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Thomas Barclay,
Christopher J. Burke,
Steve B. Howell,
Jason F. Rowe,
Daniel Huber,
Howard Isaacson,
Jon M. Jenkins,
Rea Kolbl,
Geoffrey W. Marcy,
Elisa V. Quintana, [......],
Michael R. Haas,
Roger Hunter,
Jack J. Lissauer,
Fergal Mullally,
Anima Sabale, Shawn E. Seader,
Jeffrey C. Smith,
Peter Tenenbaum,
AKM Kamal Uddin,
Susan E. Thompson
[show abstract]
[hide abstract]
ABSTRACT: We present the discovery of a super-earth-sized planet in or near the
habitable zone of a sun-like star. The host is Kepler-69, a 13.7 mag G4V-type
star. We detect two periodic sets of transit signals in the three-year flux
time series of Kepler-69, obtained with the Kepler spacecraft. Using the very
high precision Kepler photometry, and follow-up observations, our confidence
that these signals represent planetary transits is >99.1%. The inner planet,
Kepler-69b, has a radius of 2.24+/-0.4 Rearth and orbits the host star every
13.7 days. The outer planet, Kepler-69c, is a super-Earth-size object with a
radius of 1.7+/-0.3 Rearth and an orbital period of 242.5 days. Assuming an
Earth-like Bond albedo, Kepler-69c has an equilibrium temperature of 299 +/- 19
K, which places the planet close to the habitable zone around the host star.
This is the smallest planet found by Kepler to be orbiting in or near habitable
zone of a Sun-like star and represents an important step on the path to finding
the first true Earth analog.
04/2013;
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Roberto Sanchis-Ojeda,
Daniel C Fabrycky,
Joshua N Winn,
Thomas Barclay,
Bruce D Clarke,
Eric B Ford,
Jonathan J Fortney,
John C Geary,
Matthew J Holman,
Andrew W Howard,
Jon M Jenkins,
David Koch,
Jack J Lissauer,
Geoffrey W Marcy,
Fergal Mullally,
Darin Ragozzine, Shawn E Seader,
Martin Still,
Susan E Thompson
[show abstract]
[hide abstract]
ABSTRACT: The Sun's equator and the planets' orbital planes are nearly aligned, which is presumably a consequence of their formation from a single spinning gaseous disk. For exoplanetary systems this well-aligned configuration is not guaranteed: dynamical interactions may tilt planetary orbits, or stars may be misaligned with the protoplanetary disk through chaotic accretion , magnetic interactions or torques from neighbouring stars. Indeed, isolated 'hot Jupiters' are often misaligned and even orbiting retrograde. Here we report an analysis of transits of planets over starspots on the Sun-like star Kepler-30 (ref. 8), and show that the orbits of its three planets are aligned with the stellar equator. Furthermore, the orbits are aligned with one another to within a few degrees. This configuration is similar to that of our Solar System, and contrasts with the isolated hot Jupiters. The orderly alignment seen in the Kepler-30 system suggests that high obliquities are confined to systems that experienced disruptive dynamical interactions. Should this be corroborated by observations of other coplanar multi-planet systems, then star-disk misalignments would be ruled out as the explanation for the high obliquities of hot Jupiters, and dynamical interactions would be implicated as the origin of hot Jupiters.
Nature 07/2012; 487(7408):449-53. · 36.28 Impact Factor
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Natalie M. Batalha,
Jason F. Rowe,
Stephen T. Bryson,
Thomas Barclay,
Christopher J. Burke,
Douglas A. Caldwell,
Jessie L. Christiansen,
Fergal Mullally,
Susan E. Thompson,
Timothy M. Brown, [......],
Martin Still,
Martin C. Stumpe,
Jill C. Tarter,
Peter Tenenbaum,
Guillermo Torres,
Joseph D. Twicken,
Kamal Uddin,
Jeffrey Van Cleve,
Lucianne Walkowicz,
William F. Welsh
[show abstract]
[hide abstract]
ABSTRACT: New transiting planet candidates are identified in sixteen months (May 2009 -
September 2010) of data from the Kepler spacecraft. Nearly five thousand
periodic transit-like signals are vetted against astrophysical and instrumental
false positives yielding 1,091 viable new planet candidates, bringing the total
count up to over 2,300. Improved vetting metrics are employed, contributing to
higher catalog reliability. Most notable is the noise-weighted robust averaging
of multi-quarter photo-center offsets derived from difference image analysis
which identifies likely background eclipsing binaries. Twenty-two months of
photometry are used for the purpose of characterizing each of the new
candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are
tabulated as well as the products of light curve modeling: reduced radius
(Rp/R*), reduced semi-major axis (d/R*), and impact parameter (b). The largest
fractional increases are seen for the smallest planet candidates (197% for
candidates smaller than 2Re compared to 52% for candidates larger than 2Re) and
those at longer orbital periods (123% for candidates outside of 50-day orbits
versus 85% for candidates inside of 50-day orbits). The gains are larger than
expected from increasing the observing window from thirteen months (Quarter 1--
Quarter 5) to sixteen months (Quarter 1 -- Quarter 6). This demonstrates the
benefit of continued development of pipeline analysis software. The fraction of
all host stars with multiple candidates has grown from 17% to 20%, and the
paucity of short-period giant planets in multiple systems is still evident. The
progression toward smaller planets at longer orbital periods with each new
catalog release suggests that Earth-size planets in the Habitable Zone are
forthcoming if, indeed, such planets are abundant.
02/2012;
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Jack J. Lissauer,
Geoffrey W. Marcy,
Jason F. Rowe,
Stephen T. Bryson,
Elisabeth Adams,
Lars A. Buchhave,
David R. Ciardi,
William D. Cochran,
Daniel C. Fabrycky,
Eric B. Ford, [......],
Steve B. Howell,
Jon M. Jenkins,
Karen Kinemuchi,
David G. Koch,
Robert C. Morehead,
Darin Ragozzine, Shawn E. Seader,
Peter G. Tanenbaum,
Guillermo Torres,
Joseph D. Twicken
[show abstract]
[hide abstract]
ABSTRACT: We present a statistical analysis that demonstrates that the overwhelming
majority of Kepler candidate multiple transiting systems (multis) indeed
represent true, physically-associated transiting planets. Binary stars provide
the primary source of false positives among Kepler planet candidates, implying
that false positives should be nearly randomly-distributed among Kepler
targets. In contrast, true transiting planets would appear clustered around a
smaller number of Kepler targets if detectable planets tend to come in systems
and/or if the orbital planes of planets encircling the same star are
correlated. There are more than one hundred times as many Kepler planet
candidates in multi-candidate systems as would be predicted from a random
distribution of candidates, implying that the vast majority are true planets.
Most of these multis are multiple planet systems orbiting the Kepler target
star, but there are likely cases where (a) the planetary system orbits a
fainter star, and the planets are thus significantly larger than has been
estimated, or (b) the planets orbit different stars within a binary/multiple
star system. We use the low overall false positive rate among Kepler multis,
together with analysis of Kepler spacecraft and ground-based data, to validate
the closely-packed Kepler-33 planetary system, which orbits a star that has
evolved somewhat off of the main sequence. Kepler-33 hosts five transiting
planets with periods ranging from 5.67 to 41 days.
01/2012;
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Francois Fressin,
Guillermo Torres,
Jason F Rowe,
David Charbonneau,
Leslie A Rogers,
Sarah Ballard,
Natalie M Batalha,
William J Borucki,
Stephen T Bryson,
Lars A Buchhave, [......],
Darin Ragozzine,
Dimitar D Sasselov,
Sara Seager,
Thomas Barclay,
Fergal Mullally, Shawn E Seader,
Martin Still,
Joseph D Twicken,
Susan E Thompson,
Kamal Uddin
[show abstract]
[hide abstract]
ABSTRACT: Since the discovery of the first extrasolar giant planets around Sun-like stars, evolving observational capabilities have brought us closer to the detection of true Earth analogues. The size of an exoplanet can be determined when it periodically passes in front of (transits) its parent star, causing a decrease in starlight proportional to its radius. The smallest exoplanet hitherto discovered has a radius 1.42 times that of the Earth's radius (R(⊕)), and hence has 2.9 times its volume. Here we report the discovery of two planets, one Earth-sized (1.03R(⊕)) and the other smaller than the Earth (0.87R(⊕)), orbiting the star Kepler-20, which is already known to host three other, larger, transiting planets. The gravitational pull of the new planets on the parent star is too small to measure with current instrumentation. We apply a statistical method to show that the likelihood of the planetary interpretation of the transit signals is more than three orders of magnitude larger than that of the alternative hypothesis that the signals result from an eclipsing binary star. Theoretical considerations imply that these planets are rocky, with a composition of iron and silicate. The outer planet could have developed a thick water vapour atmosphere.
Nature 12/2011; 482(7384):195-8. · 36.28 Impact Factor
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Francois Fressin,
Guillermo Torres,
Jason F. Rowe,
David Charbonneau,
Leslie A. Rogers,
Sarah Ballard,
Natalie M. Batalha,
William J. Borucki,
Stephen T. Bryson,
Lars A. Buchhave, [......],
Darin Ragozzine,
Dimitar D. Sasselov,
Sara Seager,
Thomas Barclay,
Fergal Mullally, Shawn E. Seader,
Martin Still,
Joseph D. Twicken,
Susan E. Thompson,
Kamal Uddin
[show abstract]
[hide abstract]
ABSTRACT: Since the discovery of the first extrasolar giant planets around Sun-like
stars, evolving observational capabilities have brought us closer to the
detection of true Earth analogues. The size of an exoplanet can be determined
when it periodically passes in front of (transits) its parent star, causing a
decrease in starlight proportional to its radius. The smallest exoplanet
hitherto discovered has a radius 1.42 times that of the Earth's radius (R
Earth), and hence has 2.9 times its volume. Here we report the discovery of two
planets, one Earth-sized (1.03R Earth) and the other smaller than the Earth
(0.87R Earth), orbiting the star Kepler-20, which is already known to host
three other, larger, transiting planets. The gravitational pull of the new
planets on the parent star is too small to measure with current
instrumentation. We apply a statistical method to show that the likelihood of
the planetary interpretation of the transit signals is more than three orders
of magnitude larger than that of the alternative hypothesis that the signals
result from an eclipsing binary star. Theoretical considerations imply that
these planets are rocky, with a composition of iron and silicate. The outer
planet could have developed a thick water vapour atmosphere.
12/2011;
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[show abstract]
[hide abstract]
ABSTRACT: We use the KOI-13 transiting star-planet system as a test case for the recently developed BEER algorithm, aimed at identifying non-transiting low-mass companions by detecting the photometric variability induced by the companion along its orbit. Such photometric variability is generated by three mechanisms: the beaming effect, tidal ellipsoidal distortion, and reflection/heating. We use data from three Kepler quarters, from the first year of the mission, while ignoring measurements within the transit and occultation, and show that the planet's ephemeris is clearly detected. We fit for the amplitude of each of the three effects and use the beaming effect amplitude to estimate the planet's minimum mass, which results in Mp sin i = 9.2 ± 1.1 M J (assuming the host star parameters derived by Szabo et al.). Our results show that non-transiting star-planet systems similar to KOI-13.01 can be detected in Kepler data, including a measurement of the orbital ephemeris and the planet's minimum mass. Moreover, we derive a realistic estimate of the amplitudes uncertainties, and use it to show that data obtained during the entire lifetime of the Kepler mission of 3.5 years will allow detecting non-transiting close-in low-mass companions orbiting bright stars, down to the few Jupiter mass level. Data from the Kepler Extended Mission, if funded by NASA, will further improve the detection capabilities.
The Astronomical Journal 11/2011; 142(6):195. · 4.03 Impact Factor
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Michael Endl,
Phillip J. MacQueen,
William D. Cochran,
Erik J. Brugamyer,
Lars A. Buchhave,
Jason Rowe,
Phillip Lucas,
Howard Isaacson,
Steve Bryson,
Steve B. Howell, [......],
David J. Koch,
Jack J. Lissauer,
Pavel Machalek,
Martin Still,
William F. Welsh,
Dwight T. Sanderfer, Shawn E. Seader,
Jeffrey C. Smith,
Susan E. Thompson,
and Joseph D. Twicken
[show abstract]
[hide abstract]
ABSTRACT: We report the discovery of Kepler-15b (KOI-128), a new transiting exoplanet detected by NASA's Kepler mission. The transit signal with a period of 4.94 days was detected in the quarter 1 (Q1) Kepler photometry. For the first time, we have used the High Resolution Spectrograph (HRS) at the Hobby-Eberly Telescope (HET) to determine the mass of a Kepler planet via precise radial velocity (RV) measurements. The 24 HET/HRS RVs and 6 additional measurements from the Fibre-fed Échelle Spectrograph spectrograph at the Nordic Optical Telescope reveal a Doppler signal with the same period and phase as the transit ephemeris. We used one HET/HRS spectrum of Kepler-15 taken without the iodine cell to determine accurate stellar parameters. The host star is a metal-rich ([Fe/H] = 0.36 ± 0.07) G-type main-sequence star with T eff = 5515 ± 124 K. The semi-amplitude K of the RV orbit is 78.7+8.5 –9.5 m s–1, which yields a planet mass of 0.66 ± 0.1 M Jup. The planet has a radius of 0.96 ± 0.06 R Jup and a mean bulk density of 0.9 ± 0.2 g cm–3. The radius of Kepler-15b is smaller than the majority of transiting planets with similar mass and irradiation level. This suggests that the planet is more enriched in heavy elements than most other transiting giant planets. For Kepler-15b we estimate a heavy element mass of 30-40 M ⊕.
The Astrophysical Journal Supplement Series 11/2011; 197(1):13. · 13.46 Impact Factor
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Timothy R. White,
Timothy R. Bedding,
Dennis Stello,
Thierry Appourchaux,
Jérôme Ballot,
Othman Benomar,
Alfio Bonanno,
Anne-Marie Broomhall,
Tiago L. Campante,
William J. Chaplin, [......],
Benoit Mosser,
Mario J. P. F. G. Monteiro,
Clara Régulo,
David Salabert,
Victor Silva Aguirre,
Michael J. Thompson,
Graham Verner,
Robert L. Morris,
Dwight T. Sanderfer, Shawn E. Seader
[show abstract]
[hide abstract]
ABSTRACT: Photometric observations made by the NASA Kepler Mission have led to a dramatic increase in the number of main-sequence and subgiant stars with detected solar-like oscillations. We present an ensemble asteroseismic analysis of 76 solar-type stars. Using frequencies determined from the Kepler time-series photometry, we have measured three asteroseismic parameters that characterize the oscillations: the large frequency separation (\Delta \nu), the small frequency separation between modes of l=0 and l=2 (\delta \nu_02), and the dimensionless offset (\epsilon). These measurements allow us to construct asteroseismic diagrams, namely the so-called C-D diagram of \delta \nu_02 versus \Delta \nu, and the recently re-introduced {\epsilon} diagram. We compare the Kepler results with previously observed solar-type stars and with theoretical models. The positions of stars in these diagrams places constraints on their masses and ages. Additionally, we confirm the observational relationship between {\epsilon} and T_eff that allows for the unambiguous determination of radial order and should help resolve the problem of mode identification in F stars.
The Astrophysical Journal Letters 10/2011; 742:L3. · 5.53 Impact Factor
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Michael Endl,
Phillip J. MacQueen,
William D. Cochran,
Erik Brugamyer,
Lars A. Buchhave,
Jason Rowe,
Phillip Lucas,
Howard Issacson,
Steve Bryson,
Steve B. Howell, [......],
David J. Koch,
Jack J. Lissauer,
Pavel Machalek,
Martin Still,
William F. Welsh,
Dwight T. Sanderfer, Shawn E. Seader,
Jeffrey C. Smith,
Susan E. Thompson,
Joseph D. Twicken
[show abstract]
[hide abstract]
ABSTRACT: We report the discovery of Kepler-15b, a new transiting exoplanet detected by
NASA's Kepler mission. The transit signal with a period of 4.94 days was
detected in the quarter 1 (Q1) Kepler photometry. For the first time, we have
used the High-Resolution-Spectrograph (HRS) at the Hobby-Eberly Telescope (HET)
to determine the mass of a Kepler planet via precise radial velocity (RV)
measurements. The 24 HET/HRS radial velocities (RV) and 6 additional
measurements from the FIES spectrograph at the Nordic Optical Telescope (NOT)
reveal a Doppler signal with the same period and phase as the transit
ephemeris. We used one HET/HRS spectrum of Kepler-15 taken without the iodine
cell to determine accurate stellar parameters. The host star is a metal-rich
([Fe/H]=0.36+/-0.07) G-type main sequence star with T_eff=5515+/-124 K. The
amplitude of the RV-orbit yields a mass of the planet of 0.66+/-0.1 M_Jup. The
planet has a radius of 0.96+/-0.06 R_Jup and a mean bulk density of 0.9+/-0.2
g/cm^3. The planetary radius resides on the lower envelope for transiting
planets with similar mass and irradiation level. This suggests significant
enrichment of the planet with heavy elements. We estimate a heavy element mass
of 30-40 M_Earth within Kepler-15b.
07/2011;
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Robert W. Slawson,
Andrej Prsa,
William F. Welsh,
Jerome A. Orosz,
Michael Rucker,
Natalie M. Batalha,
Laurance R. Doyle,
Scott G. Engle,
Kyle Conroy,
Jared Coughlin, [......],
Daniel C. Fabrycky,
Steve B. Howell,
Jon M. Jenkins,
Kamal Uddin,
Fergal Mullally, Shawn E. Seader,
Susan E. Thompson,
Dwight T. Sanderfer,
William Borucki,
David Koch
[show abstract]
[hide abstract]
ABSTRACT: The Kepler Mission provides nearly continuous monitoring of ~156 000 objects
with unprecedented photometric precision. Coincident with the first data
release, we presented a catalog of 1879 eclipsing binary systems identified
within the 115 square degree Kepler FOV. Here, we provide an updated catalog
augmented with the second Kepler data release which increases the baseline
nearly 4-fold to 125 days. 386 new systems have been added, ephemerides and
principle parameters have been recomputed. We have removed 42 previously
cataloged systems that are now clearly recognized as short-period pulsating
variables and another 58 blended systems where we have determined that the
Kepler target object is not itself the eclipsing binary. A number of
interesting objects are identified. We present several exemplary cases: 4 EBs
that exhibit extra (tertiary) eclipse events; and 8 systems that show clear
eclipse timing variations indicative of the presence of additional bodies bound
in the system. We have updated the period and galactic latitude distribution
diagrams. With these changes, the total number of identified eclipsing binary
systems in the Kepler field-of-view has increased to 2165, 1.4% of the Kepler
target stars.
03/2011;
