Tomasz Nowakowski is a writer for Phys.org.
Analyzing data from the XMM-Newton and NASA TESS telescopes, German Astronomers inspected a highly variable polar known as V496 Uma. The results of the study were published on arXiv.org.
There is a white dwarf and a normal star companion in a cataclysmic variables. They increase in brightness by a large factor, then fall back to a quiescent state. There is a very strong magnetic field in white dwarfs that make polars a subclass of cataclysmic variables.
In 2012 it was identified as a CV after changing its brightness by about 2 mag within 30 minutes. It is a non-eclipsing polar. The light curve shows a double peaked structure with the second hump being variable.
Samet Ok and Axel Schwope of the Leibniz Institute for Potsdam in Germany decided to comb through the archival data from XMM-Newton and TESS, hoping to get more insights into the properties of this highly variable polar Astrophysics.
The thermal, temporal, and geometric behavior of V496 UMA is investigated in the study.
The study confirmed that the optical light curve displays a variable behavior. The light curve is characterized by two humps. The system shows a periodic variability at a time of approximately 91.06 minutes.
The X-ray light curve of V496 UMa is double-humped and shows a dip. The source exhibits a multi-temperature spectrum in X-rays. It has a prominent blackbody emission, which is typical for polars.
It was also found that V496 Uma has two di erent mass accretion states in the SED, an active state and an inactive state. The bolometric X-ray luminosity of this system in a high state matches the average X-ray luminosity of the so-called intermediate polars.
The system most likely consists of a main-sequence donor star and a white dwarf with a mass not exceeding 10,000 K, as the researchers tried to determine the fundamental parameters.
The empirical relationship of Knigge et al. was used in our attempt to determine the type of secondary. The authors of the paper concluded that a main-sequence star with a temperature of 10,000 K and a white dwarf represented quite well the energy distribution in the low accretion state.
More information: Samet Ok, Axel Schwope, XMM-Newton and TESS observations of the highly variable polar V496 UMa. arXiv:2205.10216v1 [astro-ph.SR], arxiv.org/abs/2205.10216The Science X Network will be launched in 2022.
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