J/A+A/317/871 Revised spectral types of B-supergiants in the SMC (Lennon, 1997)
Revised spectral types for 64 B-supergiants in the Small Magellanic Cloud:
metallicity effects.
Lennon D.J.
<Astron. Astrophys., 317, 871-882 (1997)>
=1997A&A...317..871L 1997A&A...317..871L (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Stars, B-type ; Stars, supergiant ;
MK spectral classification
Keywords: stars: fundamental parameters - supergiants - Magellanic Clouds
Abstract:
The problem of the classification of metal poor stars, such as occur
in the Small Magellanic Cloud (SMC), is discussed with reference to
the applicability of the MK system in such an environment. An
alternative method is presented here and applied to B-type supergiants
in the SMC. A local reference system is first devised and then a
transformation to MK spectral types is determined by comparing the
trends of metal line strengths in these two systems. For the
determination of the luminosity class, we emphasize the need to use
the hydrogen Balmer line strengths independently of metal
line-strength considerations. This method is used to determine new
spectral types for 64 supergiants in the SMC, 75% of the sample
requiring classifications different from previous findings. These new
types result in much improved line strength - spectral type
correlations for He, C, N, O, Mg and Si. Corresponding changes in the
distribution of these stars in the Hertzsprung-Russell diagram of the
SMC reveal more clearly than before the existence of a ridge which may
be the SMC analogue of a similar feature found for the LMC by
Fitzpatrick & Garmany (1990ApJ...363..119F 1990ApJ...363..119F). The group of very
luminous supergiants lying above this ridge includes the LBV AV415
(R40), a property which this object has in common with LBVs in the
Large Magellanic Cloud. Also, for the first time, clear examples of
BN/BC supergiants are found in the SMC.
Description:
We tabulate the revised spectral types for 64 early-type supergiants as
listed in Table 2 of Lennon (1997A&A...317..871L 1997A&A...317..871L).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
sptypes.dat 16 64 Revised spectral types for 64 early-type
supergiants as listed in Table 2 of the paper
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Byte-by-byte Description of file: sptypes.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Simbad name of source
10- 16 A7 --- SpType Revised Spectral Type
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Acknowledgements:
Daniel J. Lennon, dlennon(at)iac.es
(End) Patricia Vannier [CDS] 12-Apr-2021