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The CA II triplet lines as diagnostics of luminosity, metallicity and chromospheric activity in cool stars

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dc.contributor.author Mallik, S. G. V
dc.date.accessioned 2008-08-22T10:17:43Z
dc.date.available 2008-08-22T10:17:43Z
dc.date.issued 1997-08
dc.identifier.citation Astronomy and Astrophysics Supplement Series, Vol. 124, No. 2, pp. 359 - 384 en
dc.identifier.issn 0365-0138
dc.identifier.uri http://hdl.handle.net/2248/3245
dc.description.abstract CCD spectra of the infrared triplet lines of ionized calcium at 8498, 8542, 8662 have been obtained at a spectral resolution of 0.4 Å in 146 stars brighter than V = +7.0 spanning a range in spectral types from F7 to M4 of all luminosity classes and a range in metallicity [Fe/H] from -3.0 to +1.1. These have been analysed to investigate the dependence of the Ca II triplet strengths on stellar parameters like luminosity, temperature and metallicity. A detailed study reveals a strong dependence on luminosity, much stronger for metal rich stars than for the metal poor ones and a milder dependence on metallicity, although much more conspicuous in supergiants than in dwarfs. All these correlations are found to be non-linear over the parameter space covered. The present study also shows chromospheric activity to be an important phenomenon affecting the strength and the shape of the line profiles. Stars of similar luminosity and metallicity have varying Ca II line depths owing to varying chromospheric emission filling in their Ca II absorption. The Ca II triplet strength is thus observed to be a triparametric discriminant in cool stars. en
dc.format.extent 625685 bytes
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher European Southern Observatory en
dc.relation.uri http://dx.doi.org/10.1051/aas:1997199 en
dc.subject Stars: Late-Type en
dc.subject Stars: Chromospheres en
dc.subject Galaxies: Stellar Content en
dc.title The CA II triplet lines as diagnostics of luminosity, metallicity and chromospheric activity in cool stars en
dc.type Article en

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