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Located just 31 light-years away, one of the closest exoplanets ever detected could harbor liquid water on its surface. TESS for “Transiting Exoplanet Survey Satellite” – NASA’s super-powerful space telescope scanning the sky for extraterrestrial worlds – spotted a new planet orbiting a nearby star in the constellation Hydra.
When astronomers did further analysis on the star, they discovered two other planets orbiting around.
One of the planets, called GJ 357 d, could harbor liquid water if it has a fairly thick atmosphere and is rocky. It is one of the 45 closest exoplanets confirmed to date, out of a total of 4,025 planets identified so far outside our solar system.
This system of planets is the third closest system identified by the “transit” method, in which telescopes observe small holes in the brightness of a star that could be caused by a planet passing in front of it. The Kepler telescope pioneered this technique, which was further refined by the TESS telescope.
The promising planet is in the “habitable zone” of its star, at a distance where a rocky planet could have the right surface temperature for liquid water to exist.
“GJ 357 d is located inside the outer edge of the habitable zone of its star, where it receives about the same amount of stellar energy from its star as Mars receives from the Sun,” said Diana Kossakowski, Member of the team that discovered the planet, in a statement.
“If the planet has a dense atmosphere – it will take further analysis to determine it – it could trap enough heat to warm the planet and allow liquid water to flow to its surface,” said Diana Kossakowski. And to add: “If the planet has no atmosphere, its surface would be about -17 degrees Celsius, well below the freezing temperature of water.”
The mass of GJ 357 d is equivalent to at least 6.1 times that of the Earth, and the planet gravitates around its tiny star every 55.7 days. Scientists can not say much else about it without further study.
TESS, NASA’s most powerful newer-looking telescope in history, observes thousands of stars in transit. The telescope observes part of the sky for 27 days in a row, before moving on to a new location. It divides each half of the sky (North half and South half) into 13 plates, as shown in the NASA chart below.
The spacecraft completed the southern half of its trip this month and turned north. At the end of his mission, next year, at the same time, TESS will have observed more than 85% of the sky.
So far, the telescope has found more than 850 new potential planets. The next step is for terrestrial telescopes to examine the stars around which these planets could orbit and detect if they actually exert a gravitational pull.
It was this process that allowed researchers to find the planet GJ 357 d. While doing this confirmation work for the first planet spotted by TESS, they noticed gravitational pulls of two others. TESS could not locate these two planets because their orbits do not pass between their star and the telescope.
So far, only 24 exoplanets identified by TESS have been confirmed. Earlier this week, astronomers confirmed the presence of three exoplanets, including a “super-Earth”, although none are considered to have liquid water.
Scientists expect the telescope to identify thousands of potential exoplanets by the end of the mission. Some of them could be habitable, including GJ 357 d.
“The team is currently focusing on finding the best candidates to be confirmed by ground tracking,” said Natalia Guerrero, who leads the MIT team that identifies potential exoplanets, in a NASA press release aired on Monday. last week.
“But there are still many other potential exoplanets in the data to analyze, we only see the tip of the iceberg here.”
Source: BusinessInsider
