The discovery of exoplanets is no longer surprising, because so far thousands of them have been discovered. But occasionally one of them catches the eye because of its particular characteristics. Recently, astronomers have discovered one of these ‘differences’. The LTT 1445Ab is an exoplanet located in our galactic neighborhood, which has no less than three red suns.

This exoplanet is a rocky world, slightly larger than Earth. It orbits around the largest star in a three-star system, about 22.5 light years from our planet . A curious detail is that this exoplanet travels between Earth and its host star on each pass.

The three stars or three suns of this system are dwarfs, reddish, active stars smaller than our sun. This makes LTT 1445Ab the second known transit exoplanet, closest to Earth, and the closest in orbit to a dwarf M.

The exoplanet

From the surface of this exoplanet, which orbits its main star just a tenth of the distance between the Sun and Mercury, “you would see a large orange sun and two much smaller orange suns seen from afar,” explains study author Jennifer Winters. “The primary star would be very large in the sky and very close. The other two are much more distant. They look 100 times brighter than Venus and about the same size as the sky.”

The study authors do not know exactly how or when these different suns rose on the planet . This is because, due to the distance, it is not possible to identify the angle or speed that is rotating.

Interestingly, scientists have studied these orbits for decades, never realizing the existence of this exoplanet. “The reason we probably haven’t met the exoplanet before is because it’s in this triple system. Many of these planetary search surveys avoid these types of systems,” Winters said.

Previous studies of three-star systems did not exactly look for traces of any exoplanets. And when it comes to exoplanet fighters, they rarely focus on multiple star systems.


Winters and his team were only able to discover the LTT 1445Ab thanks to data collected by the Transiting Exoplanet Survey Satellite, TESS. This satellite is the leading exoplanet hunter latest generation of NASA , released last year.

In the case of this triple system, Winters was particularly interested in M ​​dwarf research. This group of stars that had not been the focus of exoplanet research until then. According to Winters, these M dwarfs go through a long period of “adolescence” in which they are particularly active and emit a lot of radiation.

“We still don’t know if the planet’s atmospheres are able to survive the high radiation environment of an M dwarf when he is very young, so this will be an incredible opportunity to study this,” she said. “As it passes in front of its host star, it is illuminated by the light of its host star and we can study the types of molecules that are in its atmosphere. That is clear if it has an atmosphere.”

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