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Dancing Twins: Stellar Hierarchies That Formed Sequentially?
Tokovinin, Andrei
This paper draws attention to the class of resolved triple stars with moderate ratios of inner and outer periods (possibly in a mean motion resonance) and nearly circular, mutually aligned orbits. Moreover, stars in the inner pair are twins with almost identical masses, while the mass sum of the inner pair is comparable to the mass of the outer co…
A New Hyper-runaway Star Discovered from LAMOST and Gaia: Ejected Almost in the Galactic Rotation Direction
Zhao, Gang; Zhao, Jing-Kun; Huang, Yang +11 more
In this paper, we report the discovery of a new late-B-type unbound hyper-runaway star (LAMOST-HVS4) from the LAMOST spectroscopic surveys. According to its atmospheric parameters, it is either a B-type main-sequence (MS) star or a blue horizontal branch (BHB) star. Its Galactocentric distance and velocity are 30.3 ± 1.6 kpc and 586 ± 7 km s-…
Planetary Candidates from K2 Campaign 16
Henning, Thomas; Schlieder, Joshua E.; Fulton, Benjamin J. +20 more
Given that Campaign 16 of the K2 mission is one of just two K2 campaigns observed so far in “forward-facing” mode, which enables immediate follow-up observations from the ground, we present a catalog of interesting targets identified through photometry alone. Our catalog includes 30 high-quality planet candidates (showing no signs of being non-pla…
Direct Imaging of the HD 35841 Debris Disk: A Polarized Dust Ring from Gemini Planet Imager and an Outer Halo from HST/STIS
Duchêne, Gaspard; Esposito, Thomas M.; Oppenheimer, Rebecca +55 more
We present new high resolution imaging of a light-scattering dust ring and halo around the young star HD 35841. Using spectroscopic and polarimetric data from the Gemini Planet Imager in H-band (1.6 µm), we detect the highly inclined (i = 85°) ring of debris down to a projected separation of ∼12 au (∼0.″12) for the first time. Optical imagin…
Discovery of a Transiting Adolescent Sub-Neptune Exoplanet with K2
Vanderburg, Andrew; Bieryla, Allyson; Latham, David W. +19 more
The role of stellar age in the measured properties and occurrence rates of exoplanets is not well understood. This is in part due to a paucity of known young planets and the uncertainties in age-dating for most exoplanet host stars. Exoplanets with well-constrained ages, particularly those which are young, are useful as benchmarks for studies aimi…
The Gas Composition and Deep Cloud Structure of Jupiter's Great Red Spot
Wong, M. H.; Orton, G. S.; de Pater, I. +3 more
We have obtained high-resolution spectra of Jupiter’s Great Red Spot (GRS) between 4.6-5.4 µm using telescopes on Mauna Kea to derive gas abundances and to constrain its cloud structure between 0.5-5 bars. We used line profiles of deuterated methane (CH3D) at 4.66 µm to infer the presence of an opaque cloud at 5 ± 1 bars. Fr…
The Warm Neptunes around HD 106315 Have Low Stellar Obliquities
Vanderburg, Andrew; Bieryla, Allyson; Latham, David W. +8 more
We present the obliquity of the warm Neptune HD 106315c measured via a series of spectroscopic transit observations. HD 106315c is a 4.4 R Earth warm Neptune orbiting a moderately rotating late F star with a period of 21.05 days. HD 106315 also hosts a 2.5 R Earth super-Earth on a 9.55 day orbit. Our Doppler tomographic analy…
Fundamental Properties of Co-moving Stars Observed by Gaia
Faherty, Jacqueline K.; Gagné, Jonathan; Bochanski, John J. +5 more
We have estimated fundamental parameters for a sample of co-moving stars observed by Gaia and identified by Oh et al. We matched the Gaia observations to the 2MASS and Wide-Field Infrared Survey Explorer catalogs and fit MIST isochrones to the data, deriving estimates of the mass, radius, [Fe/H], age, distance, and extinction to 9754 stars in the …
Memberships of the Open Cluster NGC 6405 Based on a Combined Method: Gaussian Mixture Model and Random Forest
Gao, Xinhua
This paper presents a combined method of Gaussian mixture model and random forest to compute membership probabilities of stars by using large, high-dimensional data sets. A significant advantage of this method is that it allows us to easily identify likely cluster members in large data sets starting from small training samples. As a benchmark, we …
Four New Eclipsing Mid M-dwarf Systems from the New Luyten Two Tenths Catalog
Latham, David W.; Berlind, Perry; Calkins, Michael L. +7 more
Using data from the MEarth-North and MEarth-South transit surveys, we present the detection of eclipses in four mid M-dwarf systems: LP 107-25, LP 261-75, LP 796-24, and LP 991-15. Combining the MEarth photometry with spectroscopic follow-up observations, we show that LP 107-25 and LP 796-24 are short-period (1.388 and 0.523 day, respectively) ecl…