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A Study of the Rapidly Rotating Variable Star HD 36705 (AB Doradus)

Published online by Cambridge University Press:  25 April 2016

J. L. Innis
Affiliation:
Department of Physics, Monash University, Clayton, Victoria, 3168
R. D. Robinson
Affiliation:
Department of Physics, Monash University, Clayton, Victoria, 3168
D. W. Coates
Affiliation:
Department of Physics, Monash University, Clayton, Victoria, 3168
K. Thompson
Affiliation:
Department of Physics, Monash University, Clayton, Victoria, 3168

Abstract

Photoelectric B and V light curves and high dispersion spectroscopic observations were obtained in 1985 February for the rapidly rotating spotted star HD 36705. The visual light range was about 0.09 magnitude, with a well correlated B-V change of approximately 0.04 magnitude, the star being redder when faintest. There is evidence for a broadband flare of ~0.05 magnitude in V and 0.07 magnitude in B. This occurred near maximum light.

Spectroscopic observations show a variation in the equivalent width of the Ca K emission by a factor of about two in antiphase with the photometric variations, maximum emission corresponding to minimum brightness. This is probably due to bright plages and enhanced chromospheric heating associated with the photospheric starspots.

High dispersion, high signal-to-noise spectroscopic observations confirm the presence of lithium λ 6708 as reported by Rucinski (1982, 1985).

Several interpretations of the nature of HD 36705 are discussed; however at present none is completely satisfactory and further observations are required. As the star is probably at less than 100 pc, a parallax determination may be possible, and could help answer many of the questions concerning HD 36705.

Type
Contributions
Copyright
Copyright © Astronomical Society of Australia 1985

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