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Register a new userPhotometric study of an Eclipsing Binary in Praesepe
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Devarapalli Shanti Priya
Publication date
2013
fields
Physics
and research's language is
English
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We present CCD photometric observations of an eclipsing binary in the direction of the open cluster Praesepe using the 2 m telescope of IUCAA Girawali Observatory, India. Though the system was classified as an eclipsing binary by Pepper et al.(2008),detail investigations were lacking. The photometric solutions using the Wilson-Devinney code suggest that it is a W-type W UMa system and interestingly, the system parameters were similar to another contact binary system SW Lac.
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The new multi-color $BVRI$ photometric light curves of the short-period eclipsing binary GSC 3576-0170 were obtained on two consecutive nights (October 5 and 6, 2009). With the 2003 version of Wilson-Devinney program, the precise photometric solutions are derived for the first time. The result shows that GSC 3576-0170 is a semi-detached binary system with a large temperature difference of approximately 1490 K. The light-curve distortions are further explained by a hot spot on the secondary component through mass transfer via a stream hitting the facing surface of the secondary component. By analyzing all available light minimum times, we also derived an update ephemeris and found for the first time a possible periodic oscillation with an amplitude of 0.0038 days and a period of 4.3 years. The periodic oscillation could be explained either by the light-time effect due to a presumed third component or by magnetic activity cycle of the system.
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Double Periodic Variables (DPV) are among the new enigmas of semi-detached eclipsing binaries. These are intermediate-mass binaries characterized by a long photometric period lasting on average 33 times the orbital period. We present a spectroscopic and photometric study of the DPV V495 Cen based on new high-resolution spectra and the ASAS V-band light curve. We have determined an improved orbital period of $33.492 pm 0.002$ d and a long period of 1283 d. We find a cool evolved star of $M_{2}=0.91pm 0.2 M_{odot}$, $T_{2}= 6000pm 250 K$ and $R_{2}=19.3 pm 0.5 R_{odot}$ and a hot companion of $M_{1}= 5.76pm 0.3 M_{odot}$, $T_{1}=16960pm 400 K$ and $R=4.5pm0.2 R_{odot}$. The mid-type B dwarf is surrounded by a concave and geometrically thick disc, of radial extension $R_{d}= 40.2pm 1.3 R_{odot}$ contributing $sim$ 11 percent to the total luminosity of the system at the V band. The system is seen under inclination $84.!!^{circ}8$ $pm$ $0.!!^{circ}6$ and it is at a distance $d= 2092 pm 104.6$ pc. The light curve analysis suggests that the mass transfer stream impacts the external edge of the disc forming a hot region 11 % hotter than the surrounding disc material. The persistent $V<R$ asymmetry of the H$alpha$ emission suggests the presence of a wind and the detection of a secondary absorption component in He I lines indicates a possible wind origin in the hotspot region.
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