NASA's planet-hunter uncovers its first world with two stars 1,300 light-years away

• The National Aeronautics and Space Administration’s (NASA) planet-hunting satellite has discovered its first planet with two stars.
• The Transiting Exoplanet Survey Satellite (TESS) observations show that the planet is nearly 7 times the size of Earth.
• Planets with two stars are extremely difficult to spot and only 12 such systems have been discovered so far.

Most planets orbit a singular star — like the Earth orbiting the Sun. Very few orbit two stars and they’re even more rare to find. In fact, only 12 such circumbinary planets have been discovered so far.

Nonetheless, the National Aeronautics And Space Administration’s (NASA) planet-hunting satellite was able to spot one such planet 1,300 light-years away — TOI 1338 b.

The Transiting Exoplanet Survey Satellite (TESS) revealed its observations during the 235th American Astronomical Society meeting in Honolulu on Monday.

A planet 7 times the size of Earth

Even though planets with two stars are rare, science-fiction has long hypothesized their existence. In Star Wars, Luke Skywalker’s home planet, Tatooine, has two Suns. In Hitchhiker’s Guide to the Galaxy, Magrathea is a circumbinary planet described as “the most improbable planet that ever existed”.

TESS’ discovery, the planet TOI 1338 b, is located in the Pictor constellation, which means ‘painter’ in Latin. It’s nearly 7 times the size of Earth. Its mass is closer to Neptune or Saturn. It’s the only known planet to in orbit around the two stars.

Observations of past circumbinary planets show that all but one of the systems has a planet bigger than Jupiter. Since it would be easier to detect bigger planets, scientists believe that there is a size limit to planets circling two stars.

TOI 1338 b orbits in almost exactly the same plane as the stars, so it experiences regular stellar eclipses. The stars take around 15 days to complete an orbit around each other. One is 10% bigger than our Sun, while the other is one-third the size.

Steller eclipses on TYC 2505-672-1, another planetary system with two stars, last as long as 3.5 years.

Pictor constellation’s potential for human habitation in outer space

The Pictor constellation is also home to Beta Pictoris, its second-brightest star which is surrounded by an unusual disk of carbon and only 63.4 light-years from Earth. It is the first debris disk to ever be found circling another star — akin to Earth’s Asteroid Belt.

An orange dwarf in the constellation, HD 40307, has six planets in orbit around it. One of those planets, HD 40307 g, is a potential super-Earth. This means that scientists believe that the planet’s atmosphere and terrain may be suitable for human habitation one day.

Another star in the constellation, a red dwarf around 12.76 light-years from Earth, was found to have two super-Earths in orbit around it in 2014.

Launched in April 2018, TESS had one mission — to search for planets outside our solar system, and hopefully find one capable of supporting human life. Even though it is yet to locate a planet fit as a back-up for Earth, this discovery is its first world with two stars.

See also:
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