Lovers of the Star Wars saga surely remember that lyrical scene in which Luke Skywalker contemplates the double sunset of Tatooine. For in the world of exoplanets, this does not seem to be something out of the ordinary; What is extremely rare is discovering a world outside the Solar System with three stars , as just announced by a group of astronomers led by Jason Eastman, a research associate at the Harvard-Smithsonian Center for Astrophysics.
The planet with triple sunsets and triple sunrises is called KELT-4Ab and actually orbits a single star –KELT A– every three days, although the latter is orbited by another two –KELT B and KELT C–, which in turn, they carry out a complete orbital trajectory between them every 30 years. A complex celestial ballet that has been detected with the two robotic telescopes that make up the Kilograd Extremely Small Telescope (KELT) observatory, located in Arizona and South Africa.
According to Eastman, if we were on the surface of KELT-4Ab , which is roughly the size of Jupiter, the star KELT A would be 40 times larger than our Sun , while KELT B and KELT C would emit a brightness similar to that of full moon. In any case, it would be difficult for the observer to see these last two, which take a full orbit of the planet no less than 4,000 years, without the help of a telescope.
KELT-4Ab is the fourth known planet with three suns, but none has been found before with a main star this hot or this close to Earth : it is only 680 light-years away.
Image: Recreation of a sunset on the exoplanet HD 1885 Ab, whose system of three suns may be similar to that of KELT-4Ab. NASA / JPL-Caltech
