An article to be published in “The Journal of Planetary Science” reports updates to the catalog of exoplanet candidates discovered with NASA’s Kepler space telescope which offers confirmation of the presence of seven planets in the Kepler-385 star system. This result was obtained by applying examination methods that were significantly improved compared to the past, obtaining new results from old observations. That includes this system among the very few with over six verified or at least candidate planets, making it particularly interesting. However, all of these planets are closer to their star than the inner edge of that system’s habitable zone and receive a significant amount of energy from it. The consequence is that none of them can be similar to Earth.
The mission of the Kepler space telescope ended almost exactly five years ago, leaving a treasure in a vast archive of observations. Over the years, researchers who focused on finding exoplanets have greatly improved the methods of examining those observations to obtain more precise data on the properties of stars and more accurate calculations of exoplanet orbits. The consequence is that even years after the observations it’s possible to make new discoveries.
In the case of the Kepler-385 system, with a star slightly larger and more massive than the Sun just over 4,600 light-years away from the solar system, the discovery of three planets around it was announced in 2014. Other traces of transits remained at the candidate level and only their re-examination led to a confirmation of their existence.
Astronomers are used to finding exoplanets orbiting close to red dwarfs but it’s less common to find seven exoplanets near a star more massive than the Sun. The closest two are a little larger than Earth, are probably rocky, and may have thin atmospheres. The other five are roughly twice the size of Earth and may have thick atmospheres.
New observations may help to better understand the characteristics of the exoplanets of the Kepler-385 system. For example, astronomers need to understand if some of them are mini-Neptunes and if some of them are losing their atmosphere due to intense emissions from their stars. The transformation of mini-Neptunes into super-Earths is a field of astronomical research, so astronomers working on it will be interested in this planetary system.
Astronomers expect to find gas giant planets in the system of a star similar to the Sun but at least for now, they haven’t detected any in the Kepler-385 system. Observing the transits of exoplanets in front of their stars makes it much easier to find planets close to them because the transit occurs often while Earth’s telescopes have the opportunity to see the transit of distant exoplanets much more rarely and therefore a lot of luck is needed to discover them. Finding them in the Kepler-385 system would make it even more interesting.
