The distribution of periods of the magnetic A-type stars

Abstract

view Abstract Citations (77) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The distribution of periods of the magnetic A-type stars. Wolff, S. C. Abstract Four-color (uvby) photoelectric observations are used to obtain periods for several Ap stars with v sin i less than 10 km/sec. The derived periods are 69.0 days for HD 5797, 10.61 days for HD 22374, 69 days for HT 3724, and 5.07 days for HD 115708. The magnetic field strengths measured from Zeeman spectrograms of 33 Lib vary with a period of 23.26 days. Photoelectric and Zeeman spectroscopic observations yield a period of 525 days for HD 2453. Evidence is given that suggests that HR 4816 may vary on a time scale of 10 years. The present observations, combined with results published previously, make it possible to derive the distribution of periods for the cool (non-Si) Ap-type stars. It is argued that the data support the hypothesis that the period of variation is to be identified in all cases with the period of rotation, and that the existence of Ap stars with extremely long periods is due to the loss of angular momentum through some form of magnetic braking. Publication: The Astrophysical Journal Pub Date: November 1975 DOI: 10.1086/153958 Bibcode: 1975ApJ...202..127W Keywords: A Stars; Magnetic Stars; Stellar Rotation; Ubv Spectra; Angular Momentum; Astronomical Models; Electrophotometers; Magnetic Effects; Magnetic Flux; Periodic Variations; Zeeman Effect; Astrophysics full text sources ADS | data products SIMBAD (35) GCPD (1)