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Analysis of the Helium Strong Star HD 37017

Published online by Cambridge University Press:  12 April 2016

Andrew P. Odell
Andrew P. Odell*
Affiliation:
Institute for Astronomy , University of ViennaTuerkenschanzstrasse 17 A-1180 Vienna, Austria

Abstract

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High resolution and signal-to-noise spectra (0.22 A; S/N ≥ 50) of the H-alpha and He I 6678 A lines have been obtained over most of the cycle of the intermediate helium strong star HD 37017 with the Coude spectrograph and CCD camera at KPNO. These spectra are modeled with the non-LTE code of Mihalas to derive properties of the star. Both of the observed lines show small equivalent width variations on the previously known timescale of 0.901 days. The profiles can be simulated by a model with temperature 20,000K, log g=3.4, and helium number fraction 0.25, and which has a helium-rich spot of radius 40° and helium number fraction of 0.60 on the equator. Other possible models are discussed, as well as a model of the weak emission on the wings of H-alpha.

Type
VI Intermediate Helium Stars
Information
International Astronomical Union Colloquium , Volume 87: Hydrogen Deficient Stars and Related Objects , 1985 , pp. 301 - 308
Copyright
Copyright © Reidel 1986

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