Astronomers searching for the galaxy’s youngest planets have found compelling evidence for one unlike any other, a newborn “hot Jupiter” whose outer layers are being torn away by the star it orbits every 11 hours. Dubbed “PTFO8-8695 b,” the suspected planet orbits a star about 1,100 light-years from Earth and is at most twice the mass of Jupiter.
Exoplanet KELT-4Ab, about one and a half times the size of Jupiter, orbits the main star of a three-star system every three days. The system’s other two stars orbit each other once every 30 years while simultaneously orbiting the main star — and the planet — once every 4,000 years. The triple star system lies about 685 light-years from Earth.
Astronomers have observed the extreme temperature variations of HD 80606 b, a Jupiter-sized exoplanet with a highly eccentric, comet-like orbit that brings it scorchingly close to its parent star every 111 days. The researchers also calculated the planet’s rotation rate — the first exoplanet rotation rate ever obtained.
Astronomers have discovered the second known case of a four-star planetary system. The planet was known before and has a mass ten times that of Jupiter, but was thought to have only three parent stars, not four. The findings help researchers understand how multiple star systems can influence the development and fate of planets.