Paper detail

Parallax Results From URAT Epoch Data

We present 1103 trigonometric parallaxes and proper motions from the United States Naval Observatory (USNO) Robotic Astrometric Telescope (URAT) observations taken at the Naval Observatory Flagstaff Station (NOFS) over a 3 year period from April 2012 to June 2015 covering the entire sky north of about minus 10 deg declination. We selected 2 samples previously suspected nearby stars from known photometric distances and stars showing a large, significant parallax signature in URAT epoch data without any prior selection criteria. All systems presented in this paper have an observed parallax greater than equal to 40 mas with no previous published trigonometric parallax. The formal errors on these weighted parallax solutions are mostly between 4 and 10 mas. This sample gives a significant (order 50%) increase to the number of known systems having a trigonometric parallax to be within 25 pc of the Sun (without applying Lutz Kelker bias corrections). A few of these are found to be within 10 pc. Many of these new nearby stars display a total proper motion of less than 200 mas per year. URAT parallax results have been verified against Hipparcos and Yale data for stars in common. The publication of all significant parallax observations from URAT data is in preparation for CDS.