An international team of astronomers, including researchers from the University of Chicago, USA, has made the rare discovery of a planetary system whose parent star is similar to the Sun. Particularly intriguing was the star's unusual composition, which indicates that it is swallowing up some of its planets.
Researchers led by Jorge Melendez studied the star HIP68468, which is located 300 light-years away. Using a 3.6-meter telescope at La Silla Observatory, Chile, these scientists discovered their first exoplanet in 2015. The team's newer discovery is still awaiting confirmation, but it involves two candidate planets - super neptune and super earth. The orbits of these planets lie surprisingly close to the parent star, with one of the planets 50 percent more massive than Neptune and at the same distance from the parent star as Venus from the Sun. Another of these planets, the first super-earth to be discovered in orbit around a star like the Sun, has a mass of about three Earth's masses and is so close to the star.which makes one revolution in orbit around it in just three days.
"These two planets most likely migrated inward from the outer part of the planetary system, while the inner planets of the system were pushed out of it or absorbed by the star," the authors write in their work.
The chemical composition of the star HIP68468 indicates the absorption of planets by it, since it contains an excess amount of lithium, which intensively decomposes in the interiors of stars, but is relatively stable in the colder interiors of planets. Obviously, this lithium hit the star relatively recently, probably through the absorption of one or more planets in the system of this star, the scientists conclude.
The study was published in the journal Astronomy & Astrophysics.
