Hubble Space Telescope Spectroscopy of Eta Carinae and Chi Lupi

Eta Carinae is a super-massive, super-luminous star. It is surrounded by a bipolar nebula, the "Homunculus", and several blobs of ejected gas which are the source of a complex emission-line spectrum. This thesis presents results from spectroscopic investigations of the star and its surroundings, performed with the Space Telescope Imaging Spectrograph (STIS) and the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope (HST). The age of the equatorial disk in the Homunculus has been studied by measurements of radial velocities of emission lines. Fluorescence processes in Fe II, Fe III, and Cr II are discussed, and the discovery of an ejected filament producing Sr II and [Sr II] emission is reported. Also, a list of 2000 emission line identifications is presented and discussed. The chemically peculiar star Chi Lupi was the target of the "Pathfinder Project", a mapping of the UV spectrum of the star using the GHRS. An investigation of the abundance and isotopic composition of boron in Chi Lupi is presented. The launch of space telescopes has put greater demands on the quality of atomic data needed for the analyses of the observed spectra. This thesis presents laboratory measurements of wavelengths and transitions isotope shifts in the B~II spectrum