The He I D3 5876 A line as an activity and structural indicator in F-type Hyades stars

Bibcode
1990Ap&SS.169...67G
DOI
10.1007/BF00640688
Garcia Lopez, R. J.; Rebolo, R.; Beckman, J. E.; McKeith, C. D.
Bibliographical reference

(IAU, European Regional Astronomy Meeting on New Windows to the Universe, 11th, La Laguna, Spain, July 3-8, 1989) Astrophysics and Space Science (ISSN 0004-640X), vol. 169, no. 1-2, July 1990, p. 67-75.

Advertised on:
7
1990
Number of authors
4
IAC number of authors
0
Citations
0
Refereed citations
0
Description
The first results of a study of F-type MS stars using the He I D3 absorption feature at 5876 A as an indicator of stellar activity and structure are presented. The observations were obtained with the QUB echelle spectrograph at the Cassegrain focus of the 4.2 m William Herschel telescope. Seventeen F-stars of the Hyades main sequency were chosen as a first sample. It was found that He I D3 and X-ray emission appear around B - V = 0.3, indicating the onset of sub-surface convection zones. Below this value, in stars with B - V not greater than 0.42-0.44 the behavior of the He I D3 equivalent width against Rossby number is different from that observed in later type stars, indicating that the presence of nonradiative mechanisms other than dynamo must be important in heating the chromospheres of these hotter stars.
Type
Non-refereed
F stars
Main sequence stars
Stellar activity
Stellar atmospheres

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