A new catastrophic variable discovered by astronomers

By analyzing data from the European Space Agency's XMM-Newton and Gaia satellites, astronomers from the Leibniz Institute for Astrophysics Potsdam (AIP) in Germany and elsewhere have discovered a new cataclysmic variable magnetic system, most likely of the polar type. The result was reported in a paper paper It was published on March 21 on a preprint server arXiv.

CVs are binary star systems that include a white dwarf and a companion regular star. They irregularly get brighter by a large factor, then drop back to rest. Polar CVs are a subclass of cataclysmic variables that are distinguished from other CVs by the presence of a very strong magnetic field in their white dwarfs.

A team of astronomers led by Samit Oak of AIP has identified a new cataclysmic variant, which has been given the designation XMM J152737.4-205305.9 (or XMM 152737 for short), by linking the CV candidate catalog released by Gaia Data Release 3 (DR3) with an archive XMM-Newton.

“In order to detect and identify new catastrophic magnetic variants, we have linked the source coordinates in this catalogue [DR3] “Within the XMM-Newton data archive,” the researchers wrote in the paper.

According to the study, XMM 152737 has an odd period that is consistent with the synchronous rotation characteristic observed at the poles. The system displays harmonics in its energy spectrum, and has a relatively short orbital period, which is typically observed at known polarity.

The source was found to display two distinct dips showing a repeating pattern with a fine period of approximately 112.4 minutes. Scientists explained that such decreases may be caused by the eclipse of the white dwarf by the donor star or the blocking of the accretion region on the white dwarf by the accretion stream.

Observations show that XMM 152737 has prominent emission lines that correspond to hydrogen and helium. This result strongly suggests that the object is a polar-type catastrophic variable.

The study found that XMM 152737 is located about 3,770 light-years from Earth, and its X-ray luminosity is estimated at between 30 and 60 nanoillion erg/s. Assuming the system experiences eclipse, the paper's authors calculated that the white dwarf and secondary star have masses of 0.8 and 0.14 solar masses, respectively.

Summarizing the results, the researchers noted that further observations of XMM 152737 are needed in order to determine the origin of the observed dips in this system. This could shed more light on the characteristics of this catastrophic variant and confirm its polar classification.