SIMBAD references

2004AJ....128.2988S - Astron. J., 128, 2988-2996 (2004/December-0)

The spectra of type II cepheids. III. The Hα line and helium emission in long-period stars.

SCHMIDT E.G., JOHNSTON D., LEE K.M., LANGAN S., NEWMAN P.R. and SNEDDEN S.A.

Abstract (from CDS):

We have obtained Hα profiles from 175 spectra of 37 Cepheids with periods longer than 8 days. About two-thirds of the stars are likely type II Cepheids. In contrast to the situation among short-period stars, the velocity of Hα relative to the metal-line spectrum is not a useful parameter for distinguishing type I and type II Cepheids. On the other hand, at periods longer than 11 days and shorter than 34 days strong emission is observed in many stars and appears to be a good discriminator of type. On this basis we identify one probable type I Cepheid at a large distance from the Galactic plane. We have found He λ5876 emission in seven Cepheids among the long-period stars discussed here and in one star with a short period, bringing to nine the number of type II Cepheids known to exhibit He emission.

Abstract Copyright:

Journal keyword(s): Stars: Variables: Cepheids - Stars: Population II

Status at CDS:  

Simbad objects: 38

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2020.04.10-21:02:42

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