BD +33 2642 : a galactic halo blue star observed by IUE.

Abstract

IUE observations of the high luminosity Population II blue star BD plus 33 deg 2642 have been obtained at high resolution in the short wavelength range. The star lies at a distance of 8 kpc and has a galactic latitude plus 51 deg. The stellar spectrum shows the effect of mass loss in the highly ionized resonance lines of C IV, Si III, and Si IV. An upper limit for mass loss has been calculated to be M equals 4.7 x 10 to the -8th solar masses per year. The velocity of microturbulence of Fe III photospheric lines is 2.3 km/s. The interstellar lines are split into at least two components. No high ionization stages are found at the low velocity component; nor can they be detected in the higher velocity clouds, because of mixing with the corresponding stellar lines.