The UV Perspective of Low-Mass Star Formation

Abstract

The formation of low-mass (<inline-formula> <math display="inline"> <semantics> <mrow> <msub> <mi>M</mi> <mo>★</mo> </msub> <mo>≲</mo> <mn>2</mn> <mspace width="0.166667em"></mspace> <msub> <mi>M</mi> <mo>⊙</mo> </msub> </mrow> </semantics> </math> </inline-formula>) stars in molecular clouds involves accretion disks and jets, which are of broad astrophysical interest. Accreting stars represent the closest examples of these phenomena. Star and planet formation are also intimately connected, setting the starting point for planetary systems like our own. The ultraviolet (UV) spectral range is particularly suited for studying star formation, because virtually all relevant processes radiate at temperatures associated with UV emission processes or have strong observational signatures in the UV range. In this review, we describe how UV observations provide unique diagnostics for the accretion process, the physical properties of the protoplanetary disk, and jets and outflows. Keywords: star formation; ultraviolet; low-mass stars