A new clue has just been found that can help solve the mystery of a strange darkening star. KIC 8462852, also known as Boyajian’s Star, appears to have a binary companion that may contribute to its irregular decrease in brightness.
If confirmed with more detailed observations, the newly discovered companion astronomers can help solve the ongoing mystery of KIC 8462852.
The star was discovered in 2015 by astronomer Tabetha Boyajian (so it was previously Tabby’s Star) and has been a real puzzle ever since. It is a yellowish-white dwarf star at about 1,470 light-years, and it disappears illegally. The duration of the star’s eclipse, or depth, is not frequent – some of the declines in starlight were up to 22 percent.
This behavior excludes planets; if an exoplanet moves between a star and the earth as it orbits, it will fade the star by a small amount – 1 percent or less – at regular intervals.
Furthermore, when Boyajian’s Star fades, some wavelengths are blocked more than others. This excludes a solid object (such as a foreign megastructure, as proposed in 2016), which will block all wavelengths equally.
So far, the most likely explanation appears to be optically thin dust and debris, possibly from broken planetary animals or comets on eccentric orbits, combined with normal luminosity variations of the star itself.
The presence of a binary star on a wide orbit can help explain the presence of all this material, which provides additional gravity disturbances to disrupt bodies around the orbit.
Since 2016, a team of astronomers led by Logan Pearce of the University of Arizona has been trying to confirm the potential connection of a nearby star to KIC 8462852. The Astrophysical Journal.
It is difficult to measure space in three dimensions. Stars that look fairly close together can actually be at very different distances from the viewer. Therefore, Pearce and the team used observations for five years to make accurate astrometric measurements of the faint star that looked close to KIC 8462852.
“In this work, we use three periods of Keck / NIRC2 astrometry spanning five years to revisit the status of the closest companion of KIC 8462852, showing that it is a common motion pair and a gravity-bound binary system. , “they write paper.
In addition to the observations of Keck Observatory, the release of astrometric data from the Gaia satellite in 2020 – the most complete and accurate three-dimensional map of the Milky Way to date – also included the dim star, with measurements consistent with the findings of the team.
The two stars are separated by a distance of 880 astronomical units. Boyajian’s Star, or KIC 8462852 A, is the larger star, about 1.36 times the mass and 1.5 times the size of the Sun. The companion, KIC 8462852 B, is a red dwarf star about 0.44 times the mass and 0.45 times the size of the sun.
At such a wide orbit, KIC 8462852 B would probably have no direct effect on the brightness of KIC 8462852 A. But it could still play a role in the mysterious fluctuations of the larger star, the researchers said.
“The binary companion can affect the long-term evolution of the system,” they wrote in their article.
Scientists have previously found that stellar issues with large distribution can be pushed by larger gravitational forces to move very close to their mutual center of mass several times over the course of about 10 billion years.
This in turn can lead to the disruption of planets and other small bodies in orbit where they are stretched and torn apart by gravity interactions, leading to clouds of debris.
The scenario has yet to be confirmed. At such a wide separation, the two stars would have had a very long orbit, and the observations taken were not sufficient to characterize this orbit. KIC 8462852 B may be a star ejected from the system; or the two stars may be members of a group moving together.
According to the researchers, a binary is the most likely explanation for their measurements of the two stars, but future measurements of the pair will be needed to better understand their relationship. This may help to confirm or exclude the role of KIC 8462852 B in the alternating brightness of the star.
But do not fear all the mystery lovers out there. There are other strange obscuring stars out there, including a star for which the binary companion has already been set off, and a tantalizing collection of 21 stars that may be even stranger.
The research of the team was accepted The Astrophysical Journal, and is available on arXiv.