An international team of astronomers has identified a new extrasolar planet using data from the Kepler Space Telescope, which is currently on an extended mission known as K2. This newly discovered exoplanet, designated EPIC 228735255b, is a so-called "hot Jupiter" orbiting its parent star in an eccentric orbit.
This planet was first noticed during observations carried out as part of the K2 mission in July 2016, when the light curve of the parent star EPIC 228735255 (pictured) was obtained, which is close in size and mass to our Sun. To confirm the planetary status of the newly discovered object, a team of researchers led by Helen Giles of the Geneva Observatory, Switzerland, conducted additional observations with several ground-based telescopes.
These observations, conducted in early 2017, allowed the team to confirm the planetary status of EPIC 228735255b and determine its fundamental parameters. According to these measurements, the mass of the planet EPIC 228735255b is approximately equal to the mass of Jupiter, and the radius is 1.09 that of the largest planet in the solar system. Therefore, the average density of the planet's matter is approximately 27 percent lower than the density of Jupiter's matter, that is, the planet is slightly “bloated”.
The planet EPIC 228735255b lies in a slightly eccentric (e = 0.12) orbit around the parent star and makes one complete revolution along it in 6.57 days. The predicted equilibrium temperature on this planet is 1114 Kelvin.
All of these parameters indicate that planet EPIC 228735255b is another example of a "hot Jupiter" class planet. Hot Jupiters are gas giants similar in characteristics to Jupiter, which orbit their parent stars with a period of no more than 10 days. Temperatures are high in the outer atmosphere of these planets because they are very close to their parent stars.
A message with these results appeared on the arxiv.org server of preliminary scientific publications.
