Scientists have studied the magnetic field of a white dwarf, which, according to forecasts, should approach the solar system in 29 thousand years. It turned out that the unusual object "cheated" measuring devices with its incredibly strong magnetic field.
In 2022, astronomers Vadim Bobylev and Anisa Baikova identified in the data of the space telescope "Gaia" more than 30 stars that approached our system in the past or will approach in the future at a distance of less than one parsec (3.26 light-years), that is closer than Alpha Centauri - the closest star system to us.
The three "record holders" were: GJ 710, which will approach us in 1.35 million years, HD 7977, which approached the Sun 2.83 million years ago, and the white dwarf WD 0810-353. According to Gaia, meeting with the latter will occur in just 29 thousand years, the star will approach the solar system at a distance of about 31 thousand astronomical units, that is, it will cross the Oort cloud - part of our system.
The Oort cloud is a hypothetical region of the solar system where many icy objects have been flying around since the formation of the system. It is located between 50,000 and 100,000 astronomical units away. Scientists believe that long-period comets come to us from there. It is the Oort cloud that poses the main danger in the case of convergence of the solar system with other stars.
It's extremely unlikely that any star will collide with the Sun. But there is no doubt that such a massive object will gather from the orbits of small components of the Oort cloud and those "rain down" on the planets of the solar system.
Therefore, scientists decided to look closely at WD 0810-353 and double-check the measurements from "Gaia", which initially seemed to astronomers suspicious: spectral data did not match the expected values for a white dwarf.
In the database "Gaia" radial speed - how fast the object is approaching us - was calculated from the spectrum of radiation. That's where the error occurred. The white dwarf WD 0810-353 has a very strong magnetic field of 30 megahauss. As explained by the authors of the new publication, even a field of less than megaussa is able to "split" spectral lines. And scientists were not sure that the effect of the strong field was taken into account in calculations on the data "Gaia".
Therefore, for a new study astronomers used the spectrograph FORS2 telescope VLT. After obtaining more accurate data from the spectrum of WD 0810-353, the scientists modeled the object's magnetic field and the effect of this field on the radial velocity estimate.
"We found that the approach velocity given in the Gaia project data is incorrect, and the predicted approach between WD0810-353 and the Sun will not actually occur. Moreover, WD0810-353 is probably not moving towards the Sun at all," - commented on the results of the study co-author Stefano Bagnulo (Stefano Bagnulo), an astronomer from Armagh Observatory (Armagh Observatory & Planetarium, UK).
But it turned out that WD0810-353 is extremely interesting in itself as one of the closest to us white dwarfs with a strong magnetic field. Its age - about three billion years, and it is just entering the cooling phase, when on the surface of such objects appear very powerful magnetic fields. Therefore, the authors of the study, published in The Astrophysical Journal, called for further observations.
