Researchers from the Yunnan Observatories of the Chinese Academy of Sciences have found unusual variations in successive luminosity curves of the transit satellite for the exoplanet survey (TESS) of the ultra-soft X-ray source V Sge. This is the first evidence that there may be uneven near-star matter around the ultra-soft source of X-rays.

This work has been published in Monthly reports of the Royal Astronomical Society February 2.

V Sge is a unique eclipse double cataclysm and recognized as a super-soft X-ray source, consisting of a compact main component of the white dwarf and a star of the main sequence star. The white dwarf is continuously gaining mass from the satellite through increase drive.

To further study their mass exchange and the final evolution of the orbit, the researchers tracked them with a one-meter telescope at the Yunnan Observatories and then obtained minimal eclipse times.

Combined with a more continuous TESS light curve, the researchers analyzed in detail the variation of the V Sge orbit period. As a result, the orbital period is continuously decreasing, suggesting that a more massive satellite transmits material to the white dwarf during its evolution in the thermal time scale, and possible mass loss from the accretion disk takes away the angular momentum of this system.

Based on the results of the orbital period analysis, the researchers derived the latest velocity orbital period changes for this system and then, in the case of subsequent angular momentum loss (CAML) caused by wind accretion disk, they estimated the range of mass transfer rate and mass build-up rate. Moreover, it can be roughly estimated that V Sge could reach the Chandrasekhar limit in at least 1 million years and then explode as a supernova type Ia.

In addition, researchers have found evidence of the existence of uneven stellar matter surrounding an ultra-soft X-ray source. They found that there are peculiar and irregular changes in the more continuous light curve TESS V Sge, which may be caused by the effect of extinction of non-uniform stellar matter and dynamic changes in shape accretion disk edge.

These options give researchers the opportunity to understand mass transfer and wt the ejection process is better. However, the law of these variations and the mechanism that leads to them have yet to be confirmed.

Researchers from the Yunnan Observatories of the Chinese Academy of Sciences have found unusual variations in successive luminosity curves of the transit satellite for the exoplanet survey (TESS) of the ultra-soft X-ray source V Sge. This is the first evidence that there may be uneven near-star matter around the ultra-soft source of X-rays.

This work has been published in Monthly reports of the Royal Astronomical Society February 2.

V Sge is a unique eclipse double cataclysm and recognized as a super-soft X-ray source, consisting of a compact main component of the white dwarf and a star of the main sequence star. The white dwarf is continuously gaining mass from the satellite through increase drive.

To further study their mass exchange and the final evolution of the orbit, the researchers tracked them with a one-meter telescope at the Yunnan Observatories and then obtained minimal eclipse times.

Combined with a more continuous TESS light curve, the researchers analyzed in detail the variation of the V Sge orbit period. As a result, the orbital period is continuously decreasing, suggesting that a more massive satellite transmits material to the white dwarf during its evolution in the thermal time scale, and possible mass loss from the accretion disk takes away the angular momentum of this system.

Based on the results of the orbital period analysis, the researchers derived the latest velocity orbital period changes for this system and then, in the case of subsequent angular momentum loss (CAML) caused by wind accretion disk, they estimated the range of mass transfer rate and mass build-up rate. Moreover, it can be roughly estimated that V Sge could reach the Chandrasekhar limit in at least 1 million years and then explode as a supernova type Ia.

In addition, researchers have found evidence of the existence of uneven stellar matter surrounding an ultra-soft X-ray source. They found that there are peculiar and irregular changes in the more continuous light curve TESS V Sge, which may be caused by the effect of extinction of non-uniform stellar matter and dynamic changes in shape accretion disk edge.

These options give researchers the opportunity to understand mass transfer and wt the ejection process is better. However, the law of these variations and the mechanism that leads to them have yet to be confirmed.