An international team of astronomers has uncovered the most ancient habitable exoplanet found to date. The discovery is all the more interesting because the planet originated outside of our Milky Way galaxy. At around 11.5 billion years old, the super-Earth is more than twice as old as our own planet and shows that habitable worlds were around much earlier in the universe's history than previously thought.
The highly unusual find came from a survey of nearby, low-mass stars led by Guillem Anglada-Escudé of Queen Mary University of London. As part of their trawl, the researchers observed Doppler shifts in the light from Kapteyn's star. Named after the Dutch astronomer who discovered it, it is one of the nearest stars to the Sun at just 13 light-years away. The Doppler shifts observed by the team were caused by two planets gravitationally tugging on their host and causing it to move slightly towards and away from the Earth. The researchers used new data from the HARPS spectrograph at the European Southern Observatory's La Silla observatory, the Planet Finding Spectrograph at the Magellan/Las Campanas Observatory in Chile, and the HIRES instrument at the W M Keck Observatory in Hawaii to measure tiny periodic changes in the motion of the star.To read more, click here.