the study, also of Caltech.

Muirhead and his colleagues regularly use public Kepler data to search for and confirm planets around smaller stars, the red dwarfs, also known as M dwarfs. These stars are cooler and redder than our yellow sun. When the team first looked at the Kepler data for a target called KOI-256, they thought they were looking at a huge gas giant planet eclipsing the red dwarf.

"We saw what appeared to be huge dips in the light from the star, and suspected it was from a giant planet, roughly the size of Jupiter, passing in front," said Muirhead.

To learn more about the star system, Muirhead and his colleagues turned to the Hale Telescope at Palomar Observatory near San Diego. Using a technique called radial velocity, they discovered that the red dwarf was wobbling around like a spinning top. The wobble was far too big to be caused by the tug of a planet. That is when they knew they were looking at a massive white dwarf passing behind the red dwarf, rather than a gas giant passing in front.

The team also incorporated ultraviolet measurements of KOI-256 taken by the Galaxy Evolution Explorer (GALEX), a NASA space telescope now operated by the California Institute of Technology in Pasadena. The GALEX observations, led by Cornell University, Ithaca, N.Y., are part of an ongoing program to measure ultraviolet activity in all the stars in Kepler field of view, an indicator of potential habitability for planets in the systems. These data revealed the red dwarf is very active, consistent with being "spun-up" by the orbit of the more massive white dwarf.

The astronomers then went back to the Kepler data and were surprised by what they saw. When the white dwarf passed in front of its star, its gravity caused the starlight to bend and brighten by measurable effects.

"Only Kepler could detect this tiny, tiny effect," said Doug Hudgins, the Kepler program scientist at NASA Headquarters, Washington. "But with this detection, we are witnessing Einstein's theory of general relativity at play in a far-flung star system."

One of the consequences of Einstein's theory of general relativity is that gravity bends light. Astronomers regularly observe this phenomenon, often called gravitational lensing, in our galaxy and beyond. For example, the light from a distant galaxy can be bent and magnified by matter in front of it. This reveals new information about dark matter and dark energy, two mysterious ingredients in our universe.

Gravitational lensing has also been used to discover new planets and hunt for free-floating planets.

In the new Kepler study, scientists used the gravitational lensing to determine the mass of the white dwarf. By combining this information with all the data they acquired, the scientists were also able to measure accurately the mass of the red dwarf and the physical sizes of both stars. Kepler's data and Einstein's theory of relativity have together led to a better understanding of how binary stars evolve.

Other authors include Andrew Vanderburg of the University of California, Berkeley; Avi Shporer, Juliette Becker, Jonathan J. Swift, Sasha Hinkley, J. Sebastian Pineda, Michael Bottom, Christoph Baranec, Reed Riddle, Shriharsh P. Tendulkar, Khanh Bui, Richard Dekany and John Asher Johnson of Caltech; James P. Lloyd and Jim Fuller of Cornell University; Ming Zhao of The Pennsylvania State University, University Park; Andrew W. Howard of University of Hawaii, Hilo; Kaspar von Braun of the Max Planck Institute for Astronomy, Germany; Tabetha S. Boyajian of Yale University, New Haven, Conn.; Nicholas Law of the University of Toronto, Canada; A. N. Ramaprakash, Mahesh Burse, Pravin Chordia, Hillol Das and Sujit Punnadi of the Inter-University Centre for Astronomy & Astrophysics, India.

NASA Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace and Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with JPL at the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes the Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters. JPL is a division of Caltech. For more information about the Kepler mission, visit: http://www.nasa.gov/kepler .

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

Billions and Billions of Planets

A new analysis of data from NASA's Kepler mission finds evidence for at least 100 billion planets in our galaxy. Image credit: NASA/JPL-Caltech . › Full image and caption

Look up at the night sky and you'll see stars, sure. But the sky is also filled with planets -- billions and billions of them at least.
 

That's the conclusion of a new study by astronomers at the California Institute of Technology in Pasadena, which provides yet more evidence that planetary systems are the cosmic norm. The team made their estimate while analyzing planets orbiting a star called Kepler-32 -- planets that are representative, they say, of the vast majority of planets in our galaxy and thus serve as a perfect case study for understanding how most of these worlds form.
 

"There are at least 100 billion planets in the galaxy, just our galaxy," says John Johnson, assistant professor of planetary astronomy at Caltech and coauthor of the study, which was recently accepted for publication in the Astrophysical Journal. "That's mind-boggling."
 

"It's a staggering number, if you think about it," adds Jonathan Swift, a postdoctoral student at Caltech and lead author of the paper. "Basically, there's one of these planets per star."
 

The planetary system in question, which was detected by NASA's Kepler space telescope, contains five planets. Two of the planets orbiting Kepler-32 had previously been discovered by other astronomers. The Caltech team confirmed the remaining three, then analyzed the five-planet system and compared it to other systems found by Kepler.
 

The planets orbit a star that is an M dwarf -- a type that accounts for about three-quarters of all stars in the Milky Way. M-dwarf systems like Kepler-32's are quite different from our own solar system. For one, M dwarfs are cooler and much smaller than the sun. Kepler-32, for example, has half the mass of the sun and half its radius. The radii of its five planets range from 0.8 to 2.7 times that of Earth, and those planets orbit extremely close to their star. The whole Kepler-32 system fits within just over a tenth of an astronomical unit (the average distance between Earth and the sun) -- a distance that is about a third of the radius of Mercury's orbit around the sun.
 

The fact that M-dwarf systems vastly outnumber other kinds of systems carries a profound implication, according to Johnson, which is that our solar system is extremely rare. "It's just a weirdo," he says.
 

Read the full Caltech story at http://www.caltech.edu/content/planets-abound .
 

Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed the Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters in Washington.
 

For more information about NASA's Kepler mission, visit: http://www.nasa.gov/keplerhttp://www.nasa.gov/kepler .

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