1981/10/01 by M. Breger · 2 citations
Physics and Astronomy · #Stellar, planetary, and galactic studies #Astronomy and Astrophysical Research #Astro and Planetary Science
paper · doi:10.1086/159327
openalex publication_date 1981/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/04/04
HR 7308 is a classical Cepheid with the shortest known period. Photoelectric observations taken during 1966-1969 are presented and combined with recent work. The primary period of oscillation is found to be 1.49077 + or - 0.00001d, somewhat shorter than the previously published period. The amplitude of HR 7308 varies by over a factor of 5 with a period of about 1210d. An alternate period of 955d cannot be excluded due to the 1970-1977 gap in observations. Except for the variable amplitude, no secondary periods can be found in the data. The 0.71 period ratio, commonly found in short-period Cepheids, is absent. Various models utilizing two close periods have been used (leading to amplitude variations and phase jitter of the primary oscillation) as well as models of variable amplitudes superposed on a constant oscillation.