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Photometric observations of V4633 Sgr (Nova Sagittarii 1998) during 1998-2005 reveal the presence of a stable photometric periodicity at P1=180.8 min which is probably the orbital period of the underlying binary system. A second period was present in the light curve of the object for six years. Shortly after the nova eruption it was measured as P2=185.6 min. It has decreased monotonically in the following few years reaching the value P2=183.9 min in 2003. In 2004 it was no longer detectable. We suggest that the second periodicity is the spin of the magnetic white dwarf of this system that rotates nearly synchronously with the orbital revolution. According to our interpretation, the post-eruption evolution of Nova V4633 Sgr follows a track similar to the one taken by V1500 Cyg (Nova Cygni 1975) after that nova eruption, on a somewhat longer time scale. The asynchronism is probably the result of the nova outburst that lead to a considerable expansion of the white dwarfs photosphere. The increase in the moment of inertia of the star was associated with a corresponding decrease in its spin rate. Our observations have followed the spinning up of the white dwarf resulting from the contraction of its outer envelope as the star is slowly retuning to its pre-outburst state. It is thus the second known asynchronous polar classical nova.
We report the results of observations of V4633 Sgr (Nova Sagittarii 1998) during 1998-2000. Two photometric periodicities were present in the light curve during the three years of observations: a stable one at P=3.014 h, which is probably the orbital
We report the new detection of $^7$Be II in the ultraviolet spectra of V5669 Sgr during its early decline phase ($+24$ and $+28$ d). We identified three blue-shifted absorption systems in our spectra. The first two, referred to as low- and high-veloc
A review of the present status of nova modeling is made, with a special emphasis on some specific aspects. What are the main nucleosynthetic products of the explosion and how do they depend on the white dwarf properties (e.g. mass, chemical compositi
We are currently involved in a multifaceted campaign to study extragalactic classical novae in the Local Group and beyond. Here we report on-going results from the exploitation of the POINT-AGAPE M31 dataset; initial results from our Local Group imag
CD Ind is one of only four confirmed asynchronous polars (APs). APs are strongly magnetic cataclysmic variables of the AM Herculis subclass with the characteristic that their white dwarfs rotate a few per cent out of synchronism with their binary orb