A Young Star near the Hydrogen‐burning Limit

Abstract

We show that V410 X-ray 3, toward the L1495E star-forming complex, is an object with a mass of 0.08-0.15 M☉ and an age of ~1 Myr. Nonetheless, it has emerged from its natal cloud and can be studied in detail throughout the optical and near-infrared, providing new insights into the character of very young and low-mass objects. It has spectral characteristics intermediate between those of late dwarfs and giants (e.g., first-overtone CO typical of an M6 dwarf, but K I, Na I, and TiO/VO typical of an M6 giant and CaH intermediate between the luminosity classes). Its optical and IR photometric colors are consistent with those of an M6 dwarf. If the latest theoretical evolutionary tracks are valid at young ages and low masses, it appears that the hydrogen-burning limit at an age of ~1 Myr occurs at a spectral type of M6-M7.