Newly Discovered Twin Planets Could Solve Puffy Planet Mystery

Upper left: Schematic of the K2-132 system on the main sequence. Lower left: Schematic of the K2-132 system now. The host star has become redder and larger, irradiating the planet more and thus causing it to expand. Sizes not to scale.  Main panel: Gas giant planet K2-132b expands as its host star evolves into a red giant. The energy from the host star is transferred from the planet's surface to its deep interior, causing turbulence and deep mixing in the planetary atmosphere. The planet orbits its star every nine days and is located about 2000 light years away from us in the constellation Virgo.  Credit: Karen Teramura, UH IFA

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Maunakea, Hawaii - Since astronomers first measured the size of an extrasolar planet seventeen years ago, they have struggled to answer the question: how did the largest planets get to be so large? 

Thanks to the recent discovery of twin planets by a University of Hawaii Institute for Astronomy team led by graduate student Samuel Grunblatt, scientists are getting closer to an answer.

Gas giant planets are primarily made out of hydrogen and helium, and are at least four times the diameter of Earth. Gas giant planets that orbit scorchingly close to their host stars are known as "hot Jupiters." These planets have masses similar to Jupiter and Saturn, but tend to be much larger - some are puffed up to sizes even larger than the smallest stars.

The unusually large sizes of these planets are likely related to heat flowing in and out of their atmospheres, and several theories have been developed to explain this process. "However, since we don't have millions of years to see how a particular planetary system evolves, planet inflation theories have been difficult to prove or disprove," said Grunblatt.

To solve this issue, Grunblatt searched through data collected by NASA's K2 Mission to hunt for hot Jupiters orbiting red giant stars. These stars, which are in the late stages of their lives, become themselves significantly larger over their companion planet's lifetime. Following a theory put forth by Eric Lopez of NASA's Goddard Space Flight Center, hot Jupiters orbiting red giant stars should be highly inflated if direct energy input from the host star is the dominant process inflating planets.

The search has now revealed two planets, each orbiting their host star with a period of approximately nine days. Using stellar oscillations to precisely calculate the radii of both the stars and planets, the team found that the planets are 30 percent larger than Jupiter. 

Observations using the W. M. Keck Observatory on Maunakea, Hawaii also showed that, despite their large sizes, the planets were only half as massive as Jupiter. Remarkably, the two planets are near twins in terms of their orbital periods, radii, and masses.

Using models to track the evolution of the planets and their stars over time, the team calculated the planets' efficiency at absorbing heat from the star and transferring it to their deep interiors, causing the whole planet to expand in size and decrease in density. Their findings show that these planets likely needed the increased radiation from the red giant star to inflate, but the amount of radiation absorbed was also lower than expected.

It is risky to attempt to reach strong conclusions with only two examples. But these results begin to rule out some explanations of planet inflation, and are consistent with a scenario where planets are directly inflated by the heat from their host stars. The mounting scientific evidence seems to suggest that stellar radiation alone can directly alter the size and density of a planet.

Our own Sun will eventually become a red giant star, so it's important to quantify the effect its evolution will have on the rest of the Solar System. "Studying how stellar evolution affects planets is a new frontier, both in other solar systems as well as our own," said Grunblatt. "With a better idea of how planets respond to these changes, we can start to determine how the Sun's evolution will affect the atmosphere, oceans, and life here on Earth."

The search for gas giant planets around red giant stars continues since additional systems could conclusively distinguish between planet inflation scenarios. Grunblatt and his team have been awarded time with the NASA Spitzer Space Telescope to measure the sizes of these twin planets more accurately. In addition, the search for planets around red giants with the NASA K2 Mission will continue for at least another year, and NASA's Transiting Exoplanet Survey Satellite (TESS), launching in 2018, will observe hundreds of thousands of red giants across the entire sky.

"Seeing double with K2: Testing re-inflation with two remarkably similar planets orbiting red giant branch stars" has been published in November 27th edition of The Astronomical Journal as and is available online at http://iopscience.iop.org/article/10.3847/1538-3881/aa932d.

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Contacts

Sam Grunblatt
skg3@hawaii.edu
Cell: 845-430-4603

Dr. Daniel Huber
huberd@hawaii.edu
Office: 808-956-8573

Dr. Roy Gal
Media Contact
Office: 808-956-6235
Cell: 301-728-8637
rgal@ifa.hawaii.edu

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About W. M. Keck Observatory

The W. M. Keck Observatory telescopes are among the most scientifically productive on Earth. The two, 10-meter optical/infrared telescopes on the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometers, and world-leading laser guide star adaptive optics systems. 

Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c) 3 non-profit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.

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Article Summary

A University of Hawaii Institute for Astronomy-led team discovers unusually large twin exoplanets. Desipite their large sizes, observations using the W. M. Keck Observatory on Maunakea, Hawaii show that the planets are only half as massive as Jupiter. The discovery could help astronomers understand how the largest planets became so large.

Source: W.M. Keck Observatory

NASA Releases Kepler Survey Catalog with Hundreds of New Planet Candidates

NASA’s Kepler space telescope team has identified 219 new planet candidates, 10 of which are near-Earth size and in the habitable zone of their star.Credits: NASA/JPL-Caltech

NASA’s Kepler space telescope team has released a mission catalog of planet candidates that introduces 219 new planet candidates, 10 of which are near-Earth size and orbiting in their star's habitable zone, which is the range of distance from a star where liquid water could pool on the surface of a rocky planet.

This is the most comprehensive and detailed catalog release of candidate exoplanets, which are planets outside our solar system, from Kepler’s first four years of data. It’s also the final catalog from the spacecraft’s view of the patch of sky in the Cygnus constellation.

With the release of this catalog, derived from data publicly available on the NASA Exoplanet Archive, there are now 4,034 planet candidates identified by Kepler. Of which, 2,335 have been verified as exoplanets. Of roughly 50 near-Earth size habitable zone candidates detected by Kepler, more than 30 have been verified.

Additionally, results using Kepler data suggest two distinct size groupings of small planets. Both results have significant implications for the search for life. The final Kepler catalog will serve as the foundation for more study to determine the prevalence and demographics of planets in the galaxy, while the discovery of the two distinct planetary populations shows that about half the planets we know of in the galaxy either have no surface, or lie beneath a deep, crushing atmosphere – an environment unlikely to host life.

The findings were presented at a news conference Monday at NASA's Ames Research Center in California's Silicon Valley.

“The Kepler data set is unique, as it is the only one containing a population of these near Earth-analogs – planets with roughly the same size and orbit as Earth,” said Mario Perez, Kepler program scientist in the Astrophysics Division of NASA’s Science Mission Directorate. “Understanding their frequency in the galaxy will help inform the design of future NASA missions to directly image another Earth.”

The Kepler space telescope hunts for planets by detecting the minuscule drop in a star’s brightness that occurs when a planet crosses in front of it, called a transit.

This is the eighth release of the Kepler candidate catalog, gathered by reprocessing the entire set of data from Kepler’s observations during the first four years of its primary mission. This data will enable scientists to determine what planetary populations – from rocky bodies the size of Earth, to gas giants the size of Jupiter – make up the galaxy’s planetary demographics.

To ensure a lot of planets weren't missed, the team introduced their own simulated planet transit signals into the data set and determined how many were correctly identified as planets. Then, they added data that appear to come from a planet, but were actually false signals, and checked how often the analysis mistook these for planet candidates. This work told them which types of planets were overcounted and which were undercounted by the Kepler team’s data processing methods.

“This carefully-measured catalog is the foundation for directly answering one of astronomy’s most compelling questions – how many planets like our Earth are in the galaxy?” said Susan Thompson, Kepler research scientist for the SETI Institute in Mountain View, California, and lead author of the catalog study.

One research group took advantage of the Kepler data to make precise measurements of thousands of planets, revealing two distinct groups of small planets. The team found a clean division in the sizes of rocky, Earth-size planets and gaseous planets smaller than Neptune. Few planets were found between those groupings.

Using the W. M. Keck Observatory in Hawaii, the group measured the sizes of 1,300 stars in the Kepler field of view to determine the radii of 2,000 Kepler planets with exquisite precision.

“We like to think of this study as classifying planets in the same way that biologists identify new species of animals,” said Benjamin Fulton, doctoral candidate at the University of Hawaii in Manoa, and lead author of the second study. “Finding two distinct groups of exoplanets is like discovering mammals and lizards make up distinct branches of a family tree.”

It seems that nature commonly makes rocky planets up to about 75 percent bigger than Earth. For reasons scientists don't yet understand, about half of those planets take on a small amount of hydrogen and helium that dramatically swells their size, allowing them to "jump the gap" and join the population closer to Neptune’s size.

The Kepler spacecraft continues to make observations in new patches of sky in its extended mission, searching for planets and studying a variety of interesting astronomical objects, from distant star clusters to objects such as the TRAPPIST-1 system of seven Earth-size planets, closer to home.

Ames manages the Kepler missions for NASA’s Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

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

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Felicia Chou
Headquarters, Washington
202-358-0257
felicia.chou@nasa.gov

Michele Johnson
Ames Research Center, California’s Silicon Valley
650-604-6882
michele.johnson@nasa.gov

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

Editor: Karen Northon

Source: NASA/Kepler and K2

Kepler Mission Manager Update: K2 Marching On With Campaign 11

The comparison of two full frame images from the Kepler spacecraft show two black squares (Modules 3 and 7) and 19 red squares on the left. On the right, there are three black squares (Modules 3, 4 and 7) and 18 red squares. A red square indicates that data is being collected by the photometer and a black square indicates no data is being collected and that the module is no longer functional. Eighteen of the 21 science detector modules remain fully operational. Credits: NASA Ames/W. Stenzel

Natalie Batalha, astrophysicist and project scientist for NASA's Kepler Mission at NASA's Ames Research Center in Silicon Valley.  

Natalie Batalha

 

Jessie Dotson, astrophysicist and project scientist for NASA's K2 Mission at NASA's Ames Research Center in Silicon Valley.  

Jessie Dotson

 

Kepler’s K2 mission is now in the midst of its eleventh campaign, observing a patch of sky in the direction of the constellation Sagittarius. During this campaign, it will observe 14,250 new targets, including the Galactic Center and Saturn's moons Titan and Enceladus.

Campaign 11 began on Sept. 24, but was interrupted for three days (Oct. 18-20) to make a small pointing correction to accommodate the imbalance that was created by broadcasting data from a different antenna on the other side of the spacecraft. Although the spacecraft is as big and heavy as an SUV, it actually turns slightly when we change the broadcasting antenna. This is like having your car begin to turn from the force of the blinking of your turn signal. Yes, the spacecraft is that delicately balanced! Data collection for Campaign 11 will continue until Dec. 7.

Since my last update, our investigation into the cause of the spacecraft's photometer—the onboard camera—being powered off in July during Campaign 10, confirms that that science detector Module 4 failed. The likely cause was a random part failure that resulted in a high electric current in the circuitry, which blew the protection fuse, disabling the detector but preventing the problem from propagating to other detectors. As part of the fault protection response, the photometer was powered off.

Eighteen of the 21 science detector modules remain fully operational. Two science modules had failed previously: Module 7 in January 2014 and Module 3 in January 2010. These are not unexpected events as the spacecraft ages in the harsh environment of space.

In September, the spacecraft had a unique opportunity to provide a 'wide-angle' view of comet 67P/Churyumov–Gerasimenko, making observations of its core and tail. These observations complement the close-in study of the comet provided by the European Space Agency's Rosetta spacecraft during the final month of its mission. These and the remainder of Campaign 10 data have been downlinked to the ground and are being processed for release at the public archive later this month.

 

We've also made changes with the Kepler and K2 project scientist personnel. On Aug. 15, Natalie Batalha was appointed as the project scientist for the Kepler mission. Since 1999, Natalie has served in numerous leadership roles throughout the mission including deputy principal investigator and science team lead. In addition to her responsibilities with the Kepler mission, Natalie is a co-lead of NASA's Nexus for Exoplanet System Science Coalition, and serves on the James Webb Space Telescope Advisory Committee. She also serves as a member of the NASA Advisory Council's Astrophysics Subcommittee, and, in 2013, participated on the task force to define NASA's 30-year Astrophysics Roadmap- Enduring Quests, Daring Visions: NASA Astrophysics in the Next Three Decades.

On Sept. 6, Jessie Dotson assumed the role of project scientist for the K2 mission. Dr. Dotson was formerly the deputy science office director for Kepler and, in 2011, established the Kepler Guest Observer Office. Most recently, she served as astrophysics branch chief in the Space Science and Astrobiology Division at NASA Ames. In 2014, Jessie helped formulate the Asteroid Threat Assessment Project (ATAP) at NASA Ames to quantify the risk to Earth of an asteroid impact. She currently leads the ATAP asteroid characterization team. In 2016, Jessie was awarded a NASA Outstanding Leadership Medal for her work as the astrophysics branch chief at Ames.

Together, Natalie and Jessie replace Steve Howell who served as Kepler project scientist since 2010 and K2 project scientist since mission conception in 2013. In that role, Steve oversaw Kepler science operations through the end of its prime mission, the recovery from the reaction wheel failure that nearly ended the mission, and the development and implementation of the K2 mission that gave Kepler a new lease on life. We commend Steve for his work as the Kepler/K2 project scientist, with notable leadership in catalyzing the science community to support Kepler's extended mission called K2.

In August, the team gathered for the annual year-in-review of spacecraft operations with Ball Aerospace, the designer, manufacturer and flight controller of Kepler. A topic of high interest is the on-board fuel reserve, which is expected to last into the spring of 2018.

At last count, Kepler has identified more than 5,100 planet candidates. Of these, more than 2,500 have been verified as bona fide planets. NASA’s next planet-hunting mission, the Transiting Exoplanet Survey Satellite (TESS), is scheduled to launch no later than June 2018. TESS will build upon Kepler’s success and search for exoplanets around the stars closest to the own solar system.

Regards,


Charlie Sobeck​
Kepler and K2 mission manager
NASA's Ames Research Center 
 

 

Editor: Michele Johnson

 

 

Source: NASA/Kepler and K2 

Kepler Watches Stellar Dancers in the Pleiades Cluster

This image shows the Pleiades cluster of stars as seen through the eyes of WISE, or NASA's Wide-field Infrared Survey Explorer. Credits: NASA/JPL-Caltech/UCLA. Full image and caption

Like cosmic ballet dancers, the stars of the Pleiades cluster are spinning. But these celestial dancers are all twirling at different speeds. Astronomers have long wondered what determines the rotation rates of these stars.

By watching these stellar dancers, NASA's Kepler space telescope during its K2 mission has helped amass the most complete catalog of rotation periods for stars in a cluster. This information can help astronomers gain insight into where and how planets form around these stars, and how such stars evolve.    

"We hope that by comparing our results to other star clusters, we will learn more about the relationship between a star’s mass, its age, and even the history of its solar system," said Luisa Rebull, a research scientist at the Infrared Processing and Analysis Center at Caltech in Pasadena, California. She is the lead author of two new papers and a co-author on a third paper about these findings, all being published in the Astronomical Journal.

The Pleiades star cluster is one of the closest and most easily seen star clusters, residing just 445 light-years away from Earth, on average. At about 125 million years old, these stars -- known individually as Pleiads -- have reached stellar "young adulthood." In this stage of their lives, the stars are likely spinning the fastest they ever will.

As a typical star moves further along into adulthood, it loses some zip due to the copious emission of charged particles known as a stellar wind (in our solar system, we call this the solar wind). The charged particles are carried along the star’s magnetic fields, which overall exerts a braking effect on the rotation rate of the star.

Rebull and colleagues sought to delve deeper into these dynamics of stellar spin with Kepler. Given its field of view on the sky, Kepler observed approximately 1,000 stellar members of the Pleiades over the course of 72 days. The telescope measured the rotation rates of more than 750 stars in the Pleiades, including about 500 of the lowest-mass, tiniest, and dimmest cluster members, whose rotations could not previously be detected from ground-based instruments.

Kepler measurements of starlight infer the spin rate of a star by picking up small changes in its brightness. These changes result from "starspots" which, like the more-familiar sunspots on our sun, form when magnetic field concentrations prevent the normal release of energy at a star’s surface. The affected regions become cooler than their surroundings and appear dark in comparison.

As stars rotate, their starspots come in and out of Kepler’s view, offering a way to determine spin rate. Unlike the tiny, sunspot blemishes on our middle-aged sun, starspots can be gargantuan in stars as young as those in the Pleiades because stellar youth is associated with greater turbulence and magnetic activity. These starspots trigger larger brightness decreases, and make spin rate measurements easier to obtain.

During its observations of the Pleiades, a clear pattern emerged in the data: More massive stars tended to rotate slowly, while less massive stars tended to rotate rapidly. The big-and-slow stars' periods ranged from one to as many as 11 Earth-days. Many low-mass stars, however, took less than a day to complete a pirouette. (For comparison, our sedate sun revolves fully just once every 26 days.) The population of slow-rotating stars includes some ranging from a bit larger, hotter and more massive than our sun, down to other stars that are somewhat smaller, cooler and less massive. On the far end, the fast-rotating, fleet-footed, lowest-mass stars possess as little as a tenth of our sun’s mass. 

"In the 'ballet' of the Pleiades, we see that slow rotators tend to be more massive, whereas the fastest rotators tend to be very light stars," said Rebull.  

The main source of these differing spin rates is the internal structure of the stars, Rebull and colleagues suggest. Larger stars have a huge core enveloped in a thin layer of stellar material undergoing a process called convection, familiar to us from the circular motion of boiling water.

Small stars, on the other hand, consist almost entirely of convective, roiling regions. As stars mature, the braking mechanism from magnetic fields more easily slows the spin rate of the thin, outermost layer of big stars than the comparatively thick, turbulent bulk of small stars.

Thanks to the Pleiades’ proximity, researchers think it should be possible to untangle the complex relationships between stars’ spin rates and other stellar properties. Those stellar properties, in turn, can influence the climates and habitability of a star’s hosted exoplanets. For instance, as spinning slows, so too does starspot generation, and the solar storms associated with starspots. Fewer solar storms means less intense, harmful radiation blasting into space and irradiating nearby planets and their potentially emerging biospheres.    

"The Pleiades star cluster provides an anchor for theoretical models of stellar rotation going both directions, younger and older," said Rebull. "We still have a lot we want to learn about how, when and why stars slow their spin rates and hang up their 'dance shoes,' so to speak."

Rebull and colleagues are now analyzing K2 mission data from an older star cluster, Praesepe, popularly known as the Beehive Cluster, to further explore this phenomenon in stellar structure and evolution.

"We’re really excited that K2 data of star clusters, such as the Pleiades, have provided astronomers with a bounty of new information and helped advance our knowledge of how stars rotate throughout their lives," said Steve Howell, project scientist for the K2 mission at NASA’s Ames Research Center in Moffett Field, California.

The K2 mission’s approach to studying stars employs the Kepler spacecraft's ability to precisely observe miniscule changes in starlight. Kepler’s primary mission ended in 2013, but more exoplanet and astrophysics observations continue with the K2 mission, which began in 2014.

Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

Michele Johnson
Ames Research Center, Moffett Field, Calif.

650-604-6982
michele.johnson@nasa.gov


Written by Adam Hadhazy

Editor: Tony Greicius

Source: NASA/Kepler and K2

Astronomers Catalog Planets That May Be Earthlike

The artistic concept of Kepler-186f is the result of scientists and artists collaborating to imagine the appearance of these distant worlds. 

Image credit: NASA Ames/SETI Institute/JPL-Caltech.  › Full image and caption

Using public data collected by NASA's Kepler mission, astronomers have catalogued the planet candidates that may be similar to our third rock from the sun. The tabulation of candidates will help astronomers focus their research efforts in the search for life.

The analysis, led by Stephen Kane, an associate professor of physics and astronomy at San Francisco State University in California, highlights 20 candidates in the Kepler trove that are less than twice the size of Earth and orbit their star in the conservative habitable zone -- the range of distances where liquid water could pool on the surface of an orbiting planet. Of these 20 candidates, nine have been previously investigated and determined to be verified planets, including notables like Kepler-62f, Kepler-186f, Kepler-283c, Kepler-296f and Kepler-442b.

The results are presented in a paper accepted by the Astrophysical Journal. For a listing of the candidates and their properties, the paper can be reviewed at: http://arxiv.org/abs/1608.00620.

NASA's Ames Research Center in California's Silicon Valley manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.

News Media Contact

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

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

Written by Michele Johnson

Source: JPL-Caltech

NASA's K2 Finds Newborn Exoplanet Around Young Star

When a planet such as K2-33b passes in front of its host star, it blocks some of the star's light. Observing this periodic dimming, called a transit, from continual monitoring of a star's brightness, allows astronomers to detect planets outside our solar system with a high degree of certainty. This Neptune-sized planet orbits a star that is between 5 and 10 million years old. In addition to the planet, the star hosts a disk of planetary debris, seen as a bright ring encircling the star. Youtube

K2-33b, shown in this illustration, is one of the youngest exoplanets detected to date. It makes a complete orbit around its star in about five days. 
Credits: NASA/JPL-Caltech.

This image shows the K2-33 system, and its planet K2-33b, compared to our own solar system. The planet has a five-day orbit, whereas Mercury orbits our sun in 88 days. The planet is also nearly 10 times closer to its star than Mercury is to the sun. Credits: NASA/JPL-Caltech

Astronomers have discovered the youngest fully formed exoplanet ever detected. The discovery was made using NASA's Kepler Space Telescope and its extended K2 mission, as well as the W. M. Keck Observatory on Mauna Kea, Hawaii. Exoplanets are planets that orbit stars beyond our sun.

The newfound planet, K2-33b, is a bit larger than Neptune and whips tightly around its star every five days. It is only 5 to 10 million years old, making it one of a very few newborn planets found to date.

"Our Earth is roughly 4.5 billion years old," said Trevor David of Caltech in Pasadena, lead author of a new study published online June 20, 2016, in the journal Nature. "By comparison, the planet K2-33b is very young. You might think of it as an infant." David is a graduate student working with astronomer Lynne Hillenbrand, also of Caltech.

Planet formation is a complex and tumultuous process that remains shrouded in mystery. Astronomers have discovered and confirmed roughly 3,000 exoplanets so far; however, nearly all of them are hosted by middle-aged stars, with ages of a billion years or more. For astronomers, attempting to understand the life cycles of planetary systems using existing examples is like trying to learn how people grow from babies to children to teenagers, by only studying adults.

"The newborn planet will help us better understand how planets form, which is important for understanding the processes that led to the formation of Earth," said co-author Erik Petigura of Caltech.

The first signals of the planet's existence were measured by K2. The telescope's camera detected a periodic dimming of the light emitted by the planet's host star, a sign that an orbiting planet could be regularly passing in front of the star and blocking the light. Data from the Keck Observatory validated that the dimming was indeed caused by a planet, and also helped confirm its youthful age.

Infrared measurements from NASA's Spitzer Space Telescope showed that the system's star is surrounded by a thin disk of planetary debris, indicating that its planet-formation phase is wrapping up. Planets form out of thick disks of gas and dust, called protoplanetary disks, that surround young stars.

"Initially, this material may obscure any forming planets, but after a few million years, the dust starts to dissipate," said co-author Anne Marie Cody, a NASA Postdoctoral Program fellow at NASA's Ames Research Center in California's Silicon Valley. "It is during this time window that we can begin to detect the signatures of youthful planets with K2." 

A surprising feature in the discovery of K2-33b is how close the newborn planet lies to its star. The planet is nearly 10 times closer to its star than Mercury is to our sun, making it hot. While numerous older exoplanets have been found orbiting very tightly to their stars, astronomers have long struggled to understand how more massive planets like this one wind up in such small orbits. Some theories propose that it takes hundreds of millions of years to bring a planet from a more distant orbit into a close one -- and therefore cannot explain K2-33b, which is quite a bit younger.

The science team says there are two main theories that may explain how K2-33b wound up so close to its star. It could have migrated there in a process called disk migration that takes hundreds of thousands of years. Or, the planet could have formed "in situ" -- right where it is. The discovery of K2-33b therefore gives theorists a new data point to ponder.

"After the first discoveries of massive exoplanets on close orbits about 20 years ago, it was immediately suggested that they could absolutely not have formed there, but in the past several years, some momentum has grown for in situ formation theories, so the idea is not as wild as it once seemed," said David.

"The question we are answering is: Did those planets take a long time to get into those hot orbits, or could they have been there from a very early stage? We are saying, at least in this one case, that they can indeed be there at a very early stage," he said.

Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

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

Felicia Chou
NASA Headquarters, Washington
202-358-0257
felicia.chou@nasa.gov

Written by Whitney Clavin
Editor: Tony Greicius

Source: NASA/Kepler and K2

2007 OR10: Largest Unnamed World in the Solar System

New K2 results peg 2007 OR10 as the largest unnamed body in our solar system and the third largest of the current roster of about half a dozen dwarf planets. The revised measurement of 2007 OR10's diameter, 955 miles (1,535 kilometers), is about 60 miles (100 kilometers) greater than the next largest dwarf planet, Makemake, or about one-third smaller than Pluto. Another dwarf planet, named Haumea, has an oblong shape that is wider on its long axis than 2007 OR10, but its overall volume is smaller Credits: Konkoly Observatory/András Pál, Hungarian Astronomical Association/Iván Éder, NASA/JHUAPL/SwRI. Hi-res image

Dwarf planets tend to be a mysterious bunch. With the exception of Ceres, which resides in the main asteroid belt between Mars and Jupiter, all members of this class of minor planets in our solar system lurk in the depths beyond Neptune. They are far from Earth – small and cold – which makes them difficult to observe, even with large telescopes. So it's little wonder astronomers only discovered most of them in the past decade or so.

Pluto is a prime example of this elusiveness. Before NASA's New Horizons spacecraft visited it in 2015, the largest of the dwarf planets had appeared as little more than a fuzzy blob, even to the keen-eyed Hubble Space Telescope. Given the inherent challenges in trying to observe these far-flung worlds, astronomers often need to combine data from a variety of sources in order to tease out basic details about their properties.

Recently, a group of astronomers did just that by combining data from two space observatories to reveal something surprising: a dwarf planet named 2007 OR10 is significantly larger than previously thought.

The results peg 2007 OR10 as the largest unnamed world in our solar system and the third largest of the current roster of about half a dozen dwarf planets. The study also found that the object is quite dark and rotating more slowly than almost any other body orbiting our sun, taking close to 45 hours to complete its daily spin.

For their research, the scientists used NASA's repurposed planet-hunting Kepler space telescope -- its mission now known as K2 -- along with the archival data from the infrared Herschel Space Observatory. Herschel was a mission of the European Space Agency (ESA) with NASA participation.

The research paper reporting these results is published in The Astronomical Journal.

"K2 has made yet another important contribution in revising the size estimate of 2007 OR10. But what's really powerful is how combining K2 and Herschel data yields such a wealth of information about the object's physical properties," said Geert Barentsen, Kepler/K2 research scientist at NASA's Ames Research Center in California's Silicon Valley.

The revised measurement of the planet's diameter, 955 miles (1,535 kilometers), is about 60 miles (100 kilometers) greater than the next largest dwarf planet, Makemake, or about one-third smaller than Pluto. Another dwarf planet, named Haumea, has an oblong shape that is wider on its long axis than 2007 OR10, but its overall volume is smaller.

Like its predecessor mission, K2 searches for the change in brightness of distant objects. The tiny, telltale dip in the brightness of a star can be the signature of a planet passing or transiting in front.

But, closer to home, K2 also looks out into our solar system to observe small bodies such as comets, asteroids, moons and dwarf planets. Because of its exquisite sensitivity to small changes in brightness, the Kepler spacecraft is an excellent instrument for observing the brightness of distant solar system objects and how that changes as they rotate.

Figuring out the size of small, faint objects far from Earth is tricky business. Since they appear as mere points of light, it can be a challenge to determine whether the light they emit represents a smaller, brighter object, or a larger, darker one. This is what makes it so difficult to observe 2007 OR10 -- although its elliptical orbit brings it nearly as close to the sun as Neptune, it is currently twice as far from the sun as Pluto.

Enter the dynamic duo of Kepler and Herschel.

Previous estimates based on Herschel data alone suggested a diameter of roughly 795 miles (1,280 kilometers) for 2007 OR10. However, without a handle on the object's rotation period, those studies were limited in their ability to estimate its overall brightness, and hence its size. The discovery of the very slow rotation by K2 was essential for the team to construct more detailed models that revealed the peculiarities of this dwarf planet. The rotation measurements even included hints of variations in brightness across its surface.

Together, the two space telescopes allowed the team to measure the fraction of sunlight reflected by 2007 OR10 (using Kepler) and the fraction absorbed and later radiated back as heat (using Herschel). Putting these two data sets together provided an unambiguous estimation of the dwarf planet's size and how reflective it is.

According to the new measurements, the diameter of 2007 OR10 is some 155 miles (250 kilometers) larger than previously thought. The larger size also implies higher gravity and a very dark surface -- the latter because the same amount of light is being reflected by a larger body. This dark nature is different from most dwarf planets, which are much brighter. Previous ground-based observations found 2007 OR10 has a characteristic red color, and other researchers have suggested this might be due to methane ices on its surface.

"Our revised larger size for 2007 OR10 makes it increasingly likely the planet is covered in volatile ices of methane, carbon monoxide and nitrogen, which would be easily lost to space by a smaller object," said András Pál at Konkoly Observatory in Budapest, Hungary, who led the research. "It's thrilling to tease out details like this about a distant, new world -- especially since it has such an exceptionally dark and reddish surface for its size."

As for when 2007 OR10 will finally get a name, that honor belongs to the object's discoverers. Astronomers Meg Schwamb, Mike Brown and David Rabinowitz spotted it in 2007 as part of a survey to search for distant solar system bodies using the Samuel Oschin Telescope at Palomar Observatory near San Diego, California.

"The names of Pluto-sized bodies each tell a story about the characteristics of their respective objects. In the past, we haven't known enough about 2007 OR10 to give it a name that would do it justice," said Schwamb. "I think we're coming to a point where we can give 2007 OR10 its rightful name."

Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

For more information about the Kepler and K2 missions, visit: http://www.nasa.gov/kepler

More information about Herschel is online at: http://www.nasa.gov/herschel

2007 OR10, the largest unnamed body in the solar system, was visible during the K2 mission's campaign three for 19 days in late 2014. K2 is the new mission of Kepler spacecraft. The apparent movement of the faint dwarf planet (indicated with the arrow) among the stars is caused by the changing position of Kepler as it orbits around the sun. The diffuse light sweeping across is a reflection from the much brighter planet Mars passing nearby. Credits: Konkoly Observatory/László Molnár and András Pál. Youtube

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Media Contact:

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

Written by Preston Dyches

Last Updated: May 11, 2016

Editor: Michele Johnson

Source: NASA/Kepler and K2

Caught For The First Time: The Early Flash Of An Exploding Star

The brilliant flash of an exploding star’s shockwave—what astronomers call the “shock breakout” -- is illustrated in this video animation. The cartoon video begins with a view of a red supergiant star that is 500 hundred times bigger and 20,000 brighter than our sun. When the star’s internal furnace can no longer sustain nuclear fusion its core to collapses under gravity. A shockwave from the implosion rushes upward through the star’s layers. The shockwave initially breaks through the star’s visible surface as a series of finger-like plasma jets. Only 20 minute later the full fury of the shockwave reaches the surface and the doomed star blasts apart as a supernova explosion. This animation is based on photometric observations made by NASA’s Kepler space telescope. By closely monitoring the star KSN 2011d, located 1.2 billion light-years away, Kepler caught the onset of the early flash and subsequent explosion. Credits: Credit: NASA Ames, STScI/G. Bacon.  Youtube

The diagram illustrates the brightness of a supernova event relative to the sun as it unfolds. For the first time, a supernova shockwave has been observed in the optical wavelength or visible light as it reaches the surface of the star. This early flash of light is called a shock breakout. The explosive death of this star, called KSN 2011d, as it reaches its maximum brightness takes 14 days. The shock breakout itself lasts only about 20 minutes, so catching the flash of energy is an investigative milestone for astronomers. The unceasing gaze of NASA's Kepler space telescope allowed astronomers to see, at last, this early moment as the star blows itself to bits. Supernovae like these — known as Type II — begin when the internal furnace of a star runs out of nuclear fuel causing its core to collapse as gravity takes over. This type of star is called a red supergiant star and it is 20,000 times brighter than our sun. As the supergiant star goes supernova, the energy traveling from the core reaches the surfaces with a burst of light that is 130,000,000 times brighter than the sun. The star continues to explode and grow reaching maximum brightness that is about 1,000,000,000 times brighter than the sun. Credits: NASA Ames/W. Stenzel

The brilliant flash of an exploding star’s shockwave—what astronomers call the “shock breakout”—has been captured for the first time in the optical wavelength or visible light by NASA's planet-hunter, the Kepler space telescope. 

An international science team led by Peter Garnavich, an astrophysics professor at the University of Notre Dame in Indiana, analyzed light captured by Kepler every 30 minutes over a three-year period from 500 distant galaxies, searching some 50 trillion stars. They were hunting for signs of massive stellar death explosions known as supernovae.

In 2011, two of these massive stars, called red supergiants, exploded while in Kepler’s view. The first behemoth, KSN 2011a, is nearly 300 times the size of our sun and a mere 700 million light years from Earth. The second, KSN 2011d, is roughly 500 times the size of our sun and around 1.2 billion light years away.
“To put their size into perspective, Earth's orbit about our sun would fit comfortably within these colossal stars,” said Garnavich.

Whether it’s a plane crash, car wreck or supernova, capturing images of sudden, catastrophic events is extremely difficult but tremendously helpful in understanding root cause. Just as widespread deployment of mobile cameras has made forensic videos more common, the steady gaze of Kepler allowed astronomers to see, at last, a supernova shockwave as it reached the surface of a star. The shock breakout itself lasts only about 20 minutes, so catching the flash of energy is an investigative milestone for astronomers.

“In order to see something that happens on timescales of minutes, like a shock breakout, you want to have a camera continuously monitoring the sky,” said Garnavich. “You don’t know when a supernova is going to go off, and Kepler's vigilance allowed us to be a witness as the explosion began.”

Supernovae like these — known as Type II — begin when the internal furnace of a star runs out of nuclear fuel causing its core to collapse as gravity takes over.

The two supernovae matched up well with mathematical models of Type II explosions reinforcing existing theories. But they also revealed what could turn out to be an unexpected variety in the individual details of these cataclysmic stellar events.

While both explosions delivered a similar energetic punch, no shock breakout was seen in the smaller of the supergiants. Scientists think that is likely due to the smaller star being surrounded by gas, perhaps enough to mask the shockwave when it reached the star's surface.

“That is the puzzle of these results,” said Garnavich. “You look at two supernovae and see two different things. That’s maximum diversity.”

Understanding the physics of these violent events allows scientists to better understand how the seeds of chemical complexity and life itself have been scattered in space and time in our Milky Way galaxy

"All heavy elements in the universe come from supernova explosions. For example, all the silver, nickel, and copper in the earth and even in our bodies came from the explosive death throes of stars," said Steve Howell, project scientist for NASA's Kepler and K2 missions at NASA’s Ames Research Center in California's Silicon Valley. "Life exists because of supernovae."

Garnavich is part of a research team known as the Kepler Extragalactic Survey or KEGS. The team is nearly finished mining data from Kepler’s primary mission, which ended in 2013 with the failure of reaction wheels that helped keep the spacecraft steady. However, with the reboot of the Kepler spacecraft as NASA's K2 mission, the team is now combing through more data hunting for supernova events in even more galaxies far, far away.

"While Kepler cracked the door open on observing the development of these spectacular events, K2 will push it wide open observing dozens more supernovae," said Tom Barclay, senior research scientist and director of the Kepler and K2 guest observer office at Ames. "These results are a tantalizing preamble to what's to come from K2!"

In addition to Notre Dame, the KEGS team also includes researchers from the University of Maryland in College Park; the Australian National University in Canberra, Australia; the Space Telescope Science Institute in Baltimore, Maryland; and the University of California, Berkeley.

The research paper reporting this discovery has been accepted for publication in the Astrophysical Journal.

Ames manages the Kepler and K2 missions for NASA’s Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

Authored by H. Pat Brennan/JPL and Michele Johnson/Ames

 Media contact: 

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

Source: NASA/Kepler and K2