Title:

The Youngest Optically Visible Stars in Taurus-Auriga 



Russel White
Caltech


Abstract:


We present high resolution optical spectra of 36 stars in
Taurus-Auriga whose circumstellar environment suggests that
they are younger than optically revealed T Tauri stars.
Many of the stars are seen only via scattered light.  For
28 of these 36 stars, our measurements are the first high
dispersion optical spectra ever obtained.  Photospheric
features are detected in 11/15 Class I stars (40\% of known
Taurus Class Is) and 21/21 Class II stars.  These spectra,
incombination with previous measurements, are used to
search for differences between stars which power
Herbig-Haro flows and stars which do not, and to reassess
the evolutionary state of so-called protostars (Class I
stars) relative to optically revealed T Tauri stars (Class
II stars).