Search Publications
HIP 33609 b: An Eccentric Brown Dwarf Transiting a V = 7.3 Rapidly Rotating B Star
Kostov, Veselin B.; Torres, Guillermo; Vanderburg, Andrew +42 more
We present the discovery and characterization of HIP 33609 b, a transiting warm brown dwarf orbiting a late B star, discovered by NASA's Transiting Exoplanet Survey Satellite as TOI-588 b. HIP 33609 b is a large (R b = ${1.580}_{-0.070}^{+0.074}$ R J) brown dwarf on a highly eccentric (e = ${0.560}_{-0.031}^{+0.029}$ ) orbit …
Visual Orbits and Alignments of Planet-hosting Binary Systems
Lester, Kathryn V.; Littlefield, Colin; Howell, Steve B. +7 more
Roughly half of Solar-type planet hosts have stellar companions, so understanding how these binary companions affect the formation and evolution of planets is an important component to understanding planetary systems overall. Measuring the dynamical properties of planet host binaries enables a valuable test of planet formation in multistar systems…
An Investigation of Open Clusters Berkeley 68 and Stock 20 Using CCD UBV and Gaia DR3 Data
Yontan, Talar
We performed detailed photometric and astrometric analyses of the open star clusters Berkeley 68 and Stock 20. This was based on ground-based CCD UBV photometric data complemented by space-based Gaia Data Release 3 (DR3) photometry and astrometry. A total of 198 and 51 stars were identified as likely cluster members for Berkeley 68 and Stock 20, r…
An In-depth Look at TOI-3884b: A Super-Neptune Transiting an M4Dwarf with Persistent Starspot Crossings
Kobulnicky, Henry A.; Kowalski, Adam F.; Cochran, William D. +25 more
We perform an in-depth analysis of the recently validated TOI-3884 system, an M4-dwarf star with a transiting super-Neptune. Using high-precision light curves obtained with the 3.5 m Apache Point Observatory and radial velocity observations with the Habitable-zone Planet Finder, we derive a planetary mass of ${32.6}_{-7.4}^{+7.3}\,{M}_{\oplus }$ a…
Estimating Distances from Parallaxes. VI. A Method for Inferring Distances and Transverse Velocities from Parallaxes and Proper Motions Demonstrated on Gaia Data Release 3
Bailer-Jones, C. A. L.
The accuracy of stellar distances inferred purely from parallaxes degrades rapidly with distance. Proper motion measurements, when combined with some idea of typical velocities, provide independent information on stellar distances. Here, I build a direction- and distance-dependent model of the distribution of stellar velocities in the Galaxy, then…
The MUSCLES Extension for Atmospheric Transmission Spectroscopy: UV and X-Ray Host-star Observations for JWST ERS & GTO Targets
Brown, Alexander; France, Kevin; Youngblood, Allison +8 more
X-ray through infrared spectral energy distributions (SEDs) are essential for understanding a star's effect on exoplanet atmospheric composition and evolution. We present a catalog of panchromatic SEDs, hosted on the Barbara A. Mikulski Archive for Space Telescopes, for 11 exoplanet-hosting stars that have guaranteed JWST observation time as part …
The Eclipsing Binaries from the LAMOST Medium-resolution Survey. III. A High-precision Empirical Stellar Mass Library
Li, Jiadong; Xiong, Jianping; Liu, Chao +6 more
High-precision stellar masses and radii measured directly from binaries can effectively calibrate stellar models. However, such a database containing full spectral types and a large range of metallicity is still not fully established. A continuous effort of data collection and analysis is requested to complete the database. In this work, we provid…
Measurement of the Angular Momenta of Pre-main-sequence Stars: Early Evolution of Slow and Fast Rotators and Empirical Constraints on Spin-down Torque Mechanisms
Stassun, Keivan G.; Kounkel, Marina; Hillenbrand, Lynne A. +3 more
We use TESS full-frame imaging data to investigate the angular momentum evolution of young stars in the Orion Complex. We confirm recent findings that stars with rotation periods faster than 2 days are overwhelmingly binaries, with typical separations of tens of au; such binaries quickly clear their disks, leading to a tendency for rapid rotators …
Automatic Classification of Galaxy Morphology: A Rotationally-invariant Supervised Machine-learning Method Based on the Unsupervised Machine-learning Data Set
Lin, Zesen; Kong, Xu; Gu, Yizhou +8 more
Classification of galaxy morphology is a challenging but meaningful task for the enormous amount of data produced by the next-generation telescope. By introducing the adaptive polar-coordinate transformation, we develop a rotationally-invariant supervised machine-learning (SML) method that ensures consistent classifications when rotating galaxy im…
JWST's PEARLS: Dust Attenuation and Gravitational Lensing in the Backlit-galaxy System VV 191
Grogin, Norman A.; Hathi, Nimish P.; Koekemoer, Anton M. +28 more
We derive the spatial and wavelength behavior of dust attenuation in the multiple-armed spiral galaxy VV 191b using backlighting by the superimposed elliptical system VV 191a in a pair with an exceptionally favorable geometry for this measurement. Imaging using the James Webb Space Telescope and Hubble Space Telescope spans the wavelength range 0.…