Three radial modes and evolutionary state of AC Andromedae

Journal Article · Sun Feb 01 04:00:00 EST 1976 · Astrophys. J., v. 203, no. 3, pp. 616-624

OSTI ID:4043564

Fitch, W S; Szeidl, B

Analysis of 4662 yellow magnitudes measures, obtained at the Konkoly Observatory on 78 nights in 1958--1962, shows that AC And has its fundamental and first and second overtone radial pulsation modes (periods P$sub 0$=0/sup d/./sub /71124243, P$sub 1$=0/sup d/./sub /52512677, and P$sub 2$ =0/sup d/./sub / 421069) all excited and nonlinearly coupled. Fitting formulae, derived from published pulsation calculations for high-metal-content models (Z=0.044), are given for the direct calculation of mass and radius from observed radial model period pairs. The multimode excitation of 25 Cepheid-strip stars (comprising eight Cepheids, one RR Lyrae star, nine RRs stars, and seven delta Scuti stars) is discussed. AC And is found to have a mass Mapprox. =3.1 M/sub sun/ and to be a high-mass analog of the delta Scuti stars, in the hydrogen-shell-burning and helium-core-contraction stage of evolution. Pulsation theory, evolution theory, and observation seem to be in excellent agreement for AC And and delta Sct. (AIP)

• Research Organization: Steward Observatory, University of Arizona
• NSA Number: NSA-33-030628
• OSTI ID: 4043564
• Journal Information: Astrophys. J., v. 203, no. 3, pp. 616-624, Journal Name: Astrophys. J., v. 203, no. 3, pp. 616-624; ISSN ASJOA
• Country of Publication: United States
• Language: English

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