RX J0515.6+0105: an AM HER System with an 8 Hour Period?
Abstract
We report multiwavelength observations of the optical counterpart of the ROSAT X-ray source RX J0515.6+0105. Optical photometric data spanning ~ 1 yr reveal eclipse features that are deep, total, and variable in profile. The eclipse timings give an orbital ephemeris of JD_⊙ = 2449087.8173(3) + 0.3326120(7) E, with considerable phase jitter caused by the variable eclipse profiles. The system is characterized by a soft thermal spectrum (kTbb =~ 33 eV), strong He II lambda 4686 emission, large-amplitude radial velocity variations consistent with emission from an accretion stream, and, most significantly, significant circular polarization. The optical light curve is characterized by a strong and asymmetric brightness modulation at twice the orbital frequency, and by quasi-periodic oscillations with a characteristic time scale of 6 -- 15 min. Spectroscopic observations suggest the possibility of cyclotron features near 8500 Angstroms and 5900 Angstroms. These wavelengths are roughly consistent with those expected for the second and third harmonics of cyclotron radiation originating from an ~ 61 MG field. Taken together, these characteristics strongly suggest that RX J0515.6+0105 is a magnetic cataclysmic variable, most likely an AM Herculis system in which the accretion column/stream is eclipsed. However, the possibility that the white dwarf rotates asynchronously, and that RX J0515.6+0105 is a DQ Her system, has not yet been ruled out unequivocally.
- Publication:
-
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1994
- Bibcode:
- 1994AAS...18511604S