127 research outputs found
The SW Sex-type star 2MASS J01074282+4845188: an unusual bright accretion disk with non-steady emission and a hot white dwarf
We present new photometric and spectral observations of the newly discovered
nova-like eclipsing star 2MASS J01074282+4845188. To obtain a light curve
solution we used model of a nova-like star whose emission sources are a white
dwarf surrounded by an accretion disk, a secondary star filling its Roche lobe,
a hot spot and a hot line. 2MASS J01074282+4845188 shows the deepest permanent
eclipse among the known nova-like stars. It is reproduced by covering the very
bright accretion disk by the secondary component. The luminosity of the disk is
much bigger than that of the rest light sources. The determined high
temperature of the disk is typical for that observed during the outbursts of
CVs. The primary of 2MASS J01074282+4845188 is one of the hottest white dwarfs
in CVs. The temperature of 5090 K of its secondary is also quite high and more
appropriate for a long-period SW Sex star. It might be explained by the intense
heating from the hot white dwarf and the hot accretion disk of the target. The
high mass accretion rate \dot{M} = 8\times 10^{-9} M_{\sun} yr, the
broad and single-peaked H emission profile, and the presence of an
S-wave are sure signs for the SW Sex classification of 2MASS J01074282+4845188.
The obtained flat temperature distribution along the disk radius as well as the
deviation of the energy distribution from the black-body law are evidence of
the non-steady emission of the disk. The close values of the disk temperature
and the parameter of 2MASS J01074282+4845188 and those of the
cataclysmic stars at eruptions might be considered as an additional argument
for the permanent active state of nova-like stars.Comment: 11 pages, 11 figures, 5 tables. Accepted for publication in A&
Light Curve Solutions of Eclipsing Binaries in SMC
We propose a procedure for light-curve solution of eclipsing binary stars in
the Small Magellanic Cloud for which photometric data have been obtained in the
framework of the OGLE project as well as way of determination of the global
stellar parameters on the basis of the obtained solutions, some empirical
relations as well as the distance to the SMC. Several examples illustrate this
procedure.Comment: 10 pages, 2 figures, accepte
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