skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Kepler-22b: A 2.4 Earth-radius Planet in the Habitable Zone of a Sun-like Star

Journal Article · · Astrophys.J.

A search of the time-series photometry from NASA's Kepler spacecraft reveals a transiting planet candidate orbiting the 11th magnitude G5 dwarf KIC 10593626 with a period of 290 days. The characteristics of the host star are well constrained by high-resolution spectroscopy combined with an asteroseismic analysis of the Kepler photometry, leading to an estimated mass and radius of 0.970 +/- 0.060 MSun and 0.979 +/- 0.020 RSun. The depth of 492 +/- 10ppm for the three observed transits yields a radius of 2.38 +/- 0.13 REarth for the planet. The system passes a battery of tests for false positives, including reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A full BLENDER analysis provides further validation of the planet interpretation by showing that contamination of the target by an eclipsing system would rarely mimic the observed shape of the transits. The final validation of the planet is provided by 16 radial velocities obtained with HIRES on Keck 1 over a one year span. Although the velocities do not lead to a reliable orbit and mass determination, they are able to constrain the mass to a 3{\sigma} upper limit of 124 MEarth, safely in the regime of planetary masses, thus earning the designation Kepler-22b. The radiative equilibrium temperature is 262K for a planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is a rocky planet, it is the first confirmed planet with a measured radius to orbit in the Habitable Zone of any star other than the Sun.

Research Organization:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP)
Contributing Organization:
Kepler
DOE Contract Number:
AC02-07CH11359
OSTI ID:
1962613
Report Number(s):
FERMILAB-PUB-12-899-A; arXiv:1112.1640; oai:inspirehep.net:1080420
Journal Information:
Astrophys.J., Vol. 745
Country of Publication:
United States
Language:
English

References (70)

THE CLIMATE OF HD 189733b FROM FOURTEEN TRANSITS AND ECLIPSES MEASURED BYSPITZER journal September 2010
On detecting terrestrial planets with timing of giant planet transits journal May 2005
The Kepler photometer focal plane array conference July 2008
Chromospheric variations in main-sequence stars journal January 1995
A Search for a Sub-Earth-Sized Companion to GJ 436 and a Novel Method to Calibrate WarmSpitzerIRAC Observations
  • Ballard, Sarah; Charbonneau, David; Deming, Drake
  • Publications of the Astronomical Society of the Pacific, Vol. 122, Issue 897 https://doi.org/10.1086/657159
journal November 2010
THE KEPLER-19 SYSTEM: A TRANSITING 2.2RPLANET AND A SECOND PLANET DETECTED VIA TRANSIT TIMING VARIATIONS journal December 2011
Determination of Stellar Radii from Asteroseismic data journal February 2010
KEPLER 'S FIRST ROCKY PLANET: KEPLER-10b journal February 2011
SELECTION, PRIORITIZATION, AND CHARACTERISTICS OF KEPLER TARGET STARS journal March 2010
PRE-SPECTROSCOPIC FALSE-POSITIVE ELIMINATION OF KEPLER PLANET CANDIDATES journal March 2010
Kepler Planet-Detection Mission: Introduction and First Results journal January 2010
CHARACTERISTICS OF PLANETARY CANDIDATES OBSERVED BY KEPLER . II. ANALYSIS OF THE FIRST FOUR MONTHS OF DATA journal June 2011
KEPLER-4b: A HOT NEPTUNE-LIKE PLANET OF A G0 STAR NEAR MAIN-SEQUENCE TURNOFF journal March 2010
KEPLER INPUT CATALOG: PHOTOMETRIC CALIBRATION AND STELLAR CLASSIFICATION journal September 2011
THE KEPLER PIXEL RESPONSE FUNCTION journal March 2010
HAT-P-16b: A 4 M J PLANET TRANSITING A BRIGHT STAR ON AN ECCENTRIC ORBIT, journal August 2010
INSTRUMENT PERFORMANCE IN KEPLER 's FIRST MONTHS journal March 2010
Detection of Thermal Emission from an Extrasolar Planet journal June 2005
ASTEROSEISMIC INVESTIGATION OF KNOWN PLANET HOSTS IN THE KEPLER FIELD journal March 2010
Gravity and limb-darkening coefficients for the Kepler , CoRoT, Spitzer , uvby , UBVRIJHK , and Sloan photometric systems journal April 2011
KEPLER-18b, c, AND d: A SYSTEM OF THREE PLANETS CONFIRMED BY TRANSIT TIMING VARIATIONS, LIGHT CURVE VALIDATION, WARM-SPITZER PHOTOMETRY, AND RADIAL VELOCITY MEASUREMENTS journal October 2011
Kepler-16: A Transiting Circumbinary Planet journal September 2011
KEPLER-6b: A TRANSITING HOT JUPITER ORBITING A METAL-RICH STAR journal March 2010
The Infrared Array Camera (IRAC) for the Spitzer Space Telescope journal September 2004
Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits journal April 2007
KEPLER-10 c: A 2.2 EARTH RADIUS TRANSITING PLANET IN A MULTIPLE SYSTEM journal October 2011
An In-Depth Study of Grid-Based Asteroseismic Analysis journal March 2011
INITIAL CHARACTERISTICS OF KEPLER SHORT CADENCE DATA journal March 2010
ASTEROSEISMOLOGY OF THE TRANSITING EXOPLANET HOST HD 17156 WITH HUBBLE SPACE TELESCOPE FINE GUIDANCE SENSOR journal December 2010
PHARO: A Near‐Infrared Camera for the Palomar Adaptive Optics System journal January 2001
Kepler-9: A System of Multiple Planets Transiting a Sun-Like Star, Confirmed by Timing Variations journal August 2010
The Octave (Birmingham-Sheffield Hallam) automated pipeline for extracting oscillation parameters of solar-like main-sequence stars journal March 2010
The Use of Transit Timing to Detect Terrestrial-Mass Extrasolar Planets journal February 2005
Observations of Binary Stars with the Differential Speckle Survey Instrument. i. Instrument Description and First Results journal May 2009
SPECKLE CAMERA OBSERVATIONS FOR THE NASA KEPLER MISSION FOLLOW-UP PROGRAM journal June 2011
Automated extraction of oscillation parameters for Kepler observations of solar-type stars journal January 2010
Toward a Deterministic Model of Planetary Formation. III. Mass Distribution of Short‐Period Planets around Stars of Various Masses journal June 2005
DISCOVERY AND ROSSITER-McLAUGHLIN EFFECT OF EXOPLANET KEPLER-8b journal November 2010
OVERVIEW OF THE KEPLER SCIENCE PROCESSING PIPELINE journal March 2010
INITIAL CHARACTERISTICS OF KEPLER LONG CADENCE DATA FOR DETECTING TRANSITING PLANETS journal March 2010
Climate Model Studies of Synchronously Rotating Planets journal June 2003
EXPLORING THE HABITABLE ZONE FOR KEPLER PLANETARY CANDIDATES journal July 2011
Habitable Zones around Main Sequence Stars journal January 1993
The 3.6–8.0 μm Broadband Emission Spectrum of HD 209458b: Evidence for an Atmospheric Temperature Inversion journal January 2008
DISCOVERY OF THE TRANSITING PLANET KEPLER-5b journal March 2010
KEPLER-7b: A TRANSITING PLANET WITH UNUSUALLY LOW DENSITY journal March 2010
A closely packed system of low-mass, low-density planets transiting Kepler-11 journal February 2011
ARCHITECTURE AND DYNAMICS OF KEPLER 'S CANDIDATE MULTIPLE TRANSITING PLANET SYSTEMS journal October 2011
Analytic Light Curves for Planetary Transit Searches journal December 2002
A STELLAR MODEL-FITTING PIPELINE FOR ASTEROSEISMIC DATA FROM THE KEPLER MISSION journal June 2009
ON THE LOW FALSE POSITIVE PROBABILITIES OF KEPLER PLANET CANDIDATES journal August 2011
Rotation, convection, and magnetic activity in lower main-sequence stars journal April 1984
Automatic Determination of Stellar Parameters via Asteroseismology of Stochastically Oscillating Stars: Comparison with Direct Measurements journal December 2010
The Goldilocks Problem: Climatic Evolution and Long-Term Habitability of Terrestrial Planets journal September 1994
A synthetic view on structure and evolution of the Milky Way journal October 2003
Biosignatures from Earth-Like Planets Around M Dwarfs journal December 2005
Habitable planets around the star Gliese 581? journal November 2007
Radius Determination of Solar-Type Stars Using Asteroseismology: what to Expect from the Kepler Mission journal July 2009
A Reappraisal of The Habitability of Planets around M Dwarf Stars journal February 2007
Using color photometry to separate transiting exoplanets from false positives journal September 2004
MODELING KEPLER TRANSIT LIGHT CURVES AS FALSE POSITIVES: REJECTION OF BLEND SCENARIOS FOR KEPLER-9, AND VALIDATION OF KEPLER-9 d, A SUPER-EARTH-SIZE PLANET IN A MULTIPLE SYSTEM journal December 2010
Testing Blend Scenarios for Extrasolar Transiting Planet Candidates. I. OGLE‐TR‐33: A False Positive journal October 2004
Spectroscopic Binaries in a Sample of [ITAL]ROSAT[/ITAL] X-Ray Sources South of the Taurus Molecular Clouds journal March 2002
Palomar adaptive optics project: status and performance conference July 2000
The high-resolution cross-dispersed echelle white-pupil spectrometer of the McDonald Observatory 2.7-m telescope
  • Tull, Robert G.; MacQueen, Phillip J.; Sneden, Christopher
  • Publications of the Astronomical Society of the Pacific, Vol. 107 https://doi.org/10.1086/133548
journal March 1995
Presearch data conditioning in the Kepler Science Operations Center pipeline conference July 2010
Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs journal July 2005
Spectroscopy made easy: A new tool for fitting observations with synthetic spectra journal September 1996
HIRES: the high-resolution echelle spectrometer on the Keck 10-m Telescope
  • Vogt, Steven S.; Allen, Steven L.; Bigelow, Bruce C.
  • 1994 Symposium on Astronomical Telescopes & Instrumentation for the 21st Century, SPIE Proceedings https://doi.org/10.1117/12.176725
conference June 1994
The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO‐3b journal August 2008

Similar Records

Kepler-22b: A 2.4 EARTH-RADIUS PLANET IN THE HABITABLE ZONE OF A SUN-LIKE STAR
Journal Article · Wed Feb 01 00:00:00 EST 2012 · Astrophysical Journal · OSTI ID:1962613

KEPLER's First Rocky Planet: Kepler-10b
Journal Article · Tue Feb 01 00:00:00 EST 2011 · Astrophys.J. · OSTI ID:1962613

MODELING KEPLER TRANSIT LIGHT CURVES AS FALSE POSITIVES: REJECTION OF BLEND SCENARIOS FOR KEPLER-9, AND VALIDATION OF KEPLER-9 d, A SUPER-EARTH-SIZE PLANET IN A MULTIPLE SYSTEM
Journal Article · Thu Jan 20 00:00:00 EST 2011 · Astrophysical Journal · OSTI ID:1962613