The upper field-strength limit in AM Herculis systems
نویسندگان
چکیده
منابع مشابه
Magnetic field and unstable accretion during AM Herculis low states
A study of AM Her low states in September 1990 and 1991 and June-July 1997 is reported from a coordinated campaign with observations obtained at the Haute-Provence observatory, at the 6-m telescope of the Special Astrophysical Observatory and at the 2.6m and 1.25m telescopes of the Crimean observatory. Spectra obtained at different dates when the source was in low states at a comparable V magni...
متن کاملAm Herculis Binaries in the Rosat Era
The current census of AM Herculis binaries and AM Her candidates exceeds 50 systems of which 29 are ROSAT discoveries. The increased number provides a basis to study the more general properties of the class. We discuss the space density, observations relevant to the evolution of magnetic CVs, the statistics of magnetic eld measurements, and current ideas on the accretion scenarios.
متن کاملHST / GHRS observations of AM Herculis ⋆
We present phase-resolved spectroscopy of AM Herculis obtained with the HST/GHRS when the system was in a high state. The ultraviolet light curve shows a quasi-sinusoidal modulation, which can be explained by a hot spot on the rotating white dwarf. The broad Lyα absorption expected for photospheric radiation of a moderately hot white dwarf is largely filled in with emission. The UV/FUV spectrum...
متن کاملHigh and low states of the system AM Herculis
Context. We investigate the distribution of optically high and low states of the system AM Herculis (AM Her). Aims. We determine the state duty cycles, and their relationships with the mass transfer process and binary orbital evolution of the system. Methods. We make use of the photographic plate archive of the Harvard College Observatory between 1890 and 1953 and visual observations collected ...
متن کاملBeppoSAX observations of AM Herculis in intermediate and high states
Temporal and spectral analyses from BeppoSAX observations of AM Her performed during both an intermediate and a high state are presented and discussed. Optical observations taken a few days after the X–ray ones are also presented. During the intermediate state observation, the source was in its “normal”, one–pole accretion mode. In the high state it switched to an hitherto unobserved atypical ”...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1989
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/237.4.845