Today we have a post from Joey Schmitt, a graduate student in the Astronomy department at Yale University, where he is working with the exoplanet group led by Debra Fischer, and in particular he has been working on the follow-up of Planet Hunters planet candidates.
We’re happy to announce the discovery of a new planet discovered by Planet Hunters volunteers, which is now published in The Astrophysical Journal. You can read the article for free on the arXiv here.
The star (PH3/Kepler-289/KOI-1353/KIC 7303287) is young and Sun-like. Two planets in the system, with periods of 35 and 126 days, had been previously validated statistically, the outer planet being a gas giant. However, Planet Hunters volunteers discovered a third transit signal between these two planets at a period of 66 days (PH3 c).
A quirk in the system allowed us to actually measure the mass of all the planets using only the exact times that each planet transited. The outer two planets, PH3 c and d, do not have a constant period like most planets do. Instead, it oscillates around an average value in a regular manner, which meant that it had been missed by computer algorithms but was easy to ...