Title: First results from the Goddard High-Resolution Spectrograph - Evidence for photospheric microturbulence in early O stars - Are surface gravities systematically underestimated?
Abstract:view Abstract Citations (33) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS First Results from the Goddard High-Resolution Spectrograph: Evidence for ...view Abstract Citations (33) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS First Results from the Goddard High-Resolution Spectrograph: Evidence for Photospheric Microturbulence in Early O Stars: Are Surface Gravities Systematically Underestimated? Hubeny, I. ; Heap, S. R. ; Altner, B. Abstract GHRS spectra of two very hot stars provide evidence for the presence of microturbulence in their photospheres. In attempting to reproduce the observed spectra, theoretical models have been built in which the microturbulence is allowed to modify not only the Doppler line widths (classical 'spectroscopic' microturbulence), but also the turbulent pressure (thus mimicking a 'physical' turbulence). It is found that a corresponding modification of the temperature-pressure stratification influences the hydrogen and helium line profiles to the extent that the surface gravities of early O stars determined without considering microturbulence are too low by 0.1-0.15 dex. Thus, including microturbulence would reduce, or resolve completely, a long-standing discrepancy between evolutionary and spectroscopic stellar masses. Publication: The Astrophysical Journal Pub Date: August 1991 DOI: 10.1086/186110 Bibcode: 1991ApJ...377L..33H Keywords: Early Stars; O Stars; Spectrographs; Stellar Gravitation; Stellar Spectra; Turbulence; Ultraviolet Spectra; High Resolution; Hubble Space Telescope; Photosphere; Stellar Atmospheres; Stellar Winds; Subdwarf Stars; Astrophysics; STARS: EARLY-TYPE; STARS: INDIVIDUAL NAME: MELNICK 42; STARS: INDIVIDUAL ALPHANUMERIC: BD; 75 DEGREES 325; STARS: MASSIVE; STARS: SUBDWARFS; STARS: WINDS; TURBULENCE; ULTRAVIOLET: SPECTRA full text sources ADS | data products SIMBAD (2) MAST (2) ESA (1)Read More
Publication Year: 1991
Publication Date: 1991-08-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 17
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