URAT Parallax Catalog (UPC)

TL;DR

The URAT Parallax Catalog (UPC) provides over 112,000 stellar parallaxes, including many with first-time measurements, derived from USNO URAT data, offering a significant resource for stellar distance and motion studies.

Contribution

This paper presents the largest parallax catalog since Hipparcos, including new measurements and improved data reduction techniques for northern hemisphere stars.

Findings

Contains 112,177 parallaxes for northern stars.

Includes 53,500 first-time trigonometric parallaxes.

Achieves mean parallax errors of 10.8 mas and 4.3 mas for two star groups.

Abstract

The URAT Parallax Catalog (UPC) consists of 112,177 parallaxes. The catalog utilizes all Northern Hemisphere exposures from the United States Naval Observatory (USNO) Robotic Astrometric Telescope (URAT) obtained between April 2012 and June 2015. Relative parallaxes are converted to absolute using photometric distance estimates of UCAC4 reference stars. There are 2 groups of stars in this catalog: 1) 58,677 stars with prior published trigonometric parallax (Hipparcos, Yale Parallax Catalog, MEarth project and SIMBAD), and 2) 53,500 stars with first time trigonometric parallaxes as obtained from URAT data. More stringent selection criteria have been applied for group 2 then for group 1 in order to keep the rate of false detections low. The mean error in UPC parallaxes is 10.8 and 4.3 mas for groups 1 and 2, respectively. All stars in UPC are north of -13 deg Dec and between 6.5 and 17 mag. The UPC is published by CDS as catalog I/333 and the acronym has been registered with the IAU. The Finch & Zacharias (2016, in press with AJ) paper describes the data, reductions, and results of an about 1000 star subset (stars within 40 pc of the Sun) of the entire UPC. The UPC also provides accurate positions and proper motions on the ICRS. This is the largest parallax catalog published since the Hipparcos Catalog.