Speaker: Dr. Todd Henry, Georgia State University & RECONS Institute

Title: Exploring 86% of the Star Systems in the Universe
Abstract: Most of the stars in the Universe are smaller and cooler than our Sun. A full 86% of stars in the solar neighborhood, and presumably throughout our Milky Way and other galaxies, are described by astronomers as “K dwarfs” or “M dwarfs” that range in mass from 80% down to 8% that of our Sun. It is on planets orbiting these stars where humanity’s search is likely to reveal life beyond Earth.

The RECONS (REsearch Consortium On Nearby Stars, www.recons.org) is creating the world’s best lists of K dwarfs within 50 parsecs and M dwarfs within 25 parsecs. Each sample contains about 4000 stellar systems, providing key target lists for astrophysical studies, exoplanet searches, and ultimately, life. I’ll describe our exploration of these K and M dwarf neighbors to the Sun, including their activity, ages, and long-term cycles like our star’s sunspot cycle. I’ll touch on surprising results about their companions — using various techniques to discover myriad stellar companions, very few brown dwarfs, and suites of exoplanets — and we’ll examine their orbital architectures. Much of our work takes advantage of the 1.5m and 0.9m SMARTS telescopes at CTIO, where we have had programs running since 1999. After a quarter century of observations, we have learned a few things …