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Optical Studies of 15 Hard X-Ray Selected Cataclysmic Binaries
DOI: 10.3847/1538-3881/aabfd0 Bibcode: 2018AJ....155..247H

Thorstensen, John R.; Halpern, Jules P.; Buckley, David A. H. +5 more

We conducted time-resolved optical spectroscopy and/or time-series photometry of 15 cataclysmic binaries that were discovered in hard X-ray surveys by the Swift Burst Alert Telescope and the International Gamma-Ray Astrophysics Laboratory, with the goal of measuring their orbital periods and searching for spin periods. Four of the objects in this …

2018 The Astronomical Journal
Gaia 25
A Comparative Study of WASP-67 b and HAT-P-38 b from WFC3 Data
DOI: 10.3847/1538-3881/aaa0c7 Bibcode: 2018AJ....155...55B

Deming, Drake; Stevenson, Kevin B.; Wakeford, Hannah R. +12 more

Atmospheric temperature and planetary gravity are thought to be the main parameters affecting cloud formation in giant exoplanet atmospheres. Recent attempts to understand cloud formation have explored wide regions of the equilibrium temperature-gravity parameter space. In this study, we instead compare the case of two giant planets with nearly id…

2018 The Astronomical Journal
eHST 25
Models of Rosetta/OSIRIS 67P Dust Coma Phase Function
DOI: 10.3847/1538-3881/aae526 Bibcode: 2018AJ....156..237M

Lamy, P. L.; Lara, L. M.; Bertaux, J. -L. +39 more

The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images. This function shows a deep minimum at phase angles near 100°, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly oriented aggregate …

2018 The Astronomical Journal
Rosetta 24
Binary Red Supergiants: A New Method for Detecting B-type Companions
DOI: 10.3847/1538-3881/aae4e0 Bibcode: 2018AJ....156..225N

Massey, Philip; Levesque, Emily M.; Neugent, Kathryn F.

With the exception of a few well-known and studied systems, the binary population of red supergiants (RSGs) remains relatively uncharacterized. Famous systems such as VV Cep, 31 Cyg, and ζ Aur contain RSG + B star binaries, and here we explore whether B stars are the main type of companion we expect from an evolutionary point of view. Using the Ge…

2018 The Astronomical Journal
Gaia 24
Li in Open Clusters: Cool Dwarfs in the Young, Subsolar-metallicity Cluster M35 (NGC 2168)
DOI: 10.3847/1538-3881/aacb1f Bibcode: 2018AJ....156...37A

Twarog, Bruce A.; Anthony-Twarog, Barbara J.; Deliyannis, Constantine P. +4 more

Hydra spectra of 85 G-K dwarfs in the young cluster M35 near the Li 6708 Å line region are analyzed. From velocities and Gaia astrometry, 78 are likely single-star members that, combined with previous work, produce 108 members with T eff ranging from 6150 to 4000 K as defined by multicolor, broadband photometry, E(B - V) = 0.20, and [Fe…

2018 The Astronomical Journal
Gaia 23
Cepheids in M31: The PAndromeda Cepheid Sample
DOI: 10.3847/1538-3881/aad40f Bibcode: 2018AJ....156..130K

Lee, Chien-Hsiu; Bender, Ralf; Seitz, Stella +15 more

We present the largest Cepheid sample in M31 based on the complete Pan-STARRS1 survey of Andromeda (PAndromeda) in the r P1, i P1, and g P1 bands. We find 2686 Cepheids with 1662 fundamental-mode Cepheids, 307 first-overtone Cepheids, 278 type II Cepheids, and 439 Cepheids with undetermined Cepheid type. Using the …

2018 The Astronomical Journal
Gaia eHST 23
The Nucleus of Active Asteroid 311P/(2013 P5) PANSTARRS
DOI: 10.3847/1538-3881/aabdee Bibcode: 2018AJ....155..231J

Mutchler, Max; Jewitt, David; Agarwal, Jessica +3 more

The unique inner-belt asteroid 311P/PANSTARRS (formerly P/2013 P5) is notable for its sporadic, comet-like ejection of dust in nine distinct epochs spread over ∼250 days in 2013. This curious behavior has been interpreted as the product of localized, equatorward landsliding from the surface of an asteroid rotating at the brink of instability. We o…

2018 The Astronomical Journal
eHST 23
Zodiacal Light Beyond Earth Orbit Observed with Pioneer 10
DOI: 10.3847/1538-3881/aad0f0 Bibcode: 2018AJ....156...86M

Matsumoto, T.; Pyo, J.; Tsumura, K. +1 more

We reanalyze the Imaging Photopolarimeter data from Pioneer 10 to study the zodiacal light in the B and R bands beyond Earth orbit, applying an improved method to subtract integrated star light (ISL) and diffuse Galactic light (DGL). We found that there exists a significant instrumental offset, making it difficult to examine the absolute sky brigh…

2018 The Astronomical Journal
eHST 22
The High Cadence Transit Survey (HiTS): Compilation and Characterization of Light-curve Catalogs
DOI: 10.3847/1538-3881/aadfd8 Bibcode: 2018AJ....156..186M

Pignata, Giuliano; Galbany, Lluis; González-Gaitán, Santiago +12 more

The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the ana…

2018 The Astronomical Journal
Gaia 22
LHS 1610A: A Nearby Mid-M Dwarf with a Companion That Is Likely a Brown Dwarf
DOI: 10.3847/1538-3881/aaaa65 Bibcode: 2018AJ....155..125W

Latham, David W.; Berlind, Perry; Calkins, Michael L. +7 more

We present the spectroscopic orbit of LHS 1610A, a newly discovered single-lined spectroscopic binary with a trigonometric distance placing it at 9.9 ± 0.2 pc. We obtained spectra with the TRES instrument on the 1.5 m Tillinghast Reflector at the Fred Lawrence Whipple Observatory located on Mt. Hopkins in AZ. We demonstrate the use of the TiO mole…

2018 The Astronomical Journal
Gaia 22