Western University of Ontario | 2020 Jun 24
Western astronomers may have spotted six new moons orbiting planets in solar systems far from our own – an otherworldly discovery so rare it must wait on future technologies to confirm. Until then, however, the mere possibility of the find sparks excitement over our biggest questions about the universe. ...Artist's conceptions of three of the six exomoon candidate systems from Fox & Wiegert
(2020) together with the Earth-Moon system. All systems are to the same scale and the
camera is at the same distance from each to make comparison easy. Includes KOI-268,
Kepler 517 (KOI-303) and Kepler 1000 (KOI-1888).
Credit: Paul Wiegert, Chris Fox (Western University)
Exoplanets are planets orbiting stars other than our Sun; the moons of these planets are called exomoons.
While more than 4,000 exoplanets have been discovered since the mid-1990s, none have a confirmed moon orbiting them, although a number of prime candidates have been identified in recent years. ...
Ranging between 200 and 3,000 light years away, the exoplanets reported in the Western study were discovered using data from the Kepler space telescope -- a planet-hunting spacecraft decommissioned by NASA in 2018. They were revealed by the transits (or dimmings) of their star's brightness when an exoplanet passes in front of it. Their moons, however, were not so easily spotted. ...
If an exoplanet orbits its star undisturbed, the transits it produces occur precisely at fixed intervals.
But for some exoplanets, the timing of the transits is variable, sometimes occurring several minutes early or late. Such transit timing variations -- known as TTVs -- indicate the gravity of another body. That could mean an exomoon or another planet in the system affecting the transiting planet. ...
Exomoon Candidates from Transit Timing Variations: Six Kepler Systems with
TTVs Explainable by Photometrically Unseen Exomoons ~ Chris Fox, Paul Wiegert
- arXiv.org > astro-ph > arXiv:2006.12997 > 23 Jun 2020