Abstract
The emission spectra of the nebular variables of the Τ Tauri class, and of the related dwarf stars in dark nebulae, have been described by A. H. Joy.1»2 They are similar to the spectra of such disturbed regions of the sun as solar flares or the chromosphere. High-excitation lines are seen, such as He i, even He π, together with strong H, Ca n, Fe n, and some forbidden lines, superposed on an underlying late-type dwarf absorption spectrum. Joy,2 in his Table 2, remarks that in 11 out of 40 stars the absorption spectrum is partially or heavily obscured or filled in by a continuous emission. J. L. Greenstein3 found that the apparent luminosity of several of the Τ Tauri group (BD 6° 1253, R Mon, R CrA) was greater by about one magnitude than would be predicted from the spectroscopic luminosity, distance, and obscuration of the stars. For example, in spite of their location in dark lanes, the mean obscuration estimated by Joy2 is less than one magnitude. This is small compared to the total absorption in these dark clouds, and would not suggest the strong observed interaction of star and dense interstellar material.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
