Danielle Futselaar
Astronomers have discovered an unusual exoplanet such as hot Jupiter, which orbits so close to the parent star that it provokes plasma flares on the surface of the luminary.
The star HIP 67522, which is slightly larger and colder than our Sun, is only 17 million years old. Two planets orbit around it, the closest of which, HIP 67522 b, makes a complete revolution in 7 days.
Such a close proximity of HIP 67522 b excites the star’s magnetic field and provokes plasma flares. The level of radiation directed toward the planet from the star destroys the thin atmosphere of HIP 67522 b and causes it to rapidly lose mass. Currently, the planet is almost the same size as Jupiter, but scientists estimate that in 100 million years HIP 67522 b will shrink to the size of Neptune.
The team of astronomers used the TESS telescope to survey the stars, proximity of planets to which it can excite magnetic fields and provoke flashes. Realizing that the star HIP 67522 was such a candidate, they studied it with the Cheops telescope.
«With Cheops, we saw more flares, bringing the total number to 15, almost all of which were in our direction as the planet passed in front of the star as viewed from Earth», — the study’s author notes Kateryna Ilin from the Netherlands Institute for Radio Astronomy.
The most important evidence was that the flares occurred when the planet passed in front of the star. This suggested, that the planet is gathering energy as it rotates and uses it to excite the star’s magnetic field lines, causing flares. To further study this unique phenomenon, scientists plan to conduct additional research using the TESS, Cheops, and other telescopes.
«I have a million questions because this is a completely new phenomenon and the details are not yet clear. There are two things that I think are most important to do now. The first is to look at the different wavelengths to find out what energy is being released in these flares — for example, ultraviolet and X-rays — particularly bad news for an exoplanet. The second task is to find and study other similar star-planet systems; by moving from one case to a group of 10-100 systems, theoretical astronomers will have a lot to work with», — adds Kateryna Ilin.
The results of the study are published in the journal Nature
Source: LiveScience