Results for "Lars A. Buchhave"

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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
Transits and Occultations of an Earth-Sized Planet in an 8.5-Hour OrbitMay 17 2013Jul 13 2013We report the discovery of an Earth-sized planet ($1.16\pm 0.19 R_\oplus$) in an 8.5-hour orbit around a late G-type star (KIC 8435766, Kepler-78). The object was identified in a search for short-period planets in the {\it Kepler} database and confirmed ... 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
HST/COS Detection of the Spectrum of the Subdwarf Companion of KOI-81May 04 2015KOI-81 is a totally eclipsing binary discovered by the Kepler mission that consists of a rapidly rotating B-type star and a small, hot companion. The system was forged through large scale mass transfer that stripped the mass donor of its envelope and ... More
A Transiting Jupiter AnalogFeb 29 2016Decadal-long radial velocity surveys have recently started to discover analogs to the most influential planet of our solar system, Jupiter. Detecting and characterizing these worlds is expected to shape our understanding of our uniqueness in the cosmos. ... 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
The Mass of the White Dwarf Companion in the Self-Lensing Binary KOI-3278: Einstein vs. NewtonApr 24 2019Jun 04 2019KOI-3278 is a self-lensing stellar binary consisting of a white-dwarf secondary orbiting a Sun-like primary star. Kruse and Agol (2014) noticed small periodic brightenings every 88.18 days in the Kepler photometry and interpreted these as the result of ... 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
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
Asteroseismology of the Hyades with K2: first detection of main-sequence solar-like oscillations in an open clusterAug 25 2016The Hyades open cluster was targeted during Campaign 4 (C4) of the NASA K2 mission, and short-cadence data were collected on a number of cool main-sequence stars. Here, we report results on two F-type stars that show detectable oscillations of a quality ... 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
Validation of small Kepler transiting planet candidates in or near the habitable zoneNov 03 2017A main goal of NASA's Kepler Mission is to establish the frequency of potentially habitable Earth-size planets (eta Earth). Relatively few such candidates identified by the mission can be confirmed to be rocky via dynamical measurement of their mass. ... 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
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
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 Curious Case of KOI 4: Confirming Kepler's First ExoplanetMar 04 2019The discovery of thousands of planetary systems by Kepler has demonstrated that planets are ubiquitous. However, a major challenge has been the confirmation of Kepler planet candidates, many of which still await confirmation. One of the most enigmatic ... 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
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
The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planetMay 30 2014Kepler-10b was the first rocky planet detected by the Kepler satellite and con- firmed with radial velocity follow-up observations from Keck-HIRES. The mass of the planet was measured with a precision of around 30%, which was insufficient to constrain ... 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
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
Discovery and Validation of Kepler-452b: A 1.6-Re Super Earth Exoplanet in the Habitable Zone of a G2 StarJul 24 2015We report on the discovery and validation of Kepler-452b, a transiting planet identified by a search through the 4 years of data collected by NASA's Kepler Mission. This possibly rocky 1.63$^{+0.23}_{-0.20}$ R$_\oplus$ planet orbits its G2 host star every ... 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
The role of binaries in the enrichment of the early Galactic halo. I. r-process-enhanced metal-poor starsSep 17 2015The detailed chemical composition of most metal-poor halo stars has been found to be highly uniform, but a minority of stars exhibit dramatic enhancements in their abundances of heavy neutron-capture elements and/or of carbon. The key question for Galactic ... More
Almost All of Kepler's Multiple Planet Candidates are PlanetsJan 26 2012We 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 ... More
HAT-P-65b and HAT-P-66b: Two Transiting Inflated Hot Jupiters and Observational Evidence for the Re-Inflation of Close-In Giant PlanetsSep 09 2016We present the discovery of the transiting exoplanets HAT-P-65b and HAT-P-66b, with orbital periods of 2.6055 d and 2.9721 d, masses of $0.527 \pm 0.083$ M$_{J}$ and $0.783 \pm 0.057$ M$_{J}$ and inflated radii of $1.89 \pm 0.13$ R$_{J}$ and $1.59^{+0.16}_{-0.10}$ ... 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
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
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
Inferring Explosion Properties from Type II-Plateau Supernova Light CurvesMar 21 2019We present advances in modeling Type IIP supernovae using \texttt{MESA} for evolution to shock breakout coupled with \texttt{STELLA} for generating light and radial velocity curves. Explosion models and synthetic light curves can be used to translate ... 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
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
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
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 hot-Jupiter Kepler-17b: discovery, obliquity from stroboscopic starspots, and atmospheric characterizationJul 28 2011Oct 26 2011This paper reports the discovery and characterization of the transiting hot giant exoplanet Kepler-17b. The planet has an orbital period of 1.486 days, and radial velocity measurements from the Hobby-Eberly Telescope (HET) show a Doppler signal of 420+/-15 ... 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
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 role of binaries in the enrichment of the early Galactic halo. II. Carbon-Enhanced Metal-Poor Stars - CEMP-no starsNov 25 2015The detailed composition of most metal-poor halo stars has been found to be very uniform. However, a fraction of 20-70% (increasing with decreasing metallicity) exhibit dramatic enhancements in their abundances of carbon - the so-called carbon-enhanced ... 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
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
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
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
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
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
Kepler-68: Three Planets, One With a Density Between That of Earth and Ice GiantsFeb 11 2013NASA's Kepler Mission has revealed two transiting planets orbiting Kepler-68. Follow-up Doppler measurements have established the mass of the innermost planet and revealed a third jovian-mass planet orbiting beyond the two transiting planets. Kepler-68b, ... More
KompicsTesting - Unit Testing Event StreamsMay 12 2017In this paper we present KompicsTesting, a framework for unit testing components in the Kompics component model. Components in Kompics are event-driven entities which communicate asynchronously solely by message passing. Similar to actors in the actor ... More
Dynamic triad interactions and evolving turbulence spectraJun 11 2019We investigate the effect of a four-dimensional Fourier transform on the formulation of Navier-Stokes equation in Fourier space and the way the energy is transferred between Fourier components (the so-called triad interactions). We consider the effect ... More
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
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
Asymptotic Performance Analysis of a K-Hop Amplify-and-Forward Relay MIMO ChannelOct 21 2014Mar 09 2016The present paper studies the asymptotic performance of multi-hop amplify-and-forward relay multiple-antenna communication channels. Each multi-antenna terminal in the network amplifies the received signal, sent by a source, and retransmits it upstream ... 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-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 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
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
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
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
KELT-17b: A hot-Jupiter transiting an A-star in a misaligned orbit detected with Doppler tomographyJul 12 2016Sep 02 2016We present the discovery of a hot-Jupiter transiting the V=9.23 mag main-sequence A-star KELT-17 (BD+14 1881). KELT-17b is a 1.31 -0.29/+0.28 Mj, 1.525 -0.060/+0.065 Rj hot-Jupiter in a 3.08 day period orbit misaligned at -115.9 +/- 4.1 deg to the rotation ... More
Two new HATNet hot Jupiters around A stars, and the first glimpse at the occurrence rate of hot Jupiters from TESSJun 02 2019Wide field surveys for transiting planets are well suited to searching diverse stellar populations, enabling a better understanding of the link between the properties of planets and their parent stars. We report the discovery of HAT-P-69 b (TOI 625.01) ... 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
An overview of the gravitational spin Hall effectApr 22 2019In General Relativity, the propagation of electromagnetic waves is usually described by the vacuum Maxwell's equations on a fixed curved background. In the limit of infinitely high frequencies, electromagnetic waves can be localized as point particles, ... 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
Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing VariationsJan 25 2012We present a method to confirm the planetary nature of objects in systems with multiple transiting exoplanet candidates. This method involves a Fourier-Domain analysis of the deviations in the transit times from a constant period that result from dynamical ... 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
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-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
A sub-Mercury-sized exoplanetMay 24 2013Since the discovery of the first exoplanet we have known that other planetary systems can look quite unlike our own. However, until recently we have only been able to probe the upper range of the planet size distribution. The high precision of the Kepler ... 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'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
The Kepler-454 System: A Small, Not-rocky Inner Planet, a Jovian World, and a Distant CompanionNov 29 2015Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like starthat hosts a transiting planet candidate in a 10.6 d orbit. From spectroscopy, we estimate the stellar temperature to be 5687 +/- 50 K, its metallicity to be [m/H] = 0.32 +/- 0.08, ... More
Jupiter Analogues Orbit Stars with an Average Metallicity Close to that of the SunFeb 19 2018Jupiter played an important role in determining the structure and configuration of the Solar System. Whereas hot-Jupiter type exoplanets preferentially form around metal-rich stars, the conditions required for the formation of planets with masses, orbits ... More
The Hunt for Exomoons with Kepler (HEK): III. The First Search for an Exomoon around a Habitable-Zone PlanetJun 06 2013Sep 09 2013Kepler-22b is the first transiting planet to have been detected in the habitable-zone of its host star. At 2.4 Earth radii, Kepler-22b is too large to be considered an Earth-analog, but should the planet host a moon large enough to maintain an atmosphere, ... More
Geometric Analysis and General RelativityDec 23 2005This article discusses methods of geometric analysis in general relativity, with special focus on the role of "critical surfaces" such as minimal surfaces, marginal surface, maximal surfaces and null surfaces.
Maximal supersymmetry and exceptional groupsJun 08 2010The article is a tribute to my old mentor, collaborator and friend Murray Gell-Mann. In it I describe work by Pierre Ramond, Sung-Soo Kim and myself where we describe the N = 8 Supergravity in the light-cone formalism. We show how the Cremmer-Julia E7(7) ... More
Viscosity in a Lepton-Photon UniverseJun 08 2016Jul 27 2016We look at viscosity production in a universe consisting purely of leptons and photons. This is quite close to what the Universe actually look like when the temperature was between $10^{10}$ K and $10^{12}$ K ($1$ -- $100$ MeV). By taking the strong force ... More
The two subset recurrent property of Markov chainsFeb 23 2016This paper proposes a new type of recurrence where we divide the Markov chains into intervals that start when the chain enters into a subset A, then sample another subset B far away from A and end when the chain again return to A. The length of these ... More
The LHCb UpgradeSep 14 2017The LHCb Experiment is preparing a detector upgrade fully exploit the flavour physics potential of the LHC. The whole detector will be read out at the full collision rate and the online event selection will be performed by a software trigger. This will ... More
Skew Hopf algebras, irreducible extensions and the pi-methodJan 15 2007Dec 28 2007To a depth two extension A | B, we associate the dual bialgebroids S := \End {}_BA_B and T := (A \o_B A)^B over the centralizer R=C_A(B). In the set-up where R is a subalgebra of B, which is quite common, two nondegenerate pairings of S and T will define ... More
Fine and coarse multifractal zeta-functions: On the multifractal formalism for multifractal zeta-functionsNov 20 2014Multifractal analysis refers to the study of the local properties of measures and functions, and consists of two parts: the fine multifractal theory and the coarse multifractal theory. The fine and the coarse theory are linked by a web of conjectures ... More
Flicker as a tool for characterizing planets through Asterodensity ProfilingMar 20 2014Variability in the time series brightness of a star on a timescale of 8 hours, known as 'flicker', has been previously demonstrated to serve as a proxy for the surface gravity of a star by Bastien et al. (2013). Although surface gravity is crucial for ... More
Occurrence and core-envelope structure of 1--4x Earth-size planets around Sun-like starsApr 10 2014Small planets, 1-4x the size of Earth, are extremely common around Sun-like stars, and surprisingly so, as they are missing in our solar system. Recent detections have yielded enough information about this class of exoplanets to begin characterizing their ... More
Centralizers and Inverses to Induction as Equivalence of CategoriesApr 30 2005Jun 02 2005Given a ring homomorphism $B \to A$, consider its centralizer $R = A^B$, bimodule endomorphism ring $S = \End {}_BA_B$ and sub-tensor-square ring $T = (A \o_B A)^B$. Nonassociative tensoring by the cyclic modules $R_T$ or ${}_SR$ leads to an equivalence ... More
Algebraic K-theory and trace invariantsApr 21 2003The cyclotomic trace of B\"okstedt-Hsiang-Madsen, the subject of B\"okstedt's lecture at the congress in Kyoto, is a map of pro-abelian groups K_*(A) -> TR_*^.(A;p) from Quillen's algebraic K-theory to a topological refinement of Connes' cyclic homology. ... More
Semisimple Hopf algebras and their depth two Hopf subalgebrasJul 03 2008We prove that a depth two Hopf subalgebra K of a semisimple Hopf algebra H is normal (where the ground field $k$ is algebraically closed of characteristic zero). This means on the one hand that a Hopf subalgebra is normal when inducing (then restricting) ... More
Pseudo-Galois Extensions and Hopf AlgebroidsAug 22 2005Aug 21 2006A pseudo-Galois extension is shown to be a depth two extension. Studying its left bialgebroid, we construct an enveloping Hopf algebroid for the semi-direct product of groups, or more generally involutive Hopf algebras, and their module algebras. It is ... More
Anchor maps and stable modules in depth twoJun 20 2006Aug 14 2006An algebra extension A | B is right depth two if its tensor-square A\otimes_B A is in the Dress category Add A as A-B-bimodules. We consider necessary conditions for right, similarly left, D2 extensions in terms of partial A-invariance of two-sided ideals ... More
Network Rewriting I: The FoundationApr 11 2012A theory is developed which uses "networks" (directed acyclic graphs with some extra structure) as a formalism for expressions in multilinear algebra. It is shown that this formalism is valid for arbitrary PROPs (short for 'PROducts and Permutations category'), ... More
On the structure of nearly pseudo-Kähler manifoldsDec 17 2009Firstly we give a condition to split off the K"ahler factor from a nearly pseudo-K"ahler manifold and apply this to get a structure result in dimension 8. Secondly we extend the construction of nearly K"ahler manifolds from twistor spaces to negatively ... More
Hopf subalgebras and tensor powers of generalized permutation modulesOct 11 2012Jun 12 2014By means of a certain module V and its tensor powers in a finite tensor category, we study a question of whether the depth of a Hopf subalgebra R of a finite-dimensional Hopf algebra H is finite. The module V is the counit representation induced from ... More
Multifractal tubesJul 19 2013Tube formulas refer to the study of volumes of $r$ neighbourhoods of sets. For sets satisfying some (possible very weak) convexity conditions, this has a long history. However, within the past 20 years Lapidus has initiated and pioneered a systematic ... More
Bayesian inference for the stochastic identification of elastoplastic material parameters: Introduction, misconceptions and insightsJun 08 2016Jan 15 2017We discuss Bayesian inference (BI) for the probabilistic identification of material parameters. This contribution aims to shed light on the use of BI for the identification of elastoplastic material parameters. For this purpose a single spring is considered, ... More
An in-Depth Look at Quotient ModulesMay 18 2017Oct 10 2017The coset $G$-space of a finite group and a subgroup is a fundamental module of study of Schur and others around 1930; for example, its endomorphism algebra is a Hecke algebra of double cosets. We study and review its generalization $Q$ to Hopf subalgebras, ... More