Optical and Near-Infrared Photometric Observation during the Superoutburst of the WZ Sge-Type Dwarf Nova, V455 Andromedae - Astrophysics > Solar and Stellar AstrophysicsReport as inadecuate




Optical and Near-Infrared Photometric Observation during the Superoutburst of the WZ Sge-Type Dwarf Nova, V455 Andromedae - Astrophysics > Solar and Stellar Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We report on optical and infrared photometric observations of a WZ Sge-typedwarf nova, V455 And during a superoutburst in 2007. These observations wereperformed with the KANATA V, J, and K s bands and MITSuME g-, Rc, and Icbands telescopes. Our 6-band simultaneous observations allowed us toinvestigate the temporal variation of the temperature and the size of theemitting region associated with the superoutburst and short-term modulations,such as early and ordinary superhumps. A hot >11000 K accretion disk suddenlydisappeared when the superoutburst finished, while blackbody emission, probablyfrom the disk, still remained dominant in the optical region with a moderatelyhigh temperature ~8000 K. This indicates that a substantial amount of gas wasstored in the disk even after the outburst. This remnant matter may be a signof an expected mass-reservoir which can trigger echo outbursts observed inseveral WZ Sge stars. The color variation associated with superhumps indicatesthat viscous heating in a superhump source stopped on the way to the superhumpmaximum, and a subsequent expansion of a low-temperature region made themaximum. The color variation of early superhumps was totally different fromthat of superhumps: the object was bluest at the early superhump minimum. Thetemperature of the early superhump light source was lower than that of anunderlying component, indicating that the early superhump light source was avertically expanded low-temperature region at the outermost part of the disk.



Author: R. Matsui, M. Uemura, A. Arai, M. Sasada, T. Ohsugi, T. Yamashita, K. S. Kawabata, Y. Fukazawa, T. Mizuno, H. Katagiri, H. Takaha

Source: https://arxiv.org/







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