Distance Dependent Offsets between Parallaxes for Nearby Stars and Gaia DR1 Parallaxes

We use 612 single stars with previously published trigonometric parallaxes placing them within 25 pc to evaluate parallaxes released in Gaia's first data release (DR1). We find that the Gaia parallaxes are, on average, $0.24 \pm 0.02$ mas smaller than the weighted mean trigonometric parallax values for these stars in the solar neighborhood. We also find that the offset changes with distance out to 100 pc, in the sense that the closer the star, the larger the offset. We find no systematic trends in the parallax offsets with stellar $V$ magnitude, $V-K$ color, or proper motion. We do find that the offset is roughly twice as large for stars south of the ecliptic compared to those that are north.Comment: 14 pages, 2 figures, 3 tables, accepted for publication in ApJ Letter. The table 1 is available in its entirety in a machine-readable form in the online journa

Distance-dependent Offsets between Parallaxes for Nearby Stars and Gaia DR1 Parallaxes

We use 612 single stars with previously published trigonometric parallaxes placing them within 25 pc to evaluate parallaxes released in Gaia's first data release (DR1). We find that the Gaia parallaxes are, on average, 0.24 ± 0.02 mas smaller than the weighted mean trigonometric parallax values for these stars in the solar neighborhood. We also find that the offset changes with distance out to 100 pc, in the sense that the closer the star, the larger the offset. We find no systematic trends in the parallax offsets with stellar V magnitude, V − K color, or proper motion. We do find that the offset is roughly twice as large for stars south of the ecliptic compared to those that are north

THE SOLAR NEIGHBORHOOD. XXXV. DISTANCES TO 1404 M DWARF SYSTEMS WITHIN 25 PC IN THE SOUTHERN SKY

ABSTRACT , covering the entire M dwarf spectral sequence from M0.0 V through M9.5 V. This sample therefore provides a comprehensive snapshot of our current knowledge of the southern sky for the nearest M dwarfs that dominate the stellar population of the Galaxy. Roughly one-third of the 1748 systems, each of which has an M dwarf primary, have published high quality parallaxes, including 179 from the REsearch Consortium On Nearby Stars astrometry program. For the remaining systems, we offer photometric distance estimates that have well-calibrated errors. The bulk of these (∼700) are based on new V R I J KC KC photometry acquired at the CTIO/ SMARTS 0.9 m telescope, while the remaining 500 primaries have photographic plate distance estimates calculated using SuperCOSMOS B R I J F 59 IVN photometry. Confirmed and candidate subdwarfs in the sample have been identified, and a census of companions is included

THE SOLAR NEIGHBORHOOD. XXXV. DISTANCES TO 1404 M DWARF SYSTEMS WITHIN 25 PC IN THE SOUTHERN SKY

ABSTRACT , covering the entire M dwarf spectral sequence from M0.0 V through M9.5 V. This sample therefore provides a comprehensive snapshot of our current knowledge of the southern sky for the nearest M dwarfs that dominate the stellar population of the Galaxy. Roughly one-third of the 1748 systems, each of which has an M dwarf primary, have published high quality parallaxes, including 179 from the REsearch Consortium On Nearby Stars astrometry program. For the remaining systems, we offer photometric distance estimates that have well-calibrated errors. The bulk of these (∼700) are based on new V R I J KC KC photometry acquired at the CTIO/ SMARTS 0.9 m telescope, while the remaining 500 primaries have photographic plate distance estimates calculated using SuperCOSMOS B R I J F 59 IVN photometry. Confirmed and candidate subdwarfs in the sample have been identified, and a census of companions is included