Browsing by Subject "Novae"

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    Hubble Space Telescope and Optical Observations of Three Pulsating Accreting White Dwarfs in Cataclysmic Variables
    (2007) Szkody, Paula; Mukadam, Anjum; Gänsicke, Boris T; Woudt, Patrick A; Solheim, Jan‐Erik; Nitta, Atsuko; Sion, Edward M; Warner, Brian; Sahu, D K; Prabhu, T; Henden, Arne
    Ultraviolet observations using the Solar Blind Channel on the Hubble Space Telescope provide light curves and low-resolution spectra of three pulsating white dwarfs in the cataclysmic variables SDSS J013132.39-090122.3, SDSS J161033.64-010223.3, and SDSS J220553.98+115553.7. The UV light curves show enhanced pulsation amplitudes over those from simultaneous and previous optical photometry, while the UV-optical spectra are fit with white dwarf temperatures near 15,000 K. These temperatures place the accreting white dwarfs outside the instability zone for noninteracting DAV white dwarfs and show that the instability strip is complex for accreting white dwarfs
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    The effect of dust obscuration in RR Telescopii on optical and IR long-term photometryand Fe II emission lines
    (2006) Kotnik-Karuza, D; Friedjung, M; Whitelock, P A; Marang, F; Exter, K; Keenan, F P; Pollacco, D L
    Aims. Infrared and optical photometric and spectroscopic observations of the symbiotic nova RR Tel are used to study the effects and properties of dust in symbiotic binaries containing a cool Mira component, as well as showing obscuration events of increased absorption, which are typical for such Miras. Methods. A set of photometric observations of the symbiotic nova RR Tel in different wavelength bands - visual from 1949 to 2002 and near-infrared (JHKL) from 1975 to 2002 - are presented. The variability due to the normal Mira pulsation was removed from the JHKL data, which were then compared with the American Association of Variable Star Observers' (AAVSO) visual light curve. The changes of the Fell emission line fluxes during the 1996-2000 obscuration episode were studied in the optical spectra taken with the Anglo-Australian telescope. Results. We discuss the three periods during which the Mira component was heavily obscured by dust as observed in the different wavelength bands. A change in the correlations of J with other infrared magnitudes was observed with the colour becoming redder alter JD 2 446 600. Generally, J-K was comparable, while K-L was larger than typical values for single Miras. A distance estimate of 2.5 kpc, based on the IR data, is given. A larger flux decrease for the permitted than for the forbidden Fe II lines, during the obscuration episode studied, has been found. There is no evidence for other correlations with line properties, in particular with wavelength, which suggests obscuration due to separate optically thick clouds in the outer layers. Conclusions.