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The Abundances of Vega from the Ultraviolet Spectrum

Published online by Cambridge University Press:  12 April 2016

Fiorella Castelli
Fiorella Castelli*
Affiliation:
CNR-GNA c/o Osservatorio Astronomico Via G.B. Tiepolo 11 - 34131 Trieste -Italy

Abstract

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We derived preliminary abundances from the ultraviolet spectrum of Vega by comparing high-resolution Copernicus spectra with spectra computed with the ATLAS9 code and with updated line lists. The Teff=9400 K, log g=3.90 model, which fits the visual flux and the Balmer profiles is able to fit the ultraviolet flux either with [M/H]=−l and microturbulent velocity ξ= 2 km s−1 or with [M/H]=−0.5 and ξ=0 km s−1. The line spectrum is fitted by ξ=2 ± 0.5 km s−1 and by an iron abundance log (N(Fe)/Ntot)=−5.2 ±0.1 dex. All the observed elements indicate underabundances ranging from about −0.35 dex (C ) up to about −1 dex (Ni, Zn). The origin of the underabundances is an open question.

Type
II. Atmospheres, a window to the interior
Information
International Astronomical Union Colloquium , Volume 137: Inside the Stars , 1993 , pp. 202 - 204
Copyright
Copyright © Astronomical Society of the Pacific 1993

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