The 1051 S period of the interacting binary white dwarf AM CVn.
Abstract
The close binary system AM CVn consists of two white dwarfs; the lower mass white dwarf, a helium white dwarf, is transferring mass to its higher mass companion. The light curve of AM CVn has a double humped variation with a period of 1051 s that previously was identified with the orbital period of the system. An earlier measurement of the 1051 s period seemed to show that it was increasing too rapidly to be easily understood. Therefore, the rate of change of the 1051 s period has been remeasured. It is found that the period is changing two orders of magnitude more slowly than previously thought: dP/dt = (-3.2 + or - 0.6) 10 to the -12th s/s. Since the mass losing star in AM CVn is a white dwarf, the orbital period of the system must be increasing. It is found that the 1051 s period is decreasing, and therefore, cannot be caused by orbital motion. The 1051 s period is reinterpreted as the rotation period of the accreting white dwarf, which must then be magnetized. Also found is a 1011.4 s period in the light curve that may be related to the orbital period, but cannot itself be the orbital period. Finally, it is shown that the double humped light curve may really be a single humped light curve with a period of 525.5 s.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 1984
- Bibcode:
- 1984A&A...135....1S
- Keywords:
-
- Binary Stars;
- Light Curve;
- Stellar Motions;
- Stellar Spectrophotometry;
- Variable Stars;
- White Dwarf Stars;
- Magnetic Stars;
- Minima;
- Orbital Elements;
- Power Spectra;
- Stellar Mass Accretion;
- Stellar Rotation;
- Astronomy