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2 Earthlike planets spotted in newly discovered nearby star system

A visualization of two Earth-like exoplanets discovered by NASA's TESS space telescope around the dwarf star HD 260655.
Two Earth-like exoplanets have been discovered orbiting the dwarf star HD 260655 only 33 light-years from Earth. (Image credit: MIT)

A planetary system with two Earthlike planets has been discovered only 33 light-years away from us. 

This exciting solar system is one of the nearest to Earth and was spotted by NASA's Transiting Exoplanet Survey Satellite (TESS) in October 2021. It took several months for scientists to confirm that the periodic dips in the brightness of the star HD 260655 were caused by orbiting planets crossing in front of its disk. The scientists were finally able to announce the discovery at a meeting of the American Astronomical Society in Pasadena, California, on Thursday (June 16). 

Related: These 10 super extreme exoplanets are out of this world

The neighboring solar system contains "at least" two rocky planets the size of our Earth, but neither of these is likely to host life, the scientists said in a statement (opens in new tab). Calculations of the planets' orbits revealed that both of those worlds circle their star at a distance that is too close to allow the existence of liquid water on their surfaces. 

In fact, one of those two planets, called HD 260655b, about 1.2 times as big as Earth, takes only 2.8 days to orbit its star. The other, HD 260655c, which is 1.5 times Earth's size, needs 5.7 days to complete one orbit. 

The planets' parent star is a so-called M dwarf, a tiny star about a tenth of the size and brightness of the sun. Still, temperatures on the planets' surfaces reach a scorching 818 degrees Fahrenheit (437 degrees Celsius) and 548 degrees F (287 degrees C) respectively.

"We consider that range outside the habitable zone," Michelle Kunimoto, a postdoctoral researcher in astronomy at the Massachusetts Institute of Technology (MIT) and one of the lead scientists behind the discovery said in the statement.

Still, these two exoplanets will provide an exciting new opportunity to learn more about Earth-like worlds outside our solar system.

"Both planets in this system are each considered among the best targets for atmospheric study because of the brightness of their star," Kunimoto said. "Is there a volatile-rich atmosphere around these planets? And are there signs of water or carbon-based species? These planets are fantastic test beds for those explorations."

The researchers continue studying the star system hoping it might contain even more planets, some of which, perhaps, could be a little farther away from the star.

"There might be more planets in the system,” Avi Shporer, MIT's research scientist for the TESS mission and co-author of the discovery, said in the statement. "There are many multiplanet systems hosting five or six planets, especially around small stars like this one. Hopefully we will find more, and one might be in the habitable zone."

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Tereza Pultarova
Senior Writer

Tereza is a London-based science and technology journalist, aspiring fiction writer and amateur gymnast. Originally from Prague, the Czech Republic, she spent the first seven years of her career working as a reporter, script-writer and presenter for various TV programmes of the Czech Public Service Television. She later took a career break to pursue further education and added a Master's in Science from the International Space University, France, to her Bachelor's in Journalism and Master's in Cultural Anthropology from Prague's Charles University. She worked as a reporter at the Engineering and Technology magazine, freelanced for a range of publications including Live Science, Space.com, Professional Engineering, Via Satellite and Space News and served as a maternity cover science editor at the European Space Agency.