A new two-pole accretion polar: RX J1846.9+5538
Por:
Schwarz R., Greiner J., Tovmassian G.H., Zharikov S.V., Wenzel W.
Publicada:
1 ene 2002
Resumen:
We report the discovery of a new, bright (V ~ 17m) AM Her system as the optical counterpart of the soft ROSAT All-Sky-Survey source RXJ1846.9+5538 (=1RXS J184659.4+553834). Optical photometric and spectroscopic follow-up observations reveal a single of 128.7 min, consistent with a high degree of spin-orbit synchronization, and a low polar field strength (B < 20 MG) of the primary accretion region. The system was observed in optical intermediate and high states that differ by about 1 mag. These brightness variations were accompanied by a correlated change of the optical light curve, which we interpret as a switch between one- and two-pole accretion. This explanation is also supported by the X-ray light curves, which at two different epochs display emission from two equally bright accretion regions separated by ~ 160°. Both spots possess distinct spectral X-ray properties as seen from the X-ray hardness ratio, where the secondary accretion region appears significantly softer, thus probably indicating a higher field strength compared to the primary region. In all ROSAT pointings a deep dip is present during the primary flux maxima, very like caused by absorption in one of the accretion streams.
Filiaciones:
Schwarz R.:
Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
Greiner J.:
Astrophysical Institute Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße, 85740 Garching, Germany
Tovmassian G.H.:
Instituto de Astronomia, UNAM, Apdo.Post. 877, 22860 Ensenada, B.C., Mexico
Zharikov S.V.:
Instituto de Astronomia, UNAM, Apdo.Post. 877, 22860 Ensenada, B.C., Mexico
Wenzel W.:
Sonneberg Observatory, 96515 Sonneberg, Germany
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