An international team of astronomers analyzed data from the latest phase of the Sloan Digital Sky Survey (SDSS) and found eight new cataclysmic variables. This is reported in a preprint of an article published in the arXiv repository.

Cataclysmic variables (or CVs) are binary star systems consisting of a white dwarf and an ordinary star, with the white dwarf accreting matter from its companion. From time to time, CV unevenly increases its brightness several times, after which it again goes into a state of rest. More than 500 objects of this type have been discovered within the SDSS.

As part of the fifth stage of the review, the spectra of already known CVs were analyzed and a search was made for new cataclysmic variables among the population of single and binary white dwarfs. Of the eight new CVs, four turned out to be systems of the WZ Sagittarius type — these are non-magnetic variables with a low accretion rate and rare superflares. One CV is novalike (brightness increases faster than decay), another belongs to the SU Ursa Major subtype, and the third is a polar. Subclass eight is yet to be determined.

SU Ursa Major differs from other variables in that it undergoes two distinct types of eruptions: short maxima lasting about two days with magnitudes ranging from 11.6 to 12.9 magnitudes, and longer maxima lasting 13 days with magnitudes ranging from 10.4 to 11. 8 magnitude. Polars are a subclass of cataclysmic variables characterized by the presence of a very strong magnetic field.

According to the study, none of the newly identified CVs show noticeable changes in brightness in their light curves. The orbital periods of all these eight variables have been measured to be less than 94 minutes, which is typical of older systems with low accretion rates. In addition to discovering new cataclysmic variables, astronomers have also spectroscopically confirmed 53 and refuted 11 other CV candidates.