Stellar model chromospheres. VIII. 70 Ophiuchi A (K0 V) and epsilon Eridani (K2 V)
Journal Article
·
· Astrophys. J.; (United States)
High resolution Ca II K line profiles and Mg II h and k line fluxes are used to derive photosphere and chromosphere models of two K dwarf active chromosphere stars, epsilon Eri and 70 Oph A. These models are computed on the basis of partial redistribution diagnostics. The derived values of T/sub min//T/sub eff/ and m/sub o/ (the mass column density at the top of the chromosphere) confirm and extend the T/sub min//T/sub eff/ versus T/sub eff/ and the log m/sub 0/ versus log g relations previously found in Paper VII. In particular, we find that T/sub min//T/sub eff/ is significantly larger in epsilon Eri and 70 Oph A than in ..cap alpha.. Cen B, presumably due to enhanced metal abundance and resultant larger CO line blanketing in ..cap alpha.. Cen B. The main-sequence models thus far derived strongly suggest that chromospheric activity correlates with the lower chromospheric temperature gradient rather than the value of m/sub 0/.
- Research Organization:
- Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards
- OSTI ID:
- 6684696
- Journal Information:
- Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 222:3; ISSN ASJOA
- Country of Publication:
- United States
- Language:
- English
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