How did NASA discover 7 habitable planets

Discovered a habitable planet?

Actually, the researchers just wanted to prove the existence of a planet whose existence they had previously suspected. In doing so, they discovered two more planets, including the possibly habitable GJ 357 d.

All three newly discovered planets orbit the sun GJ 357 in the constellation Hydra. This sun has a third of the mass and size of our sun, announced the University of Göttingen, which is involved in international research. The astronomers' results first appeared in the journal "Astronomy & Astrophysics". With a distance of 31 light years, GJ 357 is comparatively close to us. A light year is the distance that light travels in one year. Our home galaxy, the Milky Way, is approximately 100,000 light years across.

A suspicious shadow on the sun

In February 2019, cameras from NASA's Transiting Exoplanet Survey Satellite (TESS) observed GJ 357. They discovered the existence of an exoplanet that partially covers the star in its orbit, thereby weakening its light. Voilà - FY 357 b.

The European Southern Observatory (ESO) on Mount La Silla, 600 kilometers north of Santiago de Chile

With the help of ground-based measuring instruments, the international team under the direction of the Institute for Astrophysics of the Canary Islands on Tenerife initially confirmed the existence of GJ 357 b. The researchers examined data collected since 1998 from the European Southern Observatory, the Campanas Observatory in Chile, the Keck Observatory in Hawaii and the Calar Alto Observatory in Spain.

Two hot planets

"We refer to GJ 357 b as so-called hot earth," explains Stefan Dreizler from the Institute for Astrophysics at the University of Göttingen. The planet has a calculated equilibrium temperature of around 250 degrees Celsius.

Model representation of the newly discovered trio of planets around the sun GJ 357

During their observations, the astronomers encountered signals from two other exoplanets: GJ 357 c and GJ 357 d. It is estimated that it is also very warm on planet GJ 357 c: it has a calculated equilibrium temperature of around 130 degrees Celsius, the researchers write. Its mass is at least 3.4 times that of the earth.

Minus 53 degrees Celsius

According to the researchers, planet GJ 357 d is far enough away from its sun to possibly be habitable - it lies on the outer edge of the still habitable zone of its star. With an estimated temperature of minus 53 degrees Celsius, the planet looks rather uninhabitable at first glance. But: "If the planet has a dense atmosphere, which has to be determined in future studies, it could capture enough heat to warm the planet and allow liquid water on its surface," the scientists write.

Size can only be estimated

According to the researchers, GJ 357 d receives about the same amount of energy from its central star as Mars does from the sun. It has a mass of at least 6.1 times that of the earth and orbits its star every 55.7 days at a distance of about 20 percent of the distance between the earth and the sun.

The size and composition of the exoplanet are unknown, but a rocky world with a corresponding mass would be between one and two times the size of the earth, said the University of Göttingen.

cw / wa (afp, dpa)