2MASS J22560844+5954299: the newly discovered cataclysmic star with the deepest eclipse

Abstract

Context. The SW Sex stars are assumed to represent a distinguished stage in cataclysmic variable (CV) evolution, making it especially important to study them. Aims. We discovered a new cataclysmic star and carried out prolonged and precise photometric observations, as well as mediumresolution spectral observations. Modelling these data allowed us to determine the physical parameters and to establish its peculiarities. Methods. To obtain a light curve solution we used model whose emission sources are a white dwarf surrounded by an accretion disk with a hot spot, a gaseous stream near the disk's lateral side, and a secondary star filling its Roche lobe. The obtained physical parameters are compared with those of other SW Sex-subtype stars. Results. The newly discovered cataclysmic variable 2MASS J22560844+5954299 shows the deepest eclipse amongst the known nova-like stars. It was reproduced by totally covering a very luminous accretion disk by a red secondary component. The temperature distribution of the disk is flatter than that of steady-state disk. The target is unusual with the combination of a low mass ratio q ∼ 1.0 (considerably below the limit q = 1.2 of stable mass transfer of CVs) and an M-star secondary. The intensity of the observed three emission lines, Hα, He 5875, and He 6678, sharply increases around phase 0.0, accompanied by a Doppler jump to the shorter wavelength. The absence of eclipses of the emission lines and their single-peaked profiles means that they originate mainly in a vertically extended hot-spot halo. The emission Hα line reveals S-wave wavelength shifts with semi-amplitude of around 210 km s −1 and phase lag of 0.03. Conclusions. The non-steady-state emission of the luminous accretion disk of 2MASS J22560844+5954299 was attributed to the low viscosity of the disk matter caused by its unusually high temperature. The star shows all spectral properties of an SW Sex variable apart from the 0.5 central absorption.

Light curve solutions of six eclipsing binaries at the lower limit of periods for W UMa stars

“…But the period 0.24914 d of target 5 (see further Table 5) we obtained was around 11 % longer than the previous value (Table 1). This result is not so surprising because the follow-up observations of variable stars from different data bases sometimes reveal different periods than the previous values (Norton et al 2011;Mighell & Plavchan 2013;Lohr et al 2013;Kjurkchieva et al 2014;Mayangsari et al 2014). This is a consequence of the automated frequency analyses of the huge data sets.…”

Discovery of deep eclipses in the cataclysmic variable IPHAS J051814.33+294113.0

“…Their total number is 20. Among novalike variables, the deepest eclipse was observed in 2MASS J22560844+5954299, where the eclipse depth reaches 4.0-4.3 mag in B band (Kjurkchieva et al 2015). Among dwarf novae, the deepest eclipse was observed in AR Cnc, where the eclipse depth is a bit larger than 3 mag in B and V bands (Howell et al 1990).…”

Extraction of Mathematical Correlations Applied in the Aerodynamic Separation of Solid Particles

“…Many researchers apply multiple mathematical programs to identify specific connections between the parameters analyzed, thanks to scientific advancements in hardware and software technology. This is why, regardless of the domain to which it refers, e.g., industry, agriculture, medicine, the environment, and so on, mathematical modeling has progressed [1][2][3][4][5][6][7][8]. As a result, in addition to traditional equations, such as those used in physics to explain specific events, many scientific articles have recently appeared in the literature that present mathematical correlations connecting the parameters under study.…”