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The binary nature of the Ap star 53 Cam
Author(s) -
Scholz G.
Publication year - 1978
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.19782990604
Subject(s) - physics , astrophysics , rotation period , radial velocity , orbit (dynamics) , ionization , spurious relationship , binary number , binary star , magnetic field , rotation (mathematics) , star (game theory) , period (music) , geodesy , stars , ion , geometry , mathematics , geology , arithmetic , quantum mechanics , engineering , aerospace engineering , statistics , acoustics
The radial velocities of the Ap star 53 Cam = HD 65339 show a longtime variation corresponding to a binary motion. For the elements of the binary system the following values were derived: K = 8km/s, γ = ‐2.2 km/s, P = 2380 days. e = 0.56, ω = 10°, and a · sin i = 22 · 10 7 km. A second period of about 1850 days is indicated but this value seems to be a spurious period. Investigations of Z EEMAN spectrograms made by several authors gave a magnetic period of a bout 8 days. This period, interpreted as rotational period of the star, obviously differs a little for various observational times depending on the position in the binary orbit; so that the period is smaller at the time of the apastron passage. At present it is not possible to decide wheter this behaviour – if real – preponderantly reflects changes of the velocity of rotation or of the magnetic field. Furthermore the radial velocities show a dependence on the state of ionization of the elements in such a way that evidently lines from neutral elements have larger radial velocities (absolute values) than those of the ionized elements. These differences also depend on the position in the binary orbit as mentioned for the magnetic periods.