Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5487787 | New Astronomy | 2017 | 6 Pages |
Abstract
We present the photometric results of the eclipsing cataclysmic variable (CV) WZ Sge near the period minimum (Pminâ). Eight new mid-eclipse times were determined and the orbital ephemeris was updated. Our result shows that the orbital period of WZ Sge is decreasing at a rate of PË=â2.72(±0.23)Ã10â13ssâ1. 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 Pminâ of WZ Sge is â¼ 77.98( ± 0.90) min. If the orbital period decreases at the current rate, WZ Sge will evolve past its Pminâ after â¼ 25.3 Myr. Based on the period evolution equation we find MË2â4.04(±0.10)Ã10â11Mâyrâ1, which is compatible with the current concept of CV evolution at ultrashort orbital periods.
Keywords
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Physical Sciences and Engineering
Physics and Astronomy
Astronomy and Astrophysics
Authors
Z.-T. Han, S.-B. Qian, Irina Voloshina, L.-Y. Zhu,