The RKSTAR Concert — A RECONS Survey of the 5000 Nearest K Dwarfs

The RKSTAR (RECONS K Stars) Survey targets the 5000 nearest K dwarfs, all within 50 parsecs of the Sun. This is a critical sample for astrophysical studies and exoplanet searches, addressing science questions from the star formation history in the Milky Way to potential locations for life-bearing worlds. To paint a complete portrait of the sample, RECONS (REsearch Consortium On Nearby Stars, www.recons.org) is conducting four systematic surveys of these K dwarfs. First is the spectroscopic Characterization Survey, carried out using the CHIRON high-resolution spectrograph on the SMARTS 1.5m at CTIO. The spectra provide accurate temperatures, metallicities, and measurements of activity indices that are used to estimate ages. The Wide Field Survey targets all companions at separations larger than about 1 arcsecond, with a rich suite of stellar companions revealed using Gaia results and cataloged companions from the Washington Double Stars Catalog — hundreds of companions have been identified out to 1000 AU. The Speckle Survey reaches for stellar companions from 0.5-100 AU, comparable to the scale of our Solar System, using cameras on the Lowell Discovery Telescope and Gemini North and South. More than 150 stellar companions, many of them new discoveries, have already been found and most orbit within 5 AU of the K dwarfs. The Radial Velocity Survey utilizes CHIRON on the SMARTS 1.5m to reveal stars, brown dwarfs, and jovian exoplanets orbiting the K dwarfs within 3 AU. Several new planets have already been discovered, and dozens of orbits for more massive companions have been fully mapped. Together, the four surveys will provide an unprecedented dataset describing the characteristics and companions to the stars that make up 12% of all stars in the solar neighborhood.

This effort has been supported by the NSF through grants AST-1517413 and AST-1910130, via observations made possible by the SMARTS Consortium.