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Elisa V. Quintana,
Jason F. Rowe,
Thomas Barclay,
Steve B. Howell,
David R. Ciardi,
Brice-Olivier Demory,
Douglas A. Caldwell,
William J. Borucki,
Jessie L. Christiansen,
Jon M. Jenkins,
Todd C. Klaus,
Benjamin J. Fulton,
Robert L. Morris, Dwight T. Sanderfer,
Avi Shporer,
Jeffrey C. Smith,
Martin Still,
Susan E. Thompson
[show abstract]
[hide abstract]
ABSTRACT: We present high precision photometry of Kepler-41, a giant planet in a 1.86
day orbit around a G6V star that was recently confirmed through radial velocity
measurements. We have developed a new method to confirm giant planets solely
from the photometric light curve, and we apply this method herein to Kepler-41
to establish the validity of this technique. We generate a full phase
photometric model by including the primary and secondary transits, ellipsoidal
variations, Doppler beaming and reflected/emitted light from the planet. Third
light contamination scenarios that can mimic a planetary transit signal are
simulated by injecting a full range of dilution values into the model, and we
re-fit each diluted light curve model to the light curve. The resulting
constraints on the maximum occultation depth and stellar density combined with
stellar evolution models rules out stellar blends and provides a measurement of
the planet's mass, size, and temperature. We expect about two dozen Kepler
giant planets can be confirmed via this method.
03/2013;
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Peter Tenenbaum,
Jessie L. Christiansen,
Jon M. Jenkins,
Jason F. Rowe,
Shawn Seader,
Douglas A. Caldwell,
Bruce D. Clarke,
Jie Li,
Elisa V. Quintana,
Jeffrey C. Smith, [......],
Miles T. Cote,
Michael R. Haas, Dwight T. Sanderfer,
Forrest R. Girouard,
Todd C. Klaus,
Christopher K. Middour,
Bill Wohler,
Natalie M. Batalha,
Thomas Barclay,
and James E. Nickerson
[show abstract]
[hide abstract]
ABSTRACT: We present the results of a search for potential transit signals in the first three quarters of photometry data acquired by the Kepler mission. The targets of the search include 151,722 stars which were observed over the full interval and an additional 19,132 stars which were observed for only one or two quarters. From this set of targets we find a total of 5392 detections which meet the Kepler detection criteria: those criteria are periodicity of signal, an acceptable signal-to-noise ratio, and a composition test which rejects spurious detections which contain non-physical combinations of events. The detected signals are dominated by events with relatively low signal-to-noise ratio and by events with relatively short periods. The distribution of estimated transit depths appears to peak in the range between 40 and 100 parts per million, with a few detections down to fewer than 10 parts per million. The detections exhibit signal-to-noise ratios from 7.1σ, which is the lower cutoff for detections, to over 10,000σ, and periods ranging from 0.5 days, which is the lower cutoff used in the procedure, to 109 days, which is the upper limit of achievable periods given the length of the data set and the criteria used for detections. The detected signals are compared to a set of known transit events in the Kepler field of view which were derived by a different method using a longer data interval; the comparison shows that the current search correctly identified 88.1% of the known events. A tabulation of the detected transit signals, examples which illustrate the analysis and detection process, a discussion of future plans and open, potentially fruitful, areas of further research are included.
The Astrophysical Journal Supplement Series 02/2012; 199(1):24. · 13.46 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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Jason H. Steffen,
Eric B. Ford,
Jason F. Rowe,
Daniel C. Fabrycky,
Matthew J. Holman,
William F. Welsh,
William J. Borucki,
Natalie M. Batalha,
Steve Bryson,
Douglas A. Caldwell,
David R. Ciardi,
Jon M. Jenkins,
Hans Kjeldsen,
David G. Koch,
Andrej Prsa, Dwight T. Sanderfer,
Shawn Seader,
Joseph D. Twicken
[show abstract]
[hide abstract]
ABSTRACT: We analyze the deviations of transit times from a linear ephemeris for the
Kepler Objects of Interest (KOI) through Quarter six (Q6) of science data. We
conduct two statistical tests for all KOIs and a related statistical test for
all pairs of KOIs in multi-transiting systems. These tests identify several
systems which show potentially interesting transit timing variations (TTVs).
Strong TTV systems have been valuable for the confirmation of planets and their
mass measurements. Many of the systems identified in this study should prove
fruitful for detailed TTV studies.
01/2012;
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Thomas N. Gautier III,
David Charbonneau,
Jason F. Rowe,
Geoffrey W. Marcy,
Howard Isaacson,
Guillermo Torres,
Francois Fressin,
Leslie A. Rogers,
Jean-Michel Désert,
Lars A. Buchhave, [......],
Jack J. Lissauer, Dwight T. Sanderfer,
Dimitar D. Sasselov,
Sara Seager,
Kathryn Silverio,
Jeffrey C. Smith,
Martin Still,
Martin C. Stumpe,
Peter Tenenbaum,
Jeffrey Van Cleve
[show abstract]
[hide abstract]
ABSTRACT: We present the discovery of the Kepler-20 planetary system, which we
initially identified through the detection of five distinct periodic transit
signals in the Kepler light curve of the host star 2MASSJ19104752+4220194. We
find a stellar effective temperature Teff=5455+-100K, a metallicity of
[Fe/H]=0.01+-0.04, and a surface gravity of log(g)=4.4+-0.1. Combined with an
estimate of the stellar density from the transit light curves we deduce a
stellar mass of Mstar=0.912+-0.034 Msun and a stellar radius of
Rstar=0.944^{+0.060}_{-0.095} Rsun. For three of the transit signals, our
results strongly disfavor the possibility that these result from astrophysical
false positives. We conclude that the planetary scenario is more likely than
that of an astrophysical false positive by a factor of 2e5 (Kepler-20b), 1e5
(Kepler-20c), and 1.1e3 (Kepler-20d), sufficient to validate these objects as
planetary companions. For Kepler-20c and Kepler-20d, the blend scenario is
independently disfavored by the achromaticity of the transit: From Spitzer data
gathered at 4.5um, we infer a ratio of the planetary to stellar radii of
0.075+-0.015 (Kepler-20c) and 0.065+-0.011 (Kepler-20d), consistent with each
of the depths measured in the Kepler optical bandpass. We determine the orbital
periods and physical radii of the three confirmed planets to be 3.70d and
1.91^{+0.12}_{-0.21} Rearth for Kepler-20b, 10.85 d and 3.07^{+0.20}_{-0.31}
Rearth for Kepelr-20c, and 77.61 d and 2.75^{+0.17}_{-0.30} Rearth for
Kepler-20d. From multi-epoch radial velocities, we determine the masses of
Kepler-20b and Kepler-20c to be 8.7\+-2.2 Mearth and 16.1+-3.5 Mearth,
respectively, and we place an upper limit on the mass of Kepler-20d of 20.1
Mearth (2 sigma).
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;
