THE SOLAR NEIGHBORHOOD. XXXVIII. RESULTS FROM THE CTIO/SMARTS 0.9 m: TRIGONOMETRIC PARALLAXES FOR 151 NEARBY M DWARF SYSTEMS

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 0.9 m telescope. Most systems (124 or 82%) are found to lie within 25 pc. The stars have 119 mas yr -1  μ  828 mas yr −1 and 3.85. Among these are 58 systems from the SuperCOSMOS-RECONS 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 systems were 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.

The stellar rotation–activity relationship in fully convective M dwarfs

“…X-ray fluxes are provided in both Chandra's 0.5-8.0 keV band and ROSAT's 0.1-2.4 keV band, with L X /L bol provided in the latter band, following historical standard. Bolometric corrections were calculated from the V − J colour and the relations in Mann et al (2015Mann et al ( , 2016, allowing bolometric fluxes to be calculated for all stars, with bolometric luminosities then calculated using distances from parallaxes (van Altena et al 1995;Benedict et al 1999;Henry et al 2006;Riedel et al 2010;Lépine & Gaidos 2011;Dittmann et al 2014;David & Hillenbrand 2015;Winters et al 2015;Finch & Zacharias 2016;Weinberger et al 2016;Winters et al 2017). Note that because L X /L bol is independent of distance, uncertainties in the parallax do not contribute to the uncertainties on this parameter.…”

The Solar Neighborhood. XLIII. Discovery of New Nearby Stars with μ < 0.″18 yr−1 (TINYMO Sample)

“…Analysis of some stars found in the TINYMO sample also appears in Riedel et al (2014) and Riedel et al (2017b), and objects with proper motions higher than 0.18 ′′ yr −1 were folded into the study published in Winters et al (2017).…”

A temperate rocky super-Earth transiting a nearby cool star

“…The distance to LHS 1140 has been measured through trigonometric parallax to be 12.47 ± 0.42 parsecs (ref. 14). Combined with the 2MASS K s magnitude 15 and empirically determined stellar relationships 16,17 , we estimate the stellar mass to be 14.6% that of the Sun and the stellar radius to be 18.6% that of the Sun.…”