J/A+AS/124/359 Ca II triplet lines in cool stars (Mallik 1997)
The Ca II triplet lines as diagnostics of luminosity, metallicity and
chromospheric activity in cool stars
Mallik S.V.
<Astron. Astrophys. Suppl. Ser. 124, 359 (1997)>
=1997A&AS..124..359M 1997A&AS..124..359M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, late-type ; Stars, atmospheres ; Equivalent widths ;
Spectroscopy
Keywords: stars: late-type - stars: chromospheres - galaxies: stellar content
Abstract:
CCD spectra of the infrared triplet lines of ionized calcium at
λλ8498, 8542, 8662 have been obtained at a spectral
resolution of 0.4Å 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.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1 67 146 Stellar parameters
table2 54 146 Measured line strengths of the Ca II triplet
tables.tex 87 381 TeX version of the tables
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Byte-by-byte Description of file: table1
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number, Cat. III/135
8- 11 I4 --- HR ? HR number, Cat. V/50
13- 27 A15 --- Name Star name
28- 32 F5.2 mag Vmag V magnitude
34- 43 A10 --- SpType Spectral type
45- 48 F4.2 K Teff ? Effective temperature
50- 53 F4.2 mag R-I ? R-I color index
55- 59 F5.2 [cm/s2] logg ? Gravity surface
60 A1 --- n_logg [*] Note on logg (1)
63- 67 F5.2 [Sun] [Fe/H] ? Metallicity
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Note (1): * denotes the stars for which log g was estimated from their stellar
data using the procedure described in the text of the paper on p.6
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Byte-by-byte Description of file: table2
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD HD number, Cat. III/135
8- 11 I4 --- HR ? HR number, Cat. V/50
13- 26 A14 --- Name Star name
29- 32 F4.2 0.1nm EW8498 Equivalent width at lambda8498
34- 37 F4.2 0.1nm EW8542 Equivalent width at lambda8542
39- 42 F4.2 0.1nm EW8662 Equivalent width at lambda8662
44- 48 F5.2 0.1nm EWall Sum of EWs of all the three lines
50- 54 F5.2 0.1nm EW8542+EW8662 Sum of EWs of lambda8542 and lambda8662
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Acknowledgements: Sushma Mallik
(End) Patricia Bauer [CDS] 22-Nov-1996