Fundamental Properties of Low-Mass Stars andBrown Dwarfs

摘要

Precise measurements of the fundamental properties of low-mass stars and brown dwarfsare key to understanding the physics underlying their formation and evolution. While there has beengreat progress over the last decade in studying the bulk spectrophotometric properties of low-massobjects, direct determination of their masses, radii, and temperatures have been very sparse. Thus,theoretical predictions of low-mass evolution and ultracool atmospheres remain to be rigorouslytested. The situation is alarming given that such models are widely used, from the determination ofthe low-mass end of the initial mass function to the characterization of exoplanets. An increasing number of mass, radius, and age determinations are placing critical constraints onthe physics of low-mass objects. A wide variety of approaches are being pursued, including eclipsingbinary studies, astrometric-spectroscopic orbital solutions, interferometry, and characterization ofbenchmark systems. In parallel, many more systems suitable for concerted study are now beingfound, thanks to new capabilities spanning both the very widest (all-sky surveys) and very narrowest(diffraction-limited adaptive optics) areas of the sky. This Cool Stars 15 splinter session highlightedthe current successes and limitations of this rapidly growing area of precision astrophysics.