Search Publications
Exploring Thousands of Nearby Hierarchical Systems with Gaia and Speckle Interferometry
Tokovinin, Andrei
There should be about 10,000 stellar hierarchical systems within 100 pc with primary stars more massive than 0.5 M ⊙, and a similar amount of less-massive hierarchies. A list of 8000 candidate multiples is derived from wide binaries found in the Gaia Catalog of Nearby Stars where one or both components have excessive astrometric noise o…
Validating AU Microscopii d with Transit Timing Variations
Barclay, Thomas; Triaud, Amaury H. M. J.; Dreizler, Stefan +31 more
AU Mic is a young (22 Myr), nearby exoplanetary system that exhibits excess transit timing variations (TTVs) that cannot be accounted for by the two known transiting planets nor stellar activity. We present the statistical "validation" of the tentative planet AU Mic d (even though there are examples of "confirmed" planets with ambiguous orbital pe…
A Survey for High-redshift Gravitationally Lensed Quasars and Close Quasar Pairs. I. The Discoveries of an Intermediately Lensed Quasar and a Kiloparsec-scale Quasar Pair at z 5
Fan, Xiaohui; Yang, Jinyi; Wang, Feige +1 more
We present the first results from a new survey for high-redshift (z ≳ 5) gravitationally lensed quasars and close quasar pairs. We carry out candidate selection based on the colors and shapes of objects in public imaging surveys, then conduct follow-up observations to confirm the nature of high-priority candidates. In this paper, we report the dis…
Stellar Rotation and Structure of the α Persei Complex: When Does Gyrochronology Start to Work?
Bouma, Luke G.; Boyle, Andrew W.
On the pre-main sequence, the rotation rates of Sun-like stars are dictated by the interplay between the protostellar disk and the star's contraction. At ages exceeding 100 Myr, magnetic spindown erases the initial stellar spin rate and enables rotation-based age dating (gyrochronology). The exact time at which the transition between these two reg…
TOI-3984 A b and TOI-5293 A b: Two Temperate Gas Giants Transiting Mid-M Dwarfs in Wide Binary Systems
Kobulnicky, Henry A.; Kowalski, Adam F.; Cochran, William D. +30 more
We confirm the planetary nature of two gas giants discovered by TESS to transit M dwarfs with stellar companions at wide separations. TOI-3984 A (J = 11.93) is an M4 dwarf hosting a short-period (4.353326 ± 0.000005 days) gas giant (M p = 0.14 ± 0.03 M J and R p = 0.71 ± 0.02 R J) with a wide-separat…
TOI-2525 b and c: A Pair of Massive Warm Giant Planets with Strong Transit Timing Variations Revealed by TESS
Trifonov, Trifon; Henning, Thomas; Kürster, Martin +44 more
The K-type star TOI-2525 has an estimated mass of M = ${0.849}_{-0.033}^{+0.024}$ M ⊙ and radius of R = ${0.785}_{-0.007}^{+0.007}$ R ⊙ observed by the TESS mission in 22 sectors (within sectors 1 and 39). The TESS light curves yield significant transit events of two companions, which show strong transit timing variations (TT…
Scaling K2. VI. Reduced Small-planet Occurrence in High-galactic-amplitude Stars
Rice, Malena; Howard, Andrew W.; Petigura, Erik A. +13 more
In this study, we performed a homogeneous analysis of the planets around FGK dwarf stars observed by the Kepler and K2 missions, providing spectroscopic parameters for 310 K2 targets -including 239 Scaling K2 hosts-observed with Keck/HIRES. For orbital periods less than 40 days, we found that the distribution of planets as a function of orbital pe…
Evidence That the Occurrence Rate of Hot Jupiters around Sun-like Stars Decreases with Stellar Age
Miyazaki, Shota; Masuda, Kento
We investigate how the occurrence rate of giant planets (minimum mass > 0.3 M Jup) around Sun-like stars depends on the age, mass, and metallicity of their host stars. We develop a hierarchical Bayesian framework to infer the number of planets per star (NPPS) as a function of both planetary and stellar parameters. The framework fully…
Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions
Butler, R. Paul; Vogt, Steven S.; Kane, Stephen R. +22 more
Directly imaging temperate rocky planets orbiting nearby, Sun-like stars with a 6 m class IR/O/UV space telescope, recently dubbed the Habitable Worlds Observatory, is a high-priority goal of the Astro2020 Decadal Survey. To prepare for future direct imaging (DI) surveys, the list of potential targets should be thoroughly vetted to maximize effici…
Astrometry and Photometry for ≈1000 L, T, and Y Dwarfs from the UKIRT Hemisphere Survey
Schneider, Adam C.; Vrba, Frederick J.; Munn, Jeffrey A. +5 more
We present the positions, proper motions, and near-infrared photometry for 966 known objects with spectral types later than M that were observed as part of the the UKIRT Hemisphere Survey (UHS). We augment the photometry and astrometry from UHS with information from Gaia DR3, Pan-STARRS DR2, and CatWISE 2020 to produce a database of homogeneous ph…