Ultraviolet-Selected Field and Pre-Main-Sequence Stars Towards Taurus and Upper Scorpius - Astrophysics > Solar and Stellar AstrophysicsReportar como inadecuado




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Abstract: We have carried out a Galaxy Evolution Explorer GALEX Cycle 1 guestinvestigator program covering 56 square degrees near the Taurus T associationand 12 square degrees along the northern edge of the Upper Scorpius OBassociation. We combined photometry in the GALEX FUV and NUV bands with datafrom the Two Micron All Sky Survey to identify candidate young <100 Myr oldstars as those with an ultraviolet excess relative to older main sequencestars. Follow-up spectroscopy of a partial sample of these candidates suggest 5new members of Taurus, with 8-20 expected from additional observations, and 5new members of Upper Scorpius, with 3-6 expected from additional observations.These candidate new members appear to represent a distributed, non-clusteredpopulation in either region, although our sample statistics are as of yet toopoor to constrain the nature or extent of this population. Rather, our studydemonstrates the ability of GALEX observations to identify young stellarpopulations distributed over a wide area of the sky. We also highlight thenecessity of a better understanding of the Galactic ultraviolet sourcepopulation to support similar investigations. In particular, we report a largepopulation of stars with an ultraviolet excess but no optical indicators ofstellar activity or accretion, and briefly argue against severalinterpretations of these sources.



Autor: Krzysztof Findeisen, Lynne Hillenbrand

Fuente: https://arxiv.org/







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