Studies of hot white dwarfs and instrumentation for stellar extreme ultraviolet astronomy

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5253842

Finley, D S

The opening up of the field of extreme ultraviolet (EUV) astronomy by forthcoming sky surveys promises to make possible many significant advances in our understanding of hot white dwarfs and of the physical processes which determine their observational properties. The EUV measurements, used in conjunction with observations in other wavelength ranges, will give accurate effective temperatures, helium abundances and interstellar hydrogen columns for significant numbers of hot white dwarfs. Perhaps half of the white dwarfs which will be discovered are currently hidden in multiple star systems. Study of these multiple stars will result in many more direct mass determinations of white dwarfs. Optimum utilization of the EUV survey day will be achieved by complementing the EUV observations with observations in other wavelength ranges. The efficacy of far ultraviolet (FUV) continuum measurements was evaluated by taking FUV spectra of several hot DA white dwarfs with the International Ultraviolet Explorer (IUE) satellite. These spectra were analyzed by means of our white dwarf model atmosphere code. In the course of this effort, accurate effective temperatures were obtained for the target stars, the IUE sensitivity was calibrated more accurately, and the visible photometry temperature scale for white dwarfs was revised. The feasibility of making successful space-based observations of white dwarfs and other stellar sources was demonstrated by building a satellite-borne telescope which will perform a photometric partial sky survey in a portion of the EUV band, between 80 and 300 {angstrom}. Further instrumental advances were made in the fabrication of the flight mirrors for the Extreme Ultraviolet Explorer experiment.

• Research Organization: California Univ., Berkeley, CA (USA)
• OSTI ID: 5253842
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASTRONOMY
DWARF STARS
ELECTROMAGNETIC RADIATION
EXTREME ULTRAVIOLET RADIATION
FABRICATION
IDENTIFICATION SYSTEMS
MASS
MEASURING INSTRUMENTS
MIRRORS
OPTIMIZATION
RADIATIONS
STARS
TELESCOPES
ULTRAVIOLET RADIATION
WHITE DWARF STARS