The Solar Neighborhood XXXVIII. Results from the CTIO/SMARTS 0.9m: Trigonometric Parallaxes for 151 Nearby M Dwarf Systems

TL;DR

This paper reports 160 new trigonometric parallaxes for 151 M dwarf systems, significantly expanding the catalog of nearby stars within 25 parsecs, and identifies new binary systems and variability among these stars.

Contribution

It provides a substantial increase in the number of accurately measured parallaxes for southern M dwarf systems within 25 parsecs, including new binary discoveries and variability data.

Findings

82% of the stars are within 25 pc

16 systems are newly discovered binaries

Six stars vary by more than 20 mmag

Abstract

We present 160 new trigonometric parallaxes for 151 M dwarf systems from the REsearch Consortium On Nearby Stars (RECONS) group's long-term astrometry/photometry program at the CTIO/SMARTS 0.9m telescope. Most systems (124 or 82%) are found to lie within 25 pc. The stars have 119 mas/yr < mu < 828 mas/yr and 3.85 < (V-K) < 8.47. Among these are 58 systems from the SuperCOSMOS-RECONS (SCR) search, discovered via our proper motion trawls of the SuperCOSMOS digitized archival photographic plates, while the remaining stars were suspected via photometric distance estimates to lie nearby. Sixteen are systems that are newly discovered via astrometric perturbations to be binaries, many of which are ideal for accurate mass determinations due to their proximity and orbital periods on the order of a decade. A variability analysis of the stars presented, two-thirds of which are new results, shows six of the stars to vary by more than 20 mmag. This effort brings the total number of parallaxes for M dwarf systems measured by RECONS to nearly 500 and increases by 26% the number of southern M dwarf systems with accurate trigonometric parallaxes placing them within 25 pc.