Kepler Planet Count

Confirmed Planets: 1,004
Planet Candidates: 4,175
Eclipsing Binary Stars: 2,165
View Discovery Table

. Kepler Mission Manager Update

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 Kepler Mission Manager Update 

The artist's concept depicts Kepler-186f , the first validated Earth-size planet to orbit a distant star in the habitable zone 

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. 

The Kepler team today reports on four years of ground-based follow-up observations targeting Kepler's exoplanet systems at the American Astronomical ...

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 Kepler Team Soliciting Community Input for Alternate Science Investigations for the Kepler Spacecraft

Kepler has lost the use of two of its four reaction wheels. These reaction wheels were used to keep the telescope in fine point during long duration (weeks to months) observations of the Kepler field of view. Kepler requires three reaction wheels to deliver the high-precision photometry necessary for small exoplanet detection. If one of the two reaction wheels cannot be returned to operation, it is unlikely that the spacecraft will resume the nominal Kepler exoplanet and astrophysics mission. NASA has announced a call for white papers to solicit community input for alternate science investigations that may be performed using Kepler and are consistent with its probable two-wheel performance. If an appropriate science case(s) and cost envelope is found, the repurposed mission will continue to be operated out of NASA Ames Research Center and make use of the nominal mission project office personnel and expertise already in place. The call for white papers and initial information as to the preliminary assessment of the pointing ability of the Kepler spacecraft using only two reaction wheels are provided. .

MOFFETT FIELD, Calif. -- NASA's Kepler mission scientists have discovered a new planetary system that is home to the smallest planet yet found around a star similar to our sun.

The planets are located in a system called Kepler-37, about 210 light-years from Earth in the constellation Lyra. The smallest planet, Kepler-37b, is slightly larger than our moon, measuring about one-third the size of Earth. It is smaller than Mercury, which made its detection a challenge. 

Using publicly available data from NASA’s Kepler space telescope, astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) estimate that six percent of red dwarf stars in the galaxy have Earth-size planets in the "habitable zone," the range of distances from a star where the surface temperature of an orbiting planet might be suitable for liquid water.

The majority of the sun's closest stellar neighbors are red dwarfs. Researchers now believe that an Earth-size planet with a moderate temperature may be just 13 light-years away.

"We don't know if life could exist on a planet orbiting a red dwarf, but the findings pique my curiosity and leave me wondering if the cosmic cradles of life are more diverse than we humans have imagined," said Natalie Batalha, Kepler mission scientist, NASA's Ames Research Center in Moffett Field, Calif. 

News release: 2012-359                                                                       Nov. 14, 2012

NASA's Kepler Wraps Prime Mission, Begins Extension

The full version of this story with accompanying images is at:

PASADENA, Calif. -- NASA is marking two milestones in the search for planets like Earth; the successful completion of the Kepler Space Telescope's three-and-a-half-year prime mission and the beginning of an extended mission that could last as long as four years.

Scientists have used Kepler data to identify more than 2,300 planet candidates and confirm more than 100 planets. Kepler is teaching us that the galaxy is teeming with planetary systems and that planets are prolific, and is giving us hints that nature makes small planets efficiently.

So far, hundreds of Earth-size planet candidates have been found, as well as candidates that orbit in the habitable zone, the region in a planetary system where liquid water might exist on the surface of a planet. None of the candidates is exactly like Earth. With the completion of its prime mission, Kepler now has collected enough data to begin finding true sun-Earth analogs -- Earth-size planets with a one-year orbit around stars similar to the sun.

"The initial discoveries of the Kepler mission indicate at least a third of the stars have planets and the number of planets in our galaxy must number in the billions," said William Borucki, Kepler principal investigator at NASA's Ames Research Center in Moffett Field, Calif. "The planets of greatest interest are other Earths, and these could already be in the data awaiting analysis. Kepler's most exciting results are yet to come."

NASA's Kepler Space Telescope searches for planet candidates orbiting distant suns, or exoplanets, by continuously measuring the brightness of more than 150,000 stars. When a planet candidate passes, or transits, in front of the star from the spacecraft's vantage point, light from the star is blocked. Different-sized planets block different amounts of starlight. The amount of starlight blocked by a planet reveals its size relative to its star.

Kepler was launched March 6, 2009. Its mission was to survey a portion of the galaxy to determine what fraction of stars might harbor potentially habitable, Earth-sized planets. Planets orbiting in or near habitable zones are of particular interest.

Kepler began the search for small worlds like our own on May 12, 2009, after two months of commissioning. Within months, five exoplanets, known as hot Jupiters because of their enormous size and orbits close to their stars, were confirmed.

Results from Kepler data continue to expand our understanding of planets and planetary systems. Highlights from the prime mission include:

-- In August 2010, scientists confirmed the discovery of the first planetary system with more than one planet transiting the same star. The Kepler-9 system opened the door to measurement of gravitational interactions between planets as observed by the variations in their transit timing. This powerful new technique enables astronomers, in many cases, to calculate the mass of planets directly from Kepler data, without the need for follow-up observations from the ground.

-- In January 2011, the Kepler team announced the discovery of the first unquestionably rocky planet outside the solar system. Kepler-10b, measuring 1.4 times the size of Earth, is the smallest confirmed planet with both a radius and mass measurement. Kepler has continued to uncover smaller and smaller planets, some almost as small as Mars, which tells us small rocky worlds may be common in the galaxy.

-- In February 2011, scientists announced Kepler had found a very crowded and compact planetary system -- a star with multiple transiting planets. Kepler-11 has six planets larger than Earth, all orbiting closer to their star than Venus orbits our sun. This and other subsequently identified compact, multi-planet systems have orbital spacing relative to their host sun and neighboring planets unlike anything envisioned prior to the mission.

-- In September 2011, Kepler data confirmed the existence of a world with a double sunset like the one famously portrayed in the film "Star Wars" more than 35 years ago. The discovery of Kepler-16b turned science fiction into science fact. Since then, the discoveries of six additional worlds orbiting double stars further demonstrated planets can form and persist in the environs of a double-star system.

-- In December 2011, NASA announced Kepler's discovery of the mission's first planet in a habitable zone. Kepler-22b, about 2.4 times the size of Earth, is the smallest-radius planet yet found to orbit a sun-like star in the habitable zone. This discovery confirmed that we are getting continually closer to finding planets like our own.

-- In February 2012, the Kepler team announced more than 1,000 new transiting planet candidates for a cumulative total of 2,321. The data continue the trend toward identifying smaller planets at longer orbital periods, similar to Earth. The results include hundreds of planetary systems.

-- Recently, citizen scientists participating in Planet Hunters, a program led by Yale University, New Haven, Conn., that enlists the public to comb through Kepler data for signs of transiting planets, made their first planet discovery. The joint effort of amateur astronomers and scientists led to the first reported case of a planet orbiting a double star. The three bodies are, in turn, being orbited by a second distant pair of stars.

"Kepler's bounty of new planet discoveries, many quite different from anything found previously, will continue to astound," said Jack Lissauer, planetary scientist at Ames. "But to me, the most wonderful discovery of the mission has not been individual planets, but the systems of two, three, even six planets crowded close to their stars, and, like the planets orbiting about our sun, moving in nearly the same plane. Like people, planets interact with their neighbors and can be greatly affected by them. What are the neighborhoods of Earth-size exoplanets like? This is the question I most hope Kepler will answer in the years to come."

In April 2012, NASA awarded Kepler an extended mission through as late as 2016. More time will enable the continued search for worlds like our own -- worlds that are not too far and too close to their sun.

"The Earth isn't unique, nor the center of the universe," said Geoff Marcy, professor of astronomy at the University of California at Berkeley. "The diversity of other worlds is greater than depicted in all the science fiction novels and movies. Aristotle would be proud of us for answering some of the most profound philosophical questions about our place in the universe."

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: .

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.

Michele Johnson 650-604-4789
Ames Research Center, Moffett Field, Calif.

J.D. Harrington 202-358-5241
Headquarters, Washington

- end -

Since the last mission update the Kepler team has completed two science data downloads. The most recent data download on Oct. 5, 2012 included a quarterly roll to the fall science attitude. This marked the successful completion of Quarter 14 flight operations and the beginning of Quarter 15.

The spacecraft's performance continues to be excellent while operating on three reaction wheels. Analysis of the telemetry has revealed no new cause for concern regarding the remaining wheels, and engineers continue to take steps to assure their continued performance.

The Kepler spacecraft trails Earth in a drift-away heliocentric orbit and is currently 42 million miles away. Unlike NASA's Hubble space telescope, the spacecraft is not accessible for a servicing mission.

Kepler Mission Manager Update  10.14.2012

Recently, more discovery announcements were made-

  • The Kepler-47 system  was announced on August 28. This is another Kepler first– a circumbinary system with more than one transiting planet, one of which is in the habitable zone of its parent binary star system.
  • 41 New Transiting Planets. Two newly submitted studies verify 41 new transiting planets in 20 star systems. These results may increase the number of Kepler’s confirmed planets by more than 50 percent to nearly 120 planets hosted in nearly 70 systems, over half of which contain more than one planet. The papers are currently under scientific peer-review.

The Kepler team completed another monthly science data download over August 29-30, 2012. This marked the completion of Quarter 14 month 2 science data collection. 

Since the apparent failure of reaction wheel #2 in mid-July, the spacecraft's performance has been excellent while operating on three reaction wheels. While still undetermined, the reaction wheel is believed to have suffered an internal hardware failure and is likely irrecoverable. Analysis of telemetry will continue, but additional troubleshooting is not anticipated on the wheel unless further problems warrant. Meanwhile, engineers are taking steps to assure the continued performance of the remaining three wheels. Several mitigating features have been planned, and some already implemented to assure continued operation of the remaining reaction wheels.
Recently, more discovery announcements were made- 

The Kepler-47 system was announced on August 28. This is another Kepler first– a circumbinary system with more than one transiting planet, one of which is in the habitable zone of its parent binary star system.
41 New Transiting Planets. Two newly submitted studies verify 41 new transiting planets in 20 star systems. These results may increase the number of Kepler’s confirmed planets by more than 50 percent to nearly 120 planets hosted in nearly 70 systems, over half of which contain more than one planet. The papers are currently under scientific peer-review.

August 04, 2912 

Kepler Mission Manager Update 08.01.2012
The Kepler team completed another monthly science data download over July 29-30, 2012. This marked the completion of Quarter 13 month 2 of science data collection.

This particular month was interrupted by the pointing error anomaly that Kepler experienced from July 14, 2012 through July 19, 2012. The apparent cause of the anomaly was failure of reaction wheel #2 of the spacecraft’s reaction wheel assembly. Recovery actions included configuring the spacecraft to operate on three reaction wheels. Meanwhile, engineers have continued to evaluate spacecraft telemetry to aid in root cause analysis for the reaction wheel #2 anomaly. Further analysis will determine what additional actions are needed to mitigate against a similar anomaly on the spacecraft's remaining reaction wheels.

On July 28, 2012, the Kepler team released to the public the science data collected during Quarter 7 through Quarter 9. The spacecraft collected these data from Sept. 23, 2010 to June 27, 2011. The public archive is available at the Mikulski Archive for Space Telescopes

The new data release includes data taken in Quarter 8. This was an operationally challenging quarter, as the spacecraft exhibited a new behavior that resulted in a safe mode event and an extended interruption in data collection at the beginning of the quarter. Mitigation of the new behavior -- excess noise on the perceived sun vector -- resulted in another science loss at the end of the quarter. Quarter 8 represents the winter season for the spacecraft, where it is looking over the sun, with relatively small margins against pointing errors. The mitigations against the excess noise proved to be effective this year, when the Quarter 12 winter season was executed without incident.

Interesting results continue to flow from the bounty of data. Recently, the following paper of note was published:
Sanchis-Ojeda et al, 2012 – Researchers have detected the first exoplanet system with regularly aligned orbits similar to those in our solar system. At the center of this system is Kepler-30, a star as bright and massive as the sun. By monitoring stellar spin using star spots, scientists determined the star rotates around a vertical axis and its three planets have orbits that are all in the same plane. This is the first confirmed system with an orientation very similar to our own solar system. The findings are described in a new study published Wednesday, July 25, in the journal Nature.

Finally, also on July 28, 2012, the Kepler team received the Vision to Reality Award from the Space Frontier Foundation. William Borucki, Kepler mission principal investigator, accepted the award on behalf of the team at the New Space 2012 Gala held in Santa Clara, Calif. This award is bestowed for outstanding achievement in the development and operation of a device, system or entity that helps open the space frontier. Kepler is in distinguished company, as previous winners include NanoRacks, Masten Space Systems, and SpaceX..

Roger Hunter

June 25, 2012

Astronomers Discover Planetary Odd Couple

Planetrise: Astronomers have discovered a pair of neighboring planets with dissimilar densities orbiting very close to each other. The planets are too close to their star to be in the so-called "habitable zone," the region in a system where liquid water might exist on the surface, but they have the closest-spaced orbits ever confirmed. The findings are published today in the journal Science. 

May 25, 2012

Kepler Mission Manager Update

April was a momentous time for the mission! The team received approval for a mission extension through fiscal year 2016, based on a recommendation from NASA’s 2012 Senior Review of Astrophysics Missions. In addition to Kepler, eight other missions were approved. The 2012 NASA Senior Review report is available here.

The extended mission will begin in October 2012. The team has been busy preparing a transition plan to carry the mission through 2016. The extended mission paradigm will be to operate with more dependence on, and service to, the astronomical community. The Kepler exoplanet survey will continue, but, to reduce mission cost, the project will support follow-up observation and analysis only of planet candidates near Earth-size and then produce a reliable catalog of the near Earth-size candidates. In addition to continuing the exoplanet survey, the level of Kepler resources devoted to astrophysical studies will be substantially increased to allow much greater community participation in Kepler science. All Kepler survey data will be available to the community for analysis with no proprietary period.

Extended mission planning and implementation are progressing. Methods and infrastructure to facilitate working groups of community scientists to participate both in the survey operation and analysis of survey results are being developed. The Kepler Guest Observer Office is preparing to support observations proposed by the community, as well as access to archival data. Extended mission follow-up observing plans and procedures will be completed in time for trial use in the summer 2012 observing season, before the first season of the extended mission in early 2013. All other preparations for extended mission operation will be in place and functioning by the beginning of October 2012. On April 16, during the opening ceremony of the 28th National Space Symposium, the team was awarded the 2012 John L. "Jack" Swigert, Jr., Award for Space Exploration. We are honored and humbled by this prestigious award AND the remarkable video the team at the Space Foundation produced. Results continue to flow from the data. Recently, two papers of note were published: P. Muirhead et al, 2012 – The finding reports new stellar parameters of 84 cooler late-K and M-type stars reported in the Kepler Input Catalog. Applying the new stellar radii obtained through specialized analysis using the 200-inch Hale Telescope at the Palomar Observatory, the research team's re-evaluation has rendered three super Earth-size planet candidates in the habitable zone. J. Steffen et al, 2012 – In a sample study of 63 hot Jupiter systems, planetary systems with Jupiter-size planet candidates in three day orbits, researchers found no evidence of small, companion candidates. The finding suggests that small candidates were ejected from the system, leaving large planets to later circularize into tight orbits. Meanwhile, routine spacecraft operations continued as the operations team recently downlinked the latest month of science data (the first month of Quarter 13) without issue. The operation occurred April 30, 2012, with about 17 hours interruption in science data collection. As noted in last month’s update, the team continues to monitor increased solar activity as our sun is exhibiting an increase in solar flares and coronal mass ejections (CME). Kepler now has experienced three significant CME events, starting on Day-of-Year (DOY) 23, 27, and 67. The third event was by far the largest; a very small fourth event was observed on DOY 73. The team is pleased to report the spacecraft did not experience any major anomaly. However, the CMEs did impact the quality of the science data collected during the events. The three significant events produced noticeable changes in dark current, discernible pointing excursions, and significant flux variations for all target stars. As a result, the team has chosen to disregard the data collected during these CMEs. This has resulted in data losses of roughly 2.2, 1.0, and 4.6 days, respectively, during the three events. Their long-term impact on the spacecraft and its detectors is still under investigation, but appears to be small and non-threatening to overall mission success. Our Science Operations Center (SOC) ground system software team continues its busy pace. The SOC 8.1 software release, deployed in March 2012, continues as the baseline pipeline software system, while the team has been focused on readying the SOC 8.2 software release for operations. As noted previously, SOC 8.2 adds features to: (a) improve corrections of the systematic errors in stellar flux time series; (b) improves sensitivity to planetary systems with two transits only; and (c) improves sensitivity to small planets in multiple planet systems. We expect to deploy this capability in late June 2012. Finally, the Kepler team marked the third anniversary since beginning science operations. On May 12, 2009, we completed the final commissioning activities for the Kepler spacecraft and entered operations. The three years have gone by quickly, and the mission has produced many exciting discoveries. With a mission extension of four years recently granted, we expect that Kepler’s best days - and discoveries, - lie ahead.


Kepler Planet Candidates by Size, Feb. 27, 2012

The histogram summarizes the findings in the Feb. 27, 2012 Kepler Planet Candidate catalog release. The catalog contains 2,321 planet candidates identified during the first 16 months of observation conducted May 2009 to September 2010. Of the 46 planet candidates found in the habitable zone, the region in the planetary system where liquid water could exist, ten of these candidates are near-Earth-size.

Kepler Mission Manager Update

Since the last update, the team has participated in some major events in the last 30 days. On Feb. 29, 2012, a Kepler project team contingent briefed a senior review panel and NASA Headquarters members on a proposal for extending the Kepler baseline mission. Satellite operations are scheduled to conclude in November 2012. The extended mission briefing proposed an additional two years of science data collection with an option for another two years beyond that. On March 7, the Kepler mission team received the 2012 Aviation Week Laureate Award for Space at a formal dinner in Washington DC. This is a significant honor, and the team is humbled by the selection for such a prestigious award. 

Kepler at 2,326 Planet Canidates (see image below) 

NASA's Kepler Announces 11 Planetary Systems Hosting 26 Planets 01.26.12

NASA's Kepler mission has discovered 11 new planetary systems hosting 26 confirmed planets. These discoveries nearly double the number of verified Kepler planets and triple the number of stars known to have more than one planet that transits, or passes in front of, its host star. Such systems will help astronomers better understand how planets form.

The planets orbit close to their host stars and range in size from 1.5 times the radius of Earth to larger than Jupiter. Fifteen of them are between Earth and Neptune in size, and further observations will be required to determine which are rocky like Earth and which have thick gaseous atmospheres like Neptune. The planets orbit their host star once every six to 143 days. All are closer to their host star than Venus is to our sun. 

Jan. 11, 2012

Trent J. Perrotto
Headquarters, Washington

Michele Johnson
Ames Research Center, Moffett Field, Calif.

Whitney Clavin
Jet Propulsion Laboratory, Pasadena, Calif.

RELEASE: 12-013


WASHINGTON -- Astronomers using data from NASA's Kepler mission have
discovered the three smallest planets yet detected orbiting a star
beyond our sun. The planets orbit a single star, called KOI-961, and
are 0.78, 0.73 and 0.57 times the radius of Earth. The smallest is
about the size of Mars.

All three planets are thought to be rocky like Earth, but orbit close
to their star. That makes them too hot to be in the habitable zone,
which is the region where liquid water could exist. Of the more than
700 planets confirmed to orbit other stars -- called exoplanets --
only a handful are known to be rocky.

"Astronomers are just beginning to confirm thousands of planet
candidates uncovered by Kepler so far," said Doug Hudgins, Kepler
program scientist at NASA Headquarters in Washington. "Finding one as
small as Mars is amazing, and hints that there may be a bounty of
rocky planets all around us."

Kepler searches for planets by continuously monitoring more than
150,000 stars, looking for telltale dips in their brightness caused
by crossing, or transiting, planets. At least three transits are
required to verify a signal as a planet. Follow-up observations from
ground-based telescopes also are needed to confirm the discoveries.

The latest discovery comes from a team led by astronomers at the
California Institute of Technology in Pasadena. The team used data
publicly released by the Kepler mission, along with follow-up
observations from the Palomar Observatory, near San Diego, and the
W.M. Keck Observatory atop Mauna Kea in Hawaii. Their measurements
dramatically revised the sizes of the planets from what originally
was estimated.

The three planets are very close to their star, taking less than two
days to orbit around it. The KOI-961 star is a red dwarf with a
diameter one-sixth that of our sun, making it just 70 percent bigger
than Jupiter.

"This is the tiniest solar system found so far," said John Johnson,
the principal investigator of the research from NASA's Exoplanet
Science Institute at the California Institute of Technology in
Pasadena. "It's actually more similar to Jupiter and its moons in
scale than any other planetary system. The discovery is further proof
of the diversity of planetary systems in our galaxy."

Red dwarfs are the most common kind of star in our Milky Way galaxy.
The discovery of three rocky planets around one red dwarf suggests
that the galaxy could be teeming with similar rocky planets.

"These types of systems could be ubiquitous in the universe," said
Phil Muirhead, lead author of the new study from Caltech. "This is a
really exciting time for planet hunters."

The discovery follows a string of recent milestones for the Kepler
mission. In December 2011, scientists announced the mission's first
confirmed planet in the habitable zone of a sun-like star: a planet
2.4 times the size of Earth called Kepler-22b. Later in the month,
the team announced the discovery of the first Earth-size planets
orbiting a sun-like star outside our solar system, called Kepler-20e
and Kepler-20f.

For the latest discovery, the team obtained the sizes of the three
planets called KOI-961.01, KOI-961.02 and KOI-961.03 with the help of
a well-studied twin star to KOI-961, or Barnard's Star. By better
understanding the KOI-961 star, they then could determine how big the
planets must be to have caused the observed dips in starlight. In
addition to the Kepler observations and ground-based telescope
measurements, the team used modeling techniques to confirm the planet

Prior to these confirmed planets, only six other planets had been
confirmed using the Kepler public data.

NASA's Ames Research Center in Moffett Field, Calif., manages Kepler's
ground system development, mission operations and science data
analysis. NASA's Jet Propulsion Laboratory, Pasadena, Calif., managed
the Kepler mission's development.

For information about the Kepler Mission, visit: 


NASA Discovers First Earth-size Planets Beyond Our Solar System

MOFFET FIELD, Calif. -- NASA's Kepler mission has discovered the first Earth-size planets orbiting a sun-like star outside our solar system. The planets, called Kepler-20e and Kepler-20f, are too close to their star to be in the so-called habitable zone where liquid water could exist on a planet's surface, but they are the smallest exoplanets ever confirmed around a star like our sun.

The discovery marks the next important milestone in the ultimate search for planets like Earth. The new planets are thought to be rocky. Kepler-20e is slightly smaller than Venus, measuring 0.87 times the radius of Earth. Kepler-20f is a bit larger than Earth, measuring 1.03 times its radius. Both planets reside in a five-planet system called Kepler-20, approximately 1,000 light-years away in the constellation Lyra.

NASA Kepler Reaching into the Stars:
We are entering a golden era for "stellar physics" – a term coined to describe research about the formation, evolution, interior and the atmospheres of stars. Thanks to a partnership forged among stellar astrophysics, scientists and NASA’s Kepler Mission, a goldmine of data is now available to support the world's efforts to detect planets in the habitable zone around other stars.
Kepler Scientific Objectives:
The scientific objective of the Kepler Mission is to explore the structure and diversity of planetary systems. This is achieved by surveying a large sample of stars to:
Determine the percentage of terrestrial and larger planets that are in or near the habitable zone of a wide variety of stars.
Determine the distribution of sizes and shapes of the orbits of these planets.
Estimate how many planets there are in multiple-star systems.
Determine the variety of orbit sizes and planet reflectivities, sizes, masses and densities of short-period giant planets.
Identify additional members of each discovered planetary system using other techniques Determine the properties of those stars that harbor planetary systems. 
The Kepler project team has recovered spacecraft from its Safe Mode event that occurred on Feb. 1, 2011. The spacecraft returned to science data collection after an outage of 64 hours. The likely cause was corrupt star tracker data that resulted in a false momentum alarm on the spacecraft. Fault protection software reacted properly in making the spacecraft safe until the project engineers could contact the spacecraft and review telemetry. An anomaly response team will continue to evaluate the telemetry to understand the root cause of the corrupt star tracker data and develop further mitigations.

While conducting recovery of the spacecraft from the Safe Mode event, the project downloaded science data from the spacecraft's solid state recorder that was collected since Jan. 6. That data is now being routed to the Kepler Science Operations Center where it will be processed for the science team's evaluation. The team is making plans for the next science data collection download and spacecraft quarterly roll.
Feb. 02, 2011

Trent Perrotto
Headquarters, Washington

Michael Mewhinney/Rachel Hoover
Ames Research Center, Moffett Field, Calif.

RELEASE: 11-030


WASHINGTON -- NASA's Kepler mission has discovered its first
Earth-size planet candidates and its first candidates in the
habitable zone, a region where liquid water could exist on a planet's
surface. Five of the potential planets are near Earth-size and orbit
in the habitable zone of smaller, cooler stars than our sun.

Candidates require follow-up observations to verify they are actual
planets. Kepler also found six confirmed planets orbiting a sun-like
star, Kepler-11. This is the largest group of transiting planets
orbiting a single star yet discovered outside our solar system.

"In one generation we have gone from extraterrestrial planets being a
mainstay of science fiction, to the present, where Kepler has helped
turn science fiction into today's reality," said NASA Administrator
Charles Bolden. "These discoveries underscore the importance of
NASA's science missions, which consistently increase understanding of
our place in the cosmos."

The discoveries are part of several hundred new planet candidates
identified in new Kepler mission science data, released on Tuesday,
Feb. 1. The findings increase the number of planet candidates
identified by Kepler to-date to 1,235. Of these, 68 are approximately
Earth-size; 288 are super-Earth-size; 662 are Neptune-size; 165 are
the size of Jupiter and 19 are larger than Jupiter.

Of the 54 new planet candidates found in the habitable zone, five are
near Earth-sized. The remaining 49 habitable zone candidates range
from super-Earth size -- up to twice the size of Earth -- to larger
than Jupiter.

The findings are based on the results of observations conducted May 12
to Sept. 17, 2009, of more than 156,000 stars in Kepler's field of
view, which covers approximately 1/400 of the sky.

"The fact that we've found so many planet candidates in such a tiny
fraction of the sky suggests there are countless planets orbiting
sun-like stars in our galaxy," said William Borucki of NASA's Ames
Research Center in Moffett Field, Calif., the mission's science
principal investigator. "We went from zero to 68 Earth-sized planet
candidates and zero to 54 candidates in the habitable zone, some of
which could have moons with liquid water."

Among the stars with planetary candidates, 170 show evidence of
multiple planetary candidates. Kepler-11, located approximately 2,000
light years from Earth, is the most tightly packed planetary system
yet discovered. All six of its confirmed planets have orbits smaller
than Venus, and five of the six have orbits smaller than Mercury's.
The only other star with more than one confirmed transiting planet is
Kepler-9, which has three. The Kepler-11 findings will be published
in the Feb. 3 issue of the journal Nature.

"Kepler-11 is a remarkable system whose architecture and dynamics
provide clues about its formation," said Jack Lissauer, a planetary
scientist and Kepler science team member at Ames. "These six planets
are mixtures of rock and gases, possibly including water. The rocky
material accounts for most of the planets' mass, while the gas takes
up most of their volume. By measuring the sizes and masses of the
five inner planets, we determined they are among the lowest mass
confirmed planets beyond our solar system."

All of the planets orbiting Kepler-11 are larger than Earth, with the
largest ones being comparable in size to Uranus and Neptune. The
innermost planet, Kepler-11b, is ten times closer to its star than
Earth is to the sun. Moving outward, the other planets are
Kepler-11c, Kepler-11d, Kepler-11e, Kepler-11f, and the outermost
planet, Kepler-11g, which is half as far from its star as Earth is
from the sun.

The planets Kepler-11d, Kepler-11e and Kepler-11f have a significant
amount of light gas, which indicates that they formed within a few
million years of the system's formation.

"The historic milestones Kepler makes with each new discovery will
determine the course of every exoplanet mission to follow," said
Douglas Hudgins, Kepler program scientist at NASA Headquarters in

Kepler, a space telescope, looks for planet signatures by measuring
tiny decreases in the brightness of stars caused by planets crossing
in front of them. This is known as a transit.

Since transits of planets in the habitable zone of sun-like stars
occur about once a year and require three transits for verification,
it is expected to take three years to locate and verify Earth-size
planets orbiting sun-like stars.

The Kepler science team uses ground-based telescopes and the
Space Telescope
to review observations on planetary candidates and
other objects of interest the spacecraft finds.

The star field that Kepler observes in the constellations Cygnus and
Lyra can only be seen from ground-based observatories in spring
through early fall. The data from these other observations help
determine which candidates can be validated as planets.

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Kepler: The Search for Earth-Size Planets Begins
Since its launch in March, 2009, the Kepler Mission has announced the discovery of 9 confirmed exoplanets (or planets outside our solar system). Data from ground-based observatories and precise asteroseismic analysis to determine if Earths are common or rare in our Galaxy. NASA's Kepler mission confirmed the discovery of its first rocky planet, named Kepler-10b. Measuring 1.4 times the size of Earth, it is the smallest planet ever discovered outside our solar system.
The discovery of this so-called exoplanet is based on more than eight months of data collected by the spacecraft from May 2009 to early January 2010.
Kepler's First Five Discoveries:
All known 400+ exoplanets as of Dec 2009 plus the 5 new planets found with Kepler. The green band represents the parameters for habitable planets. Too close to the Sun and water vaporizes. Too far from the Sun and water freezes. Too low of a mass, and the planet does not have enough surface gravity to hold onto a life sustaining atmosphere. Too large of a mass and the planet has enough gravity to hold onto the most abundant element in the universe, hydrogen, and become a gas-giant planet.
Kepler Launch and Deployment Complete
Credit: NASA/Kepler mission/Dana Berry