Spectroscopic determinations of surface gravities of giant stars, and ultraviolet observations of RR Lyrae and X Arietis

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6935232

Bonnell, J T

The surface gravities of four K giant stars, including the well-known standard stars Arcturus (..cap alpha.. Boo) and Aldebaran (..cap alpha.. Tau) were determined from an analysis of the molecular dissociation equilibrium of OH. High-resolution FTS spectra of the infrared ground-state vibration-rotation lines of the OH ..delta..v = 1 and ..delta.. v = 2 sequences were used in the analysis. The oxygen abundances were derived from the (O I) lines at 6300 and 6363 A. The surface gravities of 5 further G and K giants were determined from an analysis of the molecular equilibrium of MgH, the magnesium abundances being derived from visible and near-infrared high-excitation-potential MgI lines. Ultraviolet observations of RR Lyrae and X Arietis obtained with the Astronomical Netherlands Satellite (ANS) and the International Ultraviolet Explorer (IUE) satellite are also discussed. These observations are compared with light curves derived using model atmospheres and synthetic spectrum calculations in conjunction with angular diameters determined by Manduca et al. (1981) from photometry at longer wavelengths. A good agreement is found.

• Research Organization: Maryland Univ., College Park (USA)
• OSTI ID: 6935232
• 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
DISSOCIATION
GIANT STARS
GRAVITATION
HYDROXYL RADICALS
RADICALS
SPECTRA
STARS
SURFACE PROPERTIES
ULTRAVIOLET SPECTRA