Astronomers not only figured out that unusual star systems can have planets, but also proposed a new method of their detection.
There is such a type of star systems in the Universe, which is called cataclysmic variables (CVs). These are binary star systems that consist of a dead star – a white dwarf and a companion star, the substance of which absorbs this white dwarf. Most of these donor stars are red dwarfs. A new study has shown that exoplanets can orbit these stars, and scientists have proposed a new way to find them, which differs from the popular transit method, reports ScienceAlert.
Cataclysmic variable stars come in many types, but they all have the same composition. They consist of two stars:
- A white dwarf that has about three-quarters the mass of the Sun and the diameter of the Earth;
- And mostly next to this dead a star at a very close distance is a companion star – a red dwarf, the mass of which can be from 0.07 to 0.3 masses of the Sun, and the diameter of these stars is equivalent to a fifth of the diameter of the Sun;
- The white dwarf in this system is called the main star, as it is more massive, and the red dwarf is called the donor star, since the dead star takes matter from it and, as a result, an accretion disk is formed around the white dwarf.
The matter in the accretion disk heats up, and this leads to an increase in the level of luminosity, which can block the light from both stars. But if there is a third object nearby, that is, an exoplanet, then its gravity affects the movement of stellar matter from one star to another. And this process affects the luminosity of the entire star system. This is how this planet can be detected, scientists say.
Four of the two star systems have planets
A group of scientists led by Carlos Chavez from the Autonomous University of Nuevo Leon, Mexico, decided to test their theory on the cataclysmic variable stars LU Giraffe, QZ Serpens, V1007 Hercules and BK Lynx. These stars are in constellations corresponding to the name.
A new study has shown that the brightness of this system varies due to the fact that two of the four studied spacecraft actually contain a body that looks very much like an exoplanet. Thanks to the analysis, astronomers were able to learn about the distance at which these planets revolve around two stars and their approximate mass.
“We believe that these potential planets can influence the change in the brightness of the spacecraft, because these changes have a long period – from 42 to 265 days,” says Chavez.
A new method for detecting planets
According to the scientist, this study offers a new method for detecting exoplanets in deep space. Now the most popular search method is the transit method. A planet can be detected when it passes in front of its star and the luminosity of the latter changes.
“But this planet must be viewed from a certain angle, otherwise the dips in the light of the star will not be noticeable. Using our method, planets can be look from different angles and this will make it possible to find even more such space objects,” says Chavez.
Focus already wrote that astronomers managed to detect a unique triple star system, which previously consisted of four stars. In this system, as well as in catalytic variables, there is also a star, which, however, has long swallowed up its companion.
As for the study of the Universe in general, Focus already wrote that there are five most popular hypotheses according to which our universe will someday disappear, but this will happen in different ways and at different times.