Study of period changes for 38 RR Lyrae variables in the globular cluster M15

Abstract

view Abstract Citations (28) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Study of period changes for 38 RR Lyrae variables in the globular cluster M15. Smith, H. A. ; Sandage, A. Abstract Of the 38 M15 RR Lyrae stars investigated, 19 have probably undergone period changes between 1896 and 1978 of both abrupt and gradual character. Five times as many stars are believed to have increased in period as decreased, and period changes show no correlation with position in the color-magnitude diagram, contrary to evolutionary expectation. The ab-types variables tend to have larger changes than the c types, but the difference in the mean rate of period change for a band c-type variables is found to be too small to be significant. It is suggested that observations of the M15 variables over the next century may clarify the possibility of evolutionary period change detection, despite short-period noise due to erratic changes in the stellar radius. Publication: The Astronomical Journal Pub Date: December 1981 DOI: 10.1086/113066 Bibcode: 1981AJ.....86.1870S Keywords: Cepheid Variables; Globular Clusters; Periodic Variations; Star Clusters; Stellar Evolution; Color-Magnitude Diagram; Hertzsprung-Russell Diagram; Stellar Luminosity; Stellar Oscillations; Astronomy; Globular Clusters:RR Lyrae Stars; Period Changes:RR Lyrae Stars; Pulsations:RR Lyrae Stars full text sources ADS | data products SIMBAD (39)