Query : 2003A&A...410..239S

2003A&A...410..239S - Astronomy and Astrophysics, volume 410, 239-252 (2003/10-4)

Delays in dwarf novae. I: The case of SS Cygni.


Abstract (from CDS):

Using the disc instability model and a simple but physically reasonable model for the X-ray, extreme UV, UV and optical emission of dwarf novae we investigate the time lags observed between the rise to outburst at different wavelengths. We find that for ``normal'', i.e. fast-rise outbursts, there is good agreement between the model and observations provided that the disc is truncated at a few white dwarf radii in quiescence, and that the viscosity parameter α is ∼0.02 in quiescence and ∼0.1 in outburst. In particular, the increased X-ray flux between the optical and EUV rise and at the end of an outburst, is a natural outcome of the model. We cannot explain, however, the EUV delay observed in anomalous outbursts because the disc instability model in its standard α-prescription form is unable to produce such outbursts. We also find that the UV delay is, contrary to common belief, slightly longer for inside-out than for outside-in outbursts, and that it is not a good indicator of the outburst type.

Abstract Copyright:

Journal keyword(s): accretion, accretion discs - instabilities - stars: individual: SS Cygni - stars: novae, cataclysmic variables - stars: binaries : close

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 V* HT Cas CV* 01 10 13.1213394144 +60 04 35.489642700     14.10     M5.5e 384 0
2 V* SS Cyg CV* 21 42 42.8034497592 +43 35 09.867842484 11.07 12.651 12.032 9.326   K5V 1280 1

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