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The Light Curve of the Pulsating Extreme Helium Star BD +13°3224: Further Evidence of a Decline in the Period Decrease Rate

Published online by Cambridge University Press:  12 April 2016

A.E. Lynas-Gray  and
D. Kilkenny
A.E. Lynas-Gray
Affiliation:
Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, England.
D. Kilkenny
Affiliation:
South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 Cape Town, South Africa.

Abstract

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Further optical and infrared (J-filter) observations are presented for the extreme helium star BD +13°3224. No infrared excess, which could have been attributed to a cool companion, is found. Very recent times of maximum light confirm the ephemeris cubic term already proposed. Current models for the evolution of BD +13°3224, while approximately accounting for the period decrease rate (Ṗ), do not explain the decreasing Ṗ indicated by the cubic term.

Type
III Hot Extreme Helium Stars
Information
International Astronomical Union Colloquium , Volume 87: Hydrogen Deficient Stars and Related Objects , 1985 , pp. 117 - 123
Copyright
Copyright © Reidel 1986

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