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EUVE Observations of BY Dra Systems

Published online by Cambridge University Press:  12 April 2016

R.A. Stern  and
J.J. Drake
R.A. Stern
Affiliation:
Solar and Astrophysics Laboratory, Lockheed Martin Palo Alto Research Lab, O/91-30 Bldg 252, 3251 Hanover Street, Palo Alto, CA, 94304, USA Center for EUV Astrophysics
J.J. Drake
Affiliation:
Center for EUV Astrophysics, 2150 Kittredge Street, University of California, Berkeley, CA 94720-5030, USA

Abstract

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We have observed 3 nearby BY Dra systems, FK Aqr, BF Lyn, and DH Leo, with the EUVE spectrometers. All 3 show evidence of high-temperature (~ 107 K) plasma; FK Aqr and DH Leo show significant variability in their Deep Survey lightcurves. In FK Aqr, spectral differences between its “quiescent” and “active” states suggest possible differences in the plasma density. In DH Leo, the Deep Survey lightcurve, taken over nearly 8 days, shows a distinct period of ~ 1.05 days, consistent with the photometric period. The emission measure distributions of all three systems are rather similar in shape, and can be well-represented by a power law with slope ~ 1.5 from 6.2–7.0 in log T.

Type
III. Coronae of Cool Stars
Information
International Astronomical Union Colloquium , Volume 152: Astrophysics in the Extreme Ultraviolet , 1996 , pp. 135 - 140
Copyright
Copyright © Kluwer 1996

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