A5040233150- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Nuclear physics research studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Astronomical Observations and Instrumentation
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
- Quantum Chromodynamics and Particle Interactions
- Gamma-ray bursts and supernovae
- Particle physics theoretical and experimental studies
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Chemical Physics Studies
- Nuclear reactor physics and engineering
- Space Exploration and Technology
- Neutrino Physics Research
- High-pressure geophysics and materials
- Astrophysical Phenomena and Observations
- Calibration and Measurement Techniques
- Advanced NMR Techniques and Applications
- Adaptive optics and wavefront sensing
- Atmospheric Ozone and Climate
- Planetary Science and Exploration
- Particle Detector Development and Performance
NASA Exoplanet Science Institute
2018-2025
California Institute of Technology
2017-2024
University of Oxford
1995-2024
The Ohio State University
2024
University of Southern Queensland
2024
University of California, Berkeley
2024
Leibniz Institute for Astrophysics Potsdam
2024
Infrared Processing and Analysis Center
2018-2021
Drexel University
2019-2021
University of York
2011-2020
The size of a planet is an observable property directly connected to the physics its formation and evolution. We used precise radius measurements from California-Kepler Survey (CKS) study distribution 2025 $\textit{Kepler}$ planets in fine detail. detect factor $\geq$2 deficit occurrence rate at 1.5-2.0 R$_{\oplus}$. This gap splits population close-in ($P$ < 100 d) small into two regimes: R$_P$ 1.5 R$_{\oplus}$ = 2.0-3.0 R$_{\oplus}$, with few between. Planets these regimes have nearly same...
Las Cumbres Observatory Global Telescope (LCOGT) is a young organization dedicated to time-domain observations at optical and (potentially) near-IR wavelengths. To this end, LCOGT constructing worldwide network of telescopes, including the two 2 m Faulkes as many 17 × 1 23 40 cm telescopes. These telescopes initially will be outfitted for imaging (excepting telescopes) spectroscopy wavelengths between atmospheric UV cutoff roughly 1-μm limit silicon detectors. Since first LCOGT's are now...
Abstract The distribution of planet sizes encodes details formation and evolution. We present the most precise size to date based on Gaia parallaxes, Kepler photometry, spectroscopic temperatures from California- Survey. Previously, we measured stellar radii 11% precision using high-resolution spectroscopy; by adding astrometry, errors are now 3%. Planet radius measurements are, in turn, improved 5% precision. With a catalog ∼1000 planets with properties, probed fine detail gap that...
Various theoretical models treating the effect of stellar irradiation on planetary envelopes predict presence a radius valley: i.e. bimodal distribution planet radii, with super-Earths and sub-Neptune planets separated by valley at around $\approx 2~R_\oplus$. Such was observed recently, owing to an improvement in precision stellar, therefore radii. Here we investigate presence, location shape such using small sample highly accurate parameters determined from asteroseismology, which includes...
ABSTRACT The primary Kepler Mission provided nearly continuous monitoring of ∼200,000 objects with unprecedented photometric precision. We present the final catalog eclipsing binary systems within 105 deg 2 field view. This release incorporates full extent data from mission (Q0-Q17 Data Release). As a result, new have been added, additional false positives removed, ephemerides and principal parameters recomputed, classifications revised to rely on analytical models, eclipse timing variations...
Probing the connection between a star's metallicity and presence properties of any associated planets offers an observational link conditions during epoch planet formation mature planetary systems. We explore this by analyzing metallicities Kepler target stars subset found to host transiting planets. After correcting for survey incompleteness, we measure occurrence: number per 100 with given $M$. Planet occurrence correlates some, but not all, sizes orbital periods. For warm super-Earths...
In this paper we search for distant massive companions to known transiting gas giant planets that may have influenced the dynamical evolution of these systems. We present new radial velocity observations a sample 51 obtained using Keck HIRES instrument, and find statistically significant accelerations in fifteen Six systems no previously reported published literature: HAT-P-10, HAT-P-22, HAT-P-29, HAT-P-32, WASP-10, XO-2. combine our fits with NIRC2 adaptive optics (AO) imaging data place...
We have established precise planet radii, semimajor axes, incident stellar fluxes, and masses for 909 planets in 355 multi-planet systems discovered by Kepler. In this sample, we find that within a single system correlated sizes: each is more likely to be the size of its neighbor than drawn at random from distribution observed sizes. with three or planets, tend regular spacing: orbital period ratios adjacent pairs are correlated. Furthermore, smaller suggesting patterns sizes spacing linked...
We present the discovery of KELT-1b, first transiting low-mass companion from wide-field Kilodegree Extremely Little Telescope-North (KELT-North) survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star. brown dwarf or super-massive planet with mass 27.23+/-0.50 MJ and radius 1.110+0.037-0.024 RJ, on very short period (P=1.21750007) circular orbit. KELT-1b receives large amount stellar insolation, an equilibrium temperature assuming zero albedo perfect redistribution...
HAT-P-20b is a giant metal-rich exoplanet orbiting star. We analyze two secondary eclipses of the planet in each 3.6 and 4.5 μm bands Warm Spitzer. have developed simple, powerful, radically different method to correct intra-pixel effect for Spitzer data, which we call pixel-level decorrelation (PLD). PLD corrects very effectively, but without explicitly using—or even measuring—the fluctuations apparent position stellar image. illustrate validate using synthetic real data comparing results...
We present a high-precision radial velocity (RV) survey of 719 FGKM stars, which host 164 known exoplanets and 14 newly discovered or revised substellar companions. This catalog updated the orbital parameters long-period candidates, some have decades-longer observational baselines than they did upon initial detection. The range from warm sub-Neptunes super-Earths to cold gas giants. sample selection criteria, as well over 100,000 RV measurements, come Keck-HIRES, APF-Levy, Lick-Hamilton...
Most of our knowledge planets orbiting nearby stars comes from Doppler surveys. For spaced-based, high-contrast imaging missions, with Doppler-discovered are attractive targets. The known orbits tell missions where and when to observe, the dynamically determined masses provide important constraints for interpretation planetary spectra. Quantifying set planet that could have been detected will enable more efficient discovery characterization. We analyzed measurements Lick Keck Observatories...
We present 197 planet candidates discovered using data from the first year of NASA K2 mission (Campaigns 0-4), along with results an intensive program photometric analyses, stellar spectroscopy, high-resolution imaging, and statistical validation. distill these into sets 104 validated planets (57 in multi-planet systems), 30 false positives, 63 remaining candidates. Our systems span a range properties, median values R_P = 2.3 R_E, P=8.6 d, Tef 5300 K, Kp=12.7 mag. Stellar spectroscopy...
We conducted a Doppler survey at Keck combined with NIRC2 K-band AO imaging to search for massive, long-period companions 123 known exoplanet systems one or two planets detected using the radial velocity (RV) method. Our is sensitive Jupiter mass out 20 AU majority of stars in our sample, and we report discovery eight new planets, addition statistically significant RV trends indicating presence an outer companion beyond 5 AU. combine observations determine range allowed masses orbital...
Abstract We used high-precision radial velocity measurements of FGKM stars to determine the occurrence giant planets as a function orbital separation spanning 0.03–30 au. Giant are more prevalent at distances 1–10 au compared orbits interior or exterior this range. The increase in planet ∼1 by factor ∼4 is highly statistically significant. A fall-off larger favored over models with flat increasing occurrence. measure <?CDATA ${14.1}_{-1.8}^{+2.0}$?> <mml:math...
We use radial velocity observations to search for long-period gas giant companions in systems hosting inner super-Earth (1-4 R_Earth, 1-10 M_Earth) planets constrain formation and migration scenarios this population. consistently re-fit published RV datasets 65 stars find 9 with statistically significant trends indicating the presence of an outer companion. combine these data AO images masses semi-major axes companions. quantify our sensitivity by fitting sample a power law distribution...
Abstract In 2017, the California-Kepler Survey (CKS) published its first data release (DR1) of high-resolution optical spectra 1305 planet hosts. Refined CKS radii revealed that small planets are bifurcated into two distinct populations, super-Earths (smaller than 1.5 R ⊕ ) and sub-Neptunes (between 2.0 4.0 ), with few in between (the “radius gap”). Several theoretical models radius gap predict variation stellar mass, but testing these predictions is challenging DR1 due to limited M ⋆ range...
On May 31, 2011 UT a supernova (SN) exploded in the nearby galaxy M51 (the Whirlpool Galaxy). We discovered this event using small telescopes equipped with CCD cameras, as well by Palomar Transient Factory (PTF) survey, and rapidly confirmed it to be Type II supernova. Our early light curve spectroscopy indicates that PTF11eon resulted from explosion of relatively compact progenitor star evidenced rapid shock-breakout cooling seen curve, low temperature early-time spectra prompt appearance...
Small, cool planets represent the typical end-products of planetary formation. Studying architectures these systems, measuring planet masses and radii, observing planets' atmospheres during transit directly informs theories assembly, migration, evolution. Here we report discovery three small orbiting a bright (Ks = 8.6 mag) M0 dwarf using data collected as part K2, new ecliptic survey re-purposed Kepler spacecraft. Stellar spectroscopy K2 photometry indicate that system hosts transiting with...
We analyze full-orbit phase curve observations of the transiting hot Jupiters WASP-19b and HAT-P-7b at 3.6 4.5 $\mu$m obtained using Spitzer Space Telescope. For WASP-19b, we measure secondary eclipse depths $0.485\%\pm 0.024\%$ $0.584\%\pm 0.029\%$ $\mu$m, which are consistent with a single blackbody effective temperature $2372 \pm 60$ K. The measured for $0.156\%\pm 0.009\%$ $0.190\%\pm 0.006\%$, well-described by $2667\pm 57$ Comparing curves to predictions one-dimensional...