The structure of the Cepheid instability strip

Journal Article · Tue May 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168689· OSTI ID:6711957

Fernie, J D ^[1]

---

1. David Dunlap Observatory, Richmond Hill (Canada)

About 100 classical Cepheids having color excesses on a homogeneous system with standard errors of 0.02 or less mag are used with the Feast-Walker period-luminosity-color relation to study the distribution of such stars in the instability strip. It is found that mean (B-V)mag is a better indicator of mean effective temperature than is mean B(i) - mean V(i)(i). The blue edge of the color-magnitude distribution is consistent with the theoretical blue edge for Y = 0.28 and Z = 0.02. Although the highest amplitude stars are found near the center of the period-color array, high- and low-amplitude stars can intermingle, and both kinds are to be found near the edges of the distribution. The same is true on the C-M array. Finally, it is pointed out that the Cepheids do not populate the instability strip uniformly if the red edge is taken to be parallel to the theoretical blue edge. Rather, the local instability region runs as a parallelogram in the C-M array from the theoretical blue edge upward and to the red. 24 refs.

• OSTI ID: 6711957
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 354; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CEPHEIDS
COLOR
DIAGRAMS
ERRORS
HERTZSPRUNG-RUSSELL DIAGRAM
LUMINOSITY
OPTICAL PROPERTIES
ORGANOLEPTIC PROPERTIES
PHYSICAL PROPERTIES
PULSATING VARIABLE STARS
STAR EVOLUTION
STARS
VARIABLE STARS