Results for "Lars A. Buchhave"

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Pinning down the mass of Kepler-10c: the importance of sampling and model comparisonJul 19 2017Initial RV characterisation of the enigmatic planet Kepler-10c suggested a mass of $\sim17$ M$_\oplus$, which was remarkably high for a planet with radius $2.32$ R$_\oplus$; further observations and subsequent analysis hinted at a (possibly much) lower ... More
The Binary Frequency of r-Process-Element Enhanced Metal-Poor Stars and its Implications: Chemical Tagging in the Primitive Halo of the Milky WayOct 20 2011Oct 25 2011A few rare halo giants in the range [Fe/H] $\simeq -2.9\pm0.3$ exhibit {\it r}-process element abundances that vary as a group by factors up to [$r$/Fe] $\sim80$, relative to those of the iron peak and below. Yet, the astrophysical production site of ... More
Improved spectroscopic parameters for transiting planet hostsAug 06 2012Aug 16 2012We report homogeneous spectroscopic determinations of the effective temperature, metallicity, and projected rotational velocity for the host stars of 56 transiting planets. Our analysis is based primarily on the Stellar Parameter Classification (SPC) ... More
The Possible Moon of Kepler-90g is a False PositiveNov 25 2014The discovery of an exomoon would provide deep insights into planet formation and the habitability of planetary systems, with transiting examples being particularly sought after. Of the hundreds of Kepler planets now discovered, the seven-planet system ... More
Planetary Candidates from the First Year of the K2 MissionNov 24 2015Sep 15 2017The Kepler Space Telescope is currently searching for planets transiting stars along the ecliptic plane as part of its extended K2 mission. We processed the publicly released data from the first year of K2 observations (Campaigns 0, 1, 2, and 3) and searched ... More
The Hunt for Exomoons with Kepler (HEK): V. A Survey of 41 Planetary Candidates for ExomoonsMar 18 2015Sep 24 2015We present a survey of 41 Kepler Objects of Interest (KOIs) for exomoons using Bayesian photodynamics, more than tripling the number of KOIs surveyed with this technique. We find no compelling evidence for exomoons although thirteen KOIs yield spurious ... More
Three regimes of extrasolar planets inferred from host star metallicitiesMay 29 2014Approximately half of the extrasolar planets (exoplanets) with radii less than four Earth radii are in orbits with short periods. Despite their sheer abundance, the compositions of such planets are largely unknown. The available evidence suggests that ... More
Large eccentricity, low mutual inclination: the three-dimensional architecture of a hierarchical system of giant planetsMay 20 2014Jul 12 2014We establish the three-dimensional architecture of the Kepler-419 (previously KOI-1474) system to be eccentric yet with a low mutual inclination. Kepler-419b is a warm Jupiter at semi-major axis a = 0.370 +0.007/-0.006 AU with a large eccentricity e=0.85 ... More
Kepler-424 b: A "Lonely" Hot Jupiter That Found A CompanionSep 29 2014Hot Jupiter systems provide unique observational constraints for migration models in multiple systems and binaries. We report on the discovery of the Kepler-424 (KOI-214) two-planet system, which consists of a transiting hot Jupiter (Kepler-424b) in a ... More
TrES-5: A Massive Jupiter-sized Planet Transiting A Cool G-dwarfAug 17 2011We report the discovery of TrES-5, a massive hot Jupiter that transits the star GSC 03949-00967 every 1.48 days. From spectroscopy of the star we estimate a stellar effective temperature of$5171 +/- 36 K, and from high-precision B, R and I photometry ... More
Qatar Exoplanet Survey : Qatar-3b, Qatar-4b and Qatar-5bJun 22 2016Apr 26 2017We report the discovery of Qatar-3b, Qatar-4b, and Qatar-5b, three new transiting planets identified by the Qatar Exoplanet Survey (QES). The three planets belong to the hot Jupiter family, with orbital periods of $P_{Q3b}$=2.50792 days, $P_{Q4b}$=1.80539 ... More
Asteroseismic properties of solar-type stars observed with the NASA K2 mission: results from Campaigns 1-3 and prospects for future observationsAug 25 2016Sep 13 2016We present an asteroseismic analysis of 33 solar-type stars observed in short cadence during Campaigns (C) 1-3 of the NASA K2 mission. We were able to extract both average seismic parameters and individual mode frequencies for stars with dominant frequencies ... More
Discovery of a Transiting Planet Near the Snow-LineJul 17 2014In most theories of planet formation, the snow-line represents a boundary between the emergence of the interior rocky planets and the exterior ice giants. The wide separation of the snow-line makes the discovery of transiting worlds challenging, yet transits ... More
HAT-P-27b: A hot Jupiter transiting a G star on a 3 day orbitJan 18 2011Mar 24 2011We report the discovery of HAT-P-27b, an exoplanet transiting the moderately bright G8 dwarf star GSC 0333-00351 (V=12.214). The orbital period is 3.039586 +/- 0.000012 d, the reference epoch of transit is 2455186.01879 +/- 0.00054 (BJD), and the transit ... More
Revised Stellar Properties of Kepler Targets for the Q1-17 (DR25) Transit Detection RunSep 14 2016Mar 01 2017The determination of exoplanet properties and occurrence rates using Kepler data critically depends on our knowledge of the fundamental properties (such as temperature, radius and mass) of the observed stars. We present revised stellar properties for ... More
HAT-P-31b,c: A Transiting, Eccentric, Hot Jupiter and a Long-Period, Massive Third-BodyJun 06 2011Jul 07 2011We report the discovery of HAT-P-31b, a transiting exoplanet orbiting the V=11.660 dwarf star GSC 2099-00908. HAT-P-31b is the first HAT planet discovered without any follow-up photometry, demonstrating the feasibility of a new mode of operation for the ... More
The Kepler Cluster Study: Stellar Rotation in NGC6811Apr 14 2011We present rotation periods for 71 single dwarf members of the open cluster NGC6811 determined using photometry from NASA's Kepler Mission. The results are the first from The Kepler Cluster Study which combine Kepler's photometry with ground-based spectroscopy ... More
LSPM J1112+7626: detection of a 41-day M-dwarf eclipsing binary from the MEarth transit surveySep 09 2011We report the detection of eclipses in LSPM J1112+7626, which we find to be a moderately bright (I_C = 12.14 +/- 0.05) very low-mass binary system with an orbital period of 41.03236 +/- 0.00002 days, and component masses M_1 = 0.395 +/- 0.002 Msol and ... More
The Metallicities of Stars With and Without Transiting PlanetsJul 13 2015Host star metallicities have been used to infer observational constraints on planet formation throughout the history of the exoplanet field. The giant planet metallicity correlation has now been widely accepted, but questions remain as to whether the ... More
Kepler-63b: A Giant Planet in a Polar Orbit around a Young Sun-like StarJul 30 2013Aug 26 2013We present the discovery and characterization of a giant planet orbiting the young Sun-like star Kepler-63 (KOI-63, $m_{\rm Kp} = 11.6$, $T_{\rm eff} = 5576$ K, $M_\star = 0.98\, M_\odot$). The planet transits every 9.43 days, with apparent depth variations ... More
KIC 9632895 - The 10th Kepler Transiting Circumbinary PlanetSep 04 2014We present the discovery of KIC 9632895b, a 6.2 Earth-radius planet in a low-eccentricity, 240.5-day orbit about an eclipsing binary. The binary itself consists of a 0.93 and 0.194 solar mass pair of stars with an orbital period of 27.3 days. The plane ... More
The HST PanCET Program: Exospheric Mg II and Fe II in the Near-UV transmission spectrum of WASP-121b using Jitter DecorrelationAug 01 2019We present HST near-ultraviolet (NUV) transits of the hot Jupiter WASP-121b, acquired as part of the PanCET program. Time series spectra during two transit events were used to measure the transmission spectra between 2280 and 3070 Angstroms at a resolution ... More
Kepler-7b: A Transiting Planet with Unusually Low DensityDec 31 2009We report the discovery and confirmation of Kepler-7b, a transiting planet with unusually low density. The mass is less than half that of Jupiter, Mp = 0.43 Mj, but the radius is fifty percent larger, Rp = 1.48 Rj. The resulting density, 0.17 g/cc, is ... More
NLTT 41135: a field M-dwarf + brown dwarf eclipsing binary in a triple system, discovered by the MEarth observatoryJun 09 2010We report the discovery of an eclipsing companion to NLTT 41135, a nearby M5 dwarf that was already known to have a wider, slightly more massive common proper motion companion, NLTT 41136, at 2.4 arcsec separation. Analysis of combined-light and radial ... More
Asteroseismology and Gaia: Testing Scaling Relations Using 2200 Kepler Stars with TGAS ParallaxesMay 12 2017We present a comparison of parallaxes and radii from asteroseismology and Gaia DR1 (TGAS) for 2200 Kepler stars spanning from the main sequence to the red giant branch. We show that previously identified offsets between TGAS parallaxes and distances derived ... More
An approach to Hopf algebras via Frobenius coordinates IIMar 05 2001We study a Hopf algebra $H$, which is finitely generated and projective over a commutative ring $k$, as a $P$-Frobenius algebra. We define modular functions in this setting, and provide a complete proof of Radford's formula for the fourth power of the ... More
The Kepler Follow-up Observation ProgramJan 03 2010The Kepler Mission was launched on March 6, 2009 to perform a photometric survey of more than 100,000 dwarf stars to search for terrestrial-size planets with the transit technique. Follow-up observations of planetary candidates identified by detection ... More
The HST PanCET Program: Hints of Na I & Evidence of a Cloudy Atmosphere for the Inflated Hot Jupiter WASP-52bNov 02 2018We present an optical to near-infrared transmission spectrum of the inflated hot Jupiter WASP-52b using three transit observations from the Space Telescope Imaging Spectrograph (STIS) mounted on the Hubble Space Telescope, combined with Spitzer/Infrared ... More
An Approach to Hopf Algebras via Frobenius Coordinates IMar 01 2001Mar 05 2001In Section 1 we introduce Frobenius coordinates in the general setting that includes Hopf subalgebras. In Sections 2 and 3 we review briefly the theories of Frobenius algebras and augmented Frobenius algebras with some new material in Section 3. In Section ... More
KOI-54: The Kepler Discovery of Tidally-Excited Pulsations and Brightenings in a Highly Eccentric BinaryFeb 08 2011Sep 01 2011Kepler observations of the star HD 187091 (KID 8112039, hereafter KOI-54) revealed a remarkable light curve exhibiting sharp periodic brightening events every 41.8 days with a superimposed set of oscillations forming a beating pattern in phase with the ... More
The Neptune-Sized Circumbinary Planet Kepler-38bAug 18 2012We discuss the discovery and characterization of the circumbinary planet Kepler-38b. The stellar binary is single-lined, with a period of 18.8 days, and consists of a moderately evolved main-sequence star (M_A = 0.949 +/- 0.059 solar masses and R_A = ... More
Qatar-2: A K dwarf orbited by a transiting hot Jupiter and a more massive companion in an outer orbitOct 26 2011We report the discovery and initial characterization of Qatar-2b, a hot Jupiter transiting a V = 13.3 mag K dwarf in a circular orbit with a short period, P_ b = 1.34 days. The mass and radius of Qatar-2b are M_p = 2.49 M_j and R_p = 1.14 R_j, respectively. ... More
A Transiting Hot Jupiter Orbiting a Metal-Rich StarJan 02 2010We announce the discovery of Kepler-6b, a transiting hot Jupiter orbiting a star with unusually high metallicity, [Fe/H] = +0.34 +/- 0.04. The planet's mass is about 2/3 that of Jupiter, Mp = 0.67 Mj, and the radius is thirty percent larger than that ... More
275 Candidates and 149 Validated Planets Orbiting Bright Stars in K2 Campaigns 0-10Feb 14 2018Mar 26 2018Since 2014, NASA's K2 mission has observed large portions of the ecliptic plane in search of transiting planets and has detected hundreds of planet candidates. With observations planned until at least early 2018, K2 will continue to identify more planet ... More
KOI-126: A Triply-Eclipsing Hierarchical Triple with Two Low-Mass StarsFeb 02 2011The Kepler spacecraft has been monitoring the light from 150,000 stars in its primary quest to detect transiting exoplanets. Here we report on the detection of an eclipsing stellar hierarchical triple, identified in the Kepler photometry. KOI-126 (A,(B, ... More
An ultrahot gas-giant exoplanet with a stratosphereAug 03 2017Infrared radiation emitted from a planet contains information about the chemical composition and vertical temperature profile of its atmosphere. If upper layers are cooler than lower layers, molecular gases will produce absorption features in the planetary ... More
Precise Masses in the WASP-47 SystemSep 29 2017We present precise radial velocity observations of WASP-47, a star known to host a hot Jupiter, a distant Jovian companion, and, uniquely, two additional transiting planets in short-period orbits: a super-Earth in a ~19 hour orbit, and a Neptune in a ... More
HAT-P-50b, HAT-P-51b, HAT-P-52b, and HAT-P-53b: Three Transiting Hot Jupiters and a Transiting Hot Saturn From the HATNet SurveyMar 13 2015We report the discovery and characterization of four transiting exoplanets by the HATNet survey. The planet HAT-P-50b has a mass of 1.35 M_J and a radius of 1.29 R_J, and orbits a bright (V = 11.8 mag) M = 1.27 M_sun, R = 1.70 R_sun star every P = 3.1220 ... More
Kepler-432: a red giant interacting with one of its two long period giant planetsNov 17 2014Apr 20 2015We report the discovery of Kepler-432b, a giant planet ($M_b = 5.41^{+0.32}_{-0.18} M_{\rm Jup}, R_b = 1.145^{+0.036}_{-0.039} R_{\rm Jup}$) transiting an evolved star $(M_\star = 1.32^{+0.10}_{-0.07} M_\odot, R_\star = 4.06^{+0.12}_{-0.08} R_\odot)$ ... More
KELT-2Ab: A Hot Jupiter Transiting the Bright (V=8.77) Primary Star of a Binary SystemJun 07 2012Aug 29 2012We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright (V=8.77) primary star of the HD 42176 binary system. The host is a slightly evolved late F-star likely in the very short-lived "blue-hook" stage of evolution, with $\teff=6148\pm48{\rm ... More
An 11 Earth-Mass, Long-Period Sub-Neptune Orbiting a Sun-like StarAug 22 2019Although several thousands of exoplanets have now been detected and characterized, observational biases have led to a paucity of long-period, low-mass exoplanets with measured masses and a corresponding lag in our understanding of such planets. In this ... More
The Mass of Kepler-93b and The Composition of Terrestrial PlanetsDec 30 2014Kepler-93b is a 1.478 +/- 0.019 Earth radius planet with a 4.7 day period around a bright (V=10.2), astroseismically-characterized host star with a mass of 0.911+/-0.033 solar masses and a radius of 0.919+/-0.011 solar radii. Based on 86 radial velocity ... More
Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for Kepler-9, and validation of Kepler-9d, a super-Earth-size planet in a multiple systemAug 25 2010Nov 22 2010Light curves from the Kepler Mission contain valuable information on the nature of the phenomena producing the transit-like signals. To assist in exploring the possibility that they are due to an astrophysical false positive, we describe a procedure (BLENDER) ... More
An optical transmission spectrum for the ultra-hot Jupiter WASP-121b measured with the Hubble Space TelescopeOct 25 2018We present an atmospheric transmission spectrum for the ultra-hot Jupiter WASP-121b, measured using the Space Telescope Imaging Spectrograph (STIS) onboard the Hubble Space Telescope (HST). Across the 0.47-1 micron wavelength range, the data imply an ... More
Tate (co)homology via pinched complexesMay 11 2011Nov 14 2011For complexes of modules we study two new constructions, which we call the pinched tensor product and the pinched Hom. They provide new methods for computing Tate homology and Tate cohomology, which lead to conceptual proofs of balancedness of Tate (co)homology ... More
An extended Perona-Malik model based on probabilistic modelsDec 19 2016The Perona-Malik model has been very successful at restoring images from noisy input. In this paper, we reinterpret the Perona-Malik model in the language of Gaussian scale mixtures and derive some extensions of the model. Specifically, we show that the ... More
A Closely-Packed System of Low-Mass, Low-Density Planets Transiting Kepler-11Feb 01 2011When an extrasolar planet passes in front of its star (transits), its radius can be measured from the decrease in starlight and its orbital period from the time between transits. Multiple planets transiting the same star reveal more: period ratios determine ... More
Discovery and Atmospheric Characterization of Giant Planet Kepler-12b: An Inflated Radius OutlierSep 08 2011We report the discovery of planet Kepler-12b (KOI-20), which at 1.695\pm0.030 RJ is among the handful of planets with super-inflated radii above 1.65 RJ. Orbiting its slightly evolved G0 host with a 4.438-day period, this 0.431\pm0.041 MJ planet is the ... More
Kepler-47: A Transiting Circumbinary Multi-Planet SystemAug 27 2012We report the detection of Kepler-47, a system consisting of two planets orbiting around an eclipsing pair of stars. The inner and outer planets have radii 3.0 and 4.6 times that of the Earth, respectively. The binary star consists of a Sun-like star ... More
KELT-3b: A Hot Jupiter Transiting a V=9.8 Late-F StarNov 05 2012Jun 04 2013We report the discovery of KELT-3b, a moderately inflated transiting hot Jupiter with a mass of 1.477 (-0.067, +0.066) M_J, and radius of 1.345 +/- 0.072 R_J, with an orbital period of 2.7033904 +/- 0.000010 days. The host star, KELT-3, is a V=9.8 late ... More
A quantum subgroup depthOct 04 2016The Green ring of the half quantum group $H=U_n(q)$ is computed in [Chen, Van Oystaeyen, Zhang]. The tensor product formulas between indecomposables may be used for a generalized subgroup depth computation in the setting of quantum groups -- to compute ... More
Vanishing of Tate homology and depth formulas over local ringsJul 15 2011Dec 15 2013Auslander's depth formula for pairs of Tor-independent modules over a regular local ring, depth(M \otimes N) = depth(M) + depth(N) - depth(R), has been generalized in several directions over a span of four decades. In this paper we establish a depth formula ... More
KELT-1b: A Strongly Irradiated, Highly Inflated, Short Period, 27 Jupiter-mass Companion Transiting a mid-F StarJun 07 2012We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star. The companion is a ... More
A First Comparison of Kepler Planet Candidates in Single and Multiple SystemsMar 20 2011In this letter we present an overview of the rich population of systems with multiple candidate transiting planets found in the first four months of Kepler data. The census of multiples includes 115 targets that show 2 candidate planets, 45 with 3, 8 ... More
The Bacterial Chemotactic Response Reflects a Compromise Between Transient and Steady State BehaviorFeb 03 2006Swimming bacteria detect chemical gradients by performing temporal comparisons of recent measurements of chemical concentration. These comparisons are described quantitatively by the chemotactic response function, which we expect to optimize chemotactic ... More
The role of binaries in the enrichment of the early Galactic halo. III. Carbon-enhanced metal-poor stars -- CEMP-s starsJan 13 2016Detailed spectroscopic studies of metal-poor halo stars have highlighted the important role of carbon-enhanced metal-poor (CEMP) stars in understanding the early production and ejection of carbon in the Galaxy and in identifying the progenitors of the ... More
Kepler-21b: A rocky planet around a V = 8.25 magnitude starSep 24 2016HD 179070, aka Kepler-21, is a V = 8.25 F6IV star and the brightest exoplanet host discovered by Kepler. An early detailed analysis by Howell et al. (2012) of the first thirteen months (Q0 - Q5) of Kepler light curves revealed transits of a planetary ... More
K2-291 b: A rocky super-Earth in a 2.2 day orbitJan 14 2019Feb 15 2019K2-291 (EPIC 247418783) is a solar-type star with a radius of R_star = 0.899 $\pm$ 0.034 R_sun and mass of M_star=0.934 $\pm$ 0.038 M_sun. From K2 C13 data, we found one super-Earth planet (R_p = 1.589+0.095-0.072 R_Earth) transiting this star on a short ... More
The First Kepler Mission Planet Confirmed With The Hobby-Eberly Telescope: Kepler-15b, a Hot Jupiter Enriched In Heavy ElementsJul 13 2011We 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 ... More
Characterizing K2 Planet Discoveries: A super-Earth transiting the bright K-dwarf HIP 116454Dec 17 2014We report the first planet discovery from the two-wheeled Kepler (K2) mission: HIP 116454 b. The host star HIP 116454 is a bright (V = 10.1, K = 8.0) K1-dwarf with high proper motion, and a parallax-based distance of 55.2 +/- 5.4 pc. Based on high-resolution ... More
A 1.9 Earth radius rocky planet and the discovery of a non-transiting planet in the Kepler-20 systemAug 24 2016Kepler-20 is a solar-type star (V = 12.5) hosting a compact system of five transiting planets, all packed within the orbital distance of Mercury in our own Solar System. A transition from rocky to gaseous planets with a planetary transition radius of ... More
The Kepler-19 system: a thick-envelope super-Earth with two Neptune-mass companions characterized using Radial Velocities and Transit Timing VariationsMar 20 2017We report a detailed characterization of the Kepler-19 system. This star was previously known to host a transiting planet with a period of 9.29 days, a radius of 2.2 R$_\oplus$ and an upper limit on the mass of 20 M$_\oplus$. The presence of a second, ... More
Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical ModelsJan 25 2012Apr 02 2012Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here ... More
Fundamental Properties of Kepler Planet-Candidate Host Stars using AsteroseismologyFeb 11 2013Mar 26 2013We have used asteroseismology to determine fundamental properties for 66 Kepler planet-candidate host stars, with typical uncertainties of 3% and 7% in radius and mass, respectively. The results include new asteroseismic solutions for four host stars ... More
Stellar Spin-Orbit Misalignment in a Multiplanet SystemOct 16 2013Oct 21 2013Stars hosting hot Jupiters are often observed to have high obliquities, whereas stars with multiple co-planar planets have been seen to have low obliquities. This has been interpreted as evidence that hot-Jupiter formation is linked to dynamical disruption, ... More
Two Earth-sized planets orbiting Kepler-20Dec 20 2011Since 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 ... More
KELT-7b: A hot Jupiter transiting a bright V=8.54 rapidly rotating F-starJan 22 2015May 19 2015We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of $1.28 \pm 0.18$ MJ, radius of $1.53_{-0.047}^{+0.046}$ RJ, and an orbital period of $2.7347749 \pm 0.0000039$ days. The bright host star (HD33643; KELT-7) is an F-star with $V=8.54$, ... More
A Framework for Prioritizing the TESS Planetary Candidates Most Amenable to Atmospheric CharacterizationMay 09 2018Sep 14 2018A key legacy of the recently launched TESS mission will be to provide the astronomical community with many of the best transiting exoplanet targets for atmospheric characterization. However, time is of the essence to take full advantage of this opportunity. ... More
State of the Field: Extreme Precision Radial VelocitiesFeb 25 2016Feb 27 2016The Second Workshop on Extreme Precision Radial Velocities defined circa 2015 the state of the art Doppler precision and identified the critical path challenges for reaching 10 cm/s measurement precision. The presentations and discussion of key issues ... More
Kepler-14b: A massive hot Jupiter transiting an F star in a close visual binaryJun 27 2011We present the discovery of a hot Jupiter transiting an F star in a close visual (0.3" sky projected angular separation) binary system. The dilution of the host star's light by the nearly equal magnitude stellar companion (~ 0.5 magnitudes fainter) significantly ... More
Transit Timing Observations from Kepler: II. Confirmation of Two Multiplanet Systems via a Non-parametric Correlation AnalysisJan 25 2012We present a new method for confirming transiting planets based on the combination of transit timingn variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies are in the same physical system. Orbital stability ... More
Kepler-16: A Transiting Circumbinary PlanetSep 15 2011We report the detection of a planet whose orbit surrounds a pair of low-mass stars. Data from the Kepler spacecraft reveal transits of the planet across both stars, in addition to the mutual eclipses of the stars, giving precise constraints on the absolute ... More
A giant planet undergoing extreme ultraviolet irradiation by its hot massive-star hostJun 21 2017The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extra-solar planets now known, only four giant planets have been found that transit hot, A-type stars ... More
Dynamical compact elastic bodies in general relativityOct 18 2014We prove the local existence of solutions to the Einstein-Elastic equations that represent self-gravitating, relativistic elastic bodies with compact support.
Clustering and dynamic decoupling of dust grains in turbulent molecular cloudsNov 02 2018We present high resolution ($1024^3$) simulations of super-/hyper-sonic isothermal hydrodynamic turbulence inside an interstellar molecular cloud (resolving scales of typically 20 -- 100 AU), including a multi-disperse population of dust grains, i.e., ... More
Water/Icy Super-Earths: Giant Impacts and Maximum Water ContentJul 19 2010Water-rich super-Earth exoplanets are expected to be common. We explore the effect of late giant impacts on the final bulk abundance of water in such planets. We present the results from smoothed particle hydrodynamics simulations of impacts between differentiated ... More
Isotropization of solutions of the Einstein-Vlasov system with Bianchi V symmetryMay 31 2013Jan 03 2014Using the methods developed for different Bianchi class A cosmological models we treat the simplest Bianchi class B model, namely Bianchi type V. The future non-linear stability for solutions of the Einstein-Vlasov system is demonstrated and it is shown ... More
Photon-weighted barycentric correction and its importance for precise radial velocitiesAug 02 2019When applying the barycentric correction to a precise radial velocity measurement, it is common practice to calculate its value only at the photon-weighted midpoint time of the observation instead of integrating over the entire exposure. However, since ... More
KOI-142, the King of Transit Variations, is a Pair of Planets near the 2:1 ResonanceApr 15 2013The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions between planets in a multi-planet system. Many Kepler Objects of Interest (KOIs) exhibit significant TTVs, but KOI-142.01 stands out among them with an unrivaled, ... More
Minimum Radii of Super-Earths: Constraints from Giant ImpactsMar 01 2010The detailed interior structure models of super-Earth planets show that there is degeneracy in the possible bulk compositions of a super-Earth at a given mass and radius, determined via radial velocity and transit measurements, respectively. In addition, ... More
KELT-6b: A P~7.9 d Hot Saturn Transiting a Metal-Poor Star with a Long-Period CompanionAug 10 2013Jan 16 2014We report the discovery of KELT-6b, a mildly-inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of ... More
The Hunt for Exomoons with Kepler (HEK): II. Analysis of Seven Viable Satellite-Hosting Planet CandidatesJan 09 2013Mar 06 2013From the list of 2321 transiting planet candidates announced by the Kepler Mission, we select seven targets with favorable properties for the capacity to dynamically maintain an exomoon and present a detectable signal. These seven candidates were identified ... More
BEER analysis of Kepler and CoRoT light curves: I. Discovery of Kepler-76b: A hot Jupiter with evidence for superrotationApr 25 2013May 10 2013We present the first case in which the BEER algorithm identified a hot Jupiter in the Kepler light curve, and its reality was confirmed by orbital solutions based on follow-up spectroscopy. The companion Kepler-76b was identified by the BEER algorithm, ... More
Misspecified RecoveryNov 28 2014Oct 04 2015Asset prices contain information about the probability distribution of future states and the stochastic discounting of those states as used by investors. To better understand the challenge in distinguishing investors' beliefs from risk-adjusted discounting, ... More
Three's Company: An additional non-transiting super-Earth in the bright HD 3167 system, and masses for all three planetsJun 06 2017HD 3167 is a bright (V = 8.9), nearby K0 star observed by the NASA K2 mission (EPIC 220383386), hosting two small, short-period transiting planets. Here we present the results of a multi-site, multi-instrument radial velocity campaign to characterize ... More
KELT-12b: A $P \sim 5$ Day, Highly Inflated Hot Jupiter Transiting a Mildly Evolved Hot StarAug 16 2016Sep 02 2016We report the discovery of KELT-12b, a highly inflated Jupiter-mass planet transiting a mildly evolved host star. We identified the initial transit signal in the KELT-North survey data and established the planetary nature of the companion through precise ... More
Discovery and Rossiter-McLaughlin Effect of Exoplanet Kepler-8bJan 04 2010We report the discovery and the Rossiter-McLaughlin effect of Kepler-8b, a transiting planet identified by the NASA Kepler Mission. Kepler photometry and Keck-HIRES radial velocities yield the radius and mass of the planet around this F8IV subgiant host ... More
The Detection and Characterization of a Nontransiting Planet by Transit Timing VariationsAug 04 2012The Kepler Mission is monitoring the brightness of ~150,000 stars searching for evidence of planetary transits. As part of the "Hunt for Exomoons with Kepler" (HEK) project, we report a planetary system with two confirmed planets and one candidate planet ... More
The Hunt for Exomoons with Kepler (HEK): IV. A Search for Moons around Eight M-DwarfsJan 06 2014Jan 26 2014With their smaller radii and high cosmic abundance, transiting planets around cool stars hold a unique appeal. As part of our on-going project to measure the occurrence rate of extrasolar moons, we here present results from a survey focussing on eight ... More
The Hunt for Exomoons with Kepler (HEK): I. Description of a New Observational ProjectJan 03 2012Mar 15 2012Two decades ago, empirical evidence concerning the existence and frequency of planets around stars, other than our own, was absent. Since this time, the detection of extrasolar planets from Jupiter-sized to most recently Earth-sized worlds has blossomed ... More
A giant impact as the likely origin of different twins in the Kepler-107 exoplanet systemFeb 04 2019Measures of exoplanet bulk densities indicate that small exoplanets with radius less than 3 Earth radii ($R_\oplus$) range from low-density sub-Neptunes containing volatile elements to higher density rocky planets with Earth-like or iron-rich (Mercury-like) ... More
The Transiting Circumbinary Planets Kepler-34 and Kepler-35Apr 18 2012Most Sun-like stars in the Galaxy reside in gravitationally-bound pairs of stars called "binary stars". While long anticipated, the existence of a "circumbinary planet" orbiting such a pair of normal stars was not definitively established until the discovery ... More
Kepler 18-b, c, and d: A System Of Three Planets Confirmed by Transit Timing Variations, Lightcurve Validation, Spitzer Photometry and Radial Velocity MeasurementsOct 04 2011We report the detection of three transiting planets around a Sunlike star, which we designate Kepler-18. The transit signals were detected in photometric data from the Kepler satellite, and were confirmed to arise from planets using a combination of large ... More
Kepler-36: A Pair of Planets with Neighboring Orbits and Dissimilar DensitiesJun 20 2012In the Solar system the planets' compositions vary with orbital distance, with rocky planets in close orbits and lower-density gas giants in wider orbits. The detection of close-in giant planets around other stars was the first clue that this pattern ... More
Characteristics of planetary candidates observed by Kepler, II: Analysis of the first four months of dataFeb 02 2011Mar 12 2011On 1 February 2011 the Kepler Mission released data for 156,453 stars observed from the beginning of the science observations on 2 May through 16 September 2009. There are 1235 planetary candidates with transit like signatures detected in this period. ... More
The Transiting Exoplanet Survey SatelliteJun 01 2014Oct 28 2014The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical ... More
Kepler-20: A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size CandidatesDec 19 2011Feb 01 2012We 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 ... More
KELT-4Ab: An inflated Hot Jupiter transiting the bright (V~10) component of a hierarchical tripleSep 30 2015We report the discovery of KELT-4Ab, an inflated, transiting Hot Jupiter orbiting the brightest component of a hierarchical triple stellar system. The host star is an F star with $T_{\rm eff}=6206\pm75$ K, $\log g=4.108\pm0.014$, $\left[{\rm Fe}/{\rm ... More
KEPLER's First Rocky Planet: Kepler-10bFeb 03 2011NASA's Kepler Mission uses transit photometry to determine the frequency of earth-size planets in or near the habitable zone of Sun-like stars. The mission reached a milestone toward meeting that goal: the discovery of its first rocky planet, Kepler-10b. ... More
An ultra-short period rocky super-Earth with a secondary eclipse and a Neptune-like companion around K2-141Jan 10 2018Ultra-short period (USP) planets are a class of low mass planets with periods shorter than one day. Their origin is still unknown, with photo-evaporation of mini-Neptunes and in-situ formation being the most credited hypotheses. Formation scenarios differ ... More