Subaru K ‐Band Spectroscopy of Low‐Mass Protostars in Taurus

Abstract

We present K-band spectra of five Class I objects in the Taurus molecular cloud. The high-sensitivity and high-spatial resolution observations using the Subaru Telescope enabled us to detect the emission lines of Brγ and H2 in four and two objects, respectively, and photospheric absorption lines in two objects. From the absorption lines, the effective temperature, stellar luminosity, and the amount of veiling were estimated for the two objects (IRAS 04016+2610 and IRAS 04248+2612). We conclude that the amount of circumstellar emission is much higher in IRAS 04016 (rK=7-10) than IRAS 04248 (rK~2), while the stellar properties are similar between the two objects. Apart from the stellar spectra, the nebular spectra were obtained for IRAS 04016 and IRAS 04248. The reflection nebulae of the Class I objects were verified from a spectroscopic viewpoint for the first time: we found that the nebular spectra are explained as the scattered light from the central young stellar objects with the difference of the line-of-sight extinction between the star and nebula, ΔAV~2-9 mag. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.