Trigonometric Parallaxes of Two T Dwarfs With Keck and ShaneAO Astrometry
- 1 August 2021
- journal article
- research article
- Published by IOP Publishing in Publications of the Astronomical Society of the Pacific
- Vol. 133 (1026), 084401
- https://doi.org/10.1088/1538-3873/ac17e3
Abstract
We present trigonometric parallax and proper motion measurements for two T-type brown dwarfs. We derive our measurements from infrared laser guide star adaptive optics observations spanning five years from the ShaneAO/SHARCS and NIRC2/medium-cam instruments on the Shane and Keck telescopes, respectively. To improve our astrometric precision, we measure and apply a distortion correction to our fields for both instruments. We also transform the Keck and ShaneAO astrometric reference frames onto the ICRS using five-parameter parallax and proper motion solutions for background reference stars from Gaia DR2. Fitting for parallax and proper motion, we measure parallaxes of 73.5 +/- 9.2 mas and 70.1 +/- 6.7 mas for WISEJ19010703+47181688 (WISE1901) and WISEJ21543294+59421370 (WISE2154), respectively. We utilize Monte Carlo methods to estimate the error in our sparse field methods, taking into account overfitting and differential atmospheric refraction. Comparing to previous measurements in the literature, all of our parallax and proper motion values fall within 2 sigma of the published measurements, and 4 of 6 measurements are within 1 sigma. These data are among the first parallax measurements of these T dwarfs and serve as precise measurements for calibrating stellar formation models. These two objects are the first results of an ongoing survey of T dwarfs with Keck/NIRC2 and the Shane Adaptive Optics system at Lick Observatory.Keywords
Funding Information
- Lawrence Livermore National Laboratory (20-ERD-046)
This publication has 33 references indexed in Scilit:
- THE FIRST HUNDRED BROWN DWARFS DISCOVERED BY THE WIDE-FIELD INFRARED SURVEY EXPLORER ( WISE )The Astrophysical Journal Supplement Series, 2011
- IMPROVING GALACTIC CENTER ASTROMETRY BY REDUCING THE EFFECTS OF GEOMETRIC DISTORTIONThe Astrophysical Journal, 2010
- Discovery of 11 New T Dwarfs in the Two Micron All Sky Survey, Including a Possible L/T Transition BinaryThe Astronomical Journal, 2007
- The UKIRT Infrared Deep Sky Survey (UKIDSS)Monthly Notices of the Royal Astronomical Society, 2007
- The Two Micron All Sky Survey (2MASS)The Astronomical Journal, 2006
- The NIRSPEC Brown Dwarf Spectroscopic Survey. I. Low‐Resolution Near‐Infrared SpectraThe Astrophysical Journal, 2003
- Cosmic‐Ray Rejection by Laplacian Edge DetectionPublications of the Astronomical Society of the Pacific, 2001
- First Light Adaptive Optics Images from the Keck II Telescope: A New Era of High Angular Resolution ImageryPublications of the Astronomical Society of the Pacific, 2000
- Differential Atmospheric Refraction and Limitations on the Relative Astrometric Accuracy of Large TelescopesPublications of the Astronomical Society of the Pacific, 1998
- Study of Degeneracy in Very Light Stars.The Astronomical Journal, 1962