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تسجيل مستخدم جديدCyclic brightening in the short-period WZ Sge-type cataclysmic variable SDSS J080434.20+510349.2
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تأليف
S.V. Zharikov
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We have observed a new cataclysmic variable (CV) SDSS J080434.20+510349.2 and study the origin of a long-term variability found in its light curve. Multi-longitude time-resolved photometric observations were carried out to analyze the uncommon behavior also found recently in two newly discovered CVs. This study of SDSS J080434.20+510349.2 mainly concerns the understanding of the nature of the observed double-humped light curve and its relation to a cyclic brightening occurring during quiescence. The observations were obtained early in 2007, when the object was at about V~17.1, 0.4 mag brighter than the pre-outburst magnitude. The light curve shows a sinusoidal variability with an amplitude of about 0.07 mag and a periodicity of 42.48 min, which is half of the orbital period of the system. In addition, we have observed two mini-outbursts of the system up to 0.6 mag, with a duration of about 4 days each. The mini-outburst had a symmetric profile and repeated in about 32 days. Subsequent monitoring of the system shows a cyclical behaviour of such mini-outbursts with a similar recurrence period. The origin of the double-humped light curve and the periodic brightening is discussed in the light of the evolutionary state of SDSS J080434.20+510349.2.
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We present the results of photometric observations of SDSS J080434.20+510349.2 in its low state and during an outburst and spectroscopy during the outburst. We found such peculiarities as a long-term outburst with amplitude probably not less than 6m,
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Z Sge is decreasing at a rate of $dot{P}=-2.72(pm0.23)times{10^{-13}},s s^{-1}$. This secular decrease, coupled with previous detection of its donor, suggest that WZ Sge is a pre-bounce system. Further analysis indicates that the observed period decrease rate is about $1.53$ times higher than pure gravitational radiation (GR) driving. We constructed the evolutionary track of WZ Sge, which predicts that $P_{min}$ of WZ Sge is $sim77.98 (pm0.90)$ min. If the orbital period decreases at the current rate, WZ Sge will evolve past its $P_{min}$ after $sim25.3$ Myr. Based on the period evolution equation we find $dot{M}_{2}simeq4.04(pm0.10)times10^{-11}M_{odot}yr^{-1}$, which is compatible with the current concept of CV evolution at ultrashort orbital periods.
We present phase-resolved spectroscopy of the short period cataclysmic variable WZ Sge obtained with the Hubble Space Telescope. We were able to resolve the orbital motion of a number of absorption lines that likely probe the environment near the acc
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We report on a superoutburst of a WZ Sge-type dwarf nova (DN), ASASSN-15po. The light curve showed the main superoutburst and multiple rebrightenings. In this outburst, we observed early superhumps and growing (stage A) superhumps with periods of 0.0
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