Search Publications

The Hawaii Infrared Parallax Program. III. 2MASS J0249-0557 c: A Wide Planetary-mass Companion to a Low-mass Binary in the β Pic Moving Group
DOI: 10.3847/1538-3881/aacbc2 Bibcode: 2018AJ....156...57D

Kratter, Kaitlin M.; Dupuy, Trent J.; Kraus, Adam L. +6 more

We have discovered a wide planetary-mass companion to the β Pic moving group member 2MASS J02495639-0557352 (M6 VL-G) using Canada-France-Hawaii Telescope/WIRCam astrometry from the Hawaii Infrared Parallax Program. In addition, Keck laser guide star adaptive optics aperture-masking interferometry shows that the host is itself a tight binary. Alto…

2018 The Astronomical Journal
Gaia 32
First Data Release of the All-sky NOAO Source Catalog
DOI: 10.3847/1538-3881/aad68f Bibcode: 2018AJ....156..131N

Nidever, David L.; Olsen, Knut; Dey, Arjun +6 more

Most of the sky has been imaged with NOAO’s telescopes from both hemispheres. While the large majority of these data were obtained for PI-led projects and almost all of the images are publicly available, only a small fraction have been released to the community via well-calibrated and easily accessible catalogs. We are remedying this by creating a…

2018 The Astronomical Journal
Gaia 32
A New Dark Vortex on Neptune
DOI: 10.3847/1538-3881/aaa6d6 Bibcode: 2018AJ....155..117W

de Pater, Imke; Wong, Michael H.; Baranec, Christoph +12 more

An outburst of cloud activity on Neptune in 2015 led to speculation about whether the clouds were convective in nature, a wave phenomenon, or bright companions to an unseen dark vortex (similar to the Great Dark Spot studied in detail by Voyager 2). The Hubble Space Telescope (HST) finally answered this question by discovering a new dark vortex at…

2018 The Astronomical Journal
eHST 32
A Tale of “Two” Comets: The Primary Volatile Composition of Comet 2P/Encke Across Apparitions and Implications for Cometary Science
DOI: 10.3847/1538-3881/aae0f7 Bibcode: 2018AJ....156..251R

Vervack, Ronald J., Jr.; Kawakita, Hideyo; DiSanti, Michael A. +5 more

The highly favorable 2017 apparition of 2P/Encke allowed the first comprehensive comparison of primary volatile abundances in a given comet across multiple apparitions. This apparition offered opportunities to address pressing questions in cometary science, including investigating evolutionary and/or heliocentric distance (R h) effects …

2018 The Astronomical Journal
Rosetta 31
Improving Gaia Parallax Precision with a Data-driven Model of Stars
DOI: 10.3847/1538-3881/aad7bf Bibcode: 2018AJ....156..145A

Bovy, Jo; Leistedt, Boris; Hogg, David W. +2 more

Converting a noisy parallax measurement into a posterior belief over distance requires inference with a prior. Usually, this prior represents beliefs about the stellar density distribution of the Milky Way. However, multiband photometry exists for a large fraction of the Gaia-TGAS Catalog and is incredibly informative about stellar distances. Here…

2018 The Astronomical Journal
Gaia 31
The Performance of the Robo-AO Laser Guide Star Adaptive Optics System at the Kitt Peak 2.1 m Telescope
DOI: 10.3847/1538-3881/aa9be6 Bibcode: 2018AJ....155...32J

Kulkarni, S. R.; Baranec, Christoph; Duev, Dmitry A. +5 more

Robo-AO is an autonomous laser guide star adaptive optics (AO) system recently commissioned at the Kitt Peak 2.1 m telescope. With the ability to observe every clear night, Robo-AO at the 2.1 m telescope is the first dedicated AO observatory. This paper presents the imaging performance of the AO system in its first 18 months of operations. For a m…

2018 The Astronomical Journal
Gaia 31
Transformation of HST WFC3/UVIS Filters to the Standard BVI System
DOI: 10.3847/1538-3881/aaedb8 Bibcode: 2018AJ....156..296H

Harris, William E.

Empirical transformations of selected broadband filters in the Hubble Space Telescope Wide Field Camera 3 (WFC3)/UVIS camera into the BVI system are derived. These conversions employ photometry of stars in a standard field in the globular cluster 47 Tucanae that has repeatedly been imaged with both the WFC3 and Advanced Camera for Surveys (ACS) ca…

2018 The Astronomical Journal
eHST 30
Cloud Atlas: Rotational Modulations in the L/T Transition Brown Dwarf Companion HN Peg B
DOI: 10.3847/1538-3881/aaabbd Bibcode: 2018AJ....155..132Z

Schneider, Glenn; Metchev, Stanimir; Apai, Dániel +11 more

Time-resolved observations of brown dwarfs’ rotational modulations provide powerful insights into the properties of condensate clouds in ultra-cool atmospheres. Multi-wavelength light curves reveal cloud vertical structures, condensate particle sizes, and cloud morphology, which directly constrain condensate cloud and atmospheric circulation model…

2018 The Astronomical Journal
eHST 30
Starspot Occultations in Infrared Transit Spectroscopy: The Case of WASP-52b
DOI: 10.3847/1538-3881/aac6db Bibcode: 2018AJ....156..124B

Deming, Drake; Stevenson, Kevin B.; López-Morales, Mercedes +7 more

Stellar activity is one of the main obstacles to high-precision exoplanet observations and has motivated extensive studies in detection and characterization problems. Most efforts focused on unocculted starspots in optical transit spectrophotometry, while the impact of starspot crossings is assumed to be negligible in the near-infrared. Here, we p…

2018 The Astronomical Journal
eHST 29
High-time-resolution Photometry of AR Scorpii: Confirmation of the White Dwarf’s Spin-down
DOI: 10.3847/1538-3881/aad5dd Bibcode: 2018AJ....156..150S

Garnavich, Peter; Littlefield, Colin; Myers, Gordon +3 more

The unique binary AR Scorpii consists of an asynchronously rotating, magnetized white dwarf (WD) that interacts with its red-dwarf companion to produce a large-amplitude, highly coherent pulsation every 1.97 minutes. Over the course of two years, we obtained 39 hours of time-resolved, optical photometry of AR Sco at a typical cadence of 5 s to stu…

2018 The Astronomical Journal
Gaia 29