NASA's exoplanet flotilla has discovered its first Earth-sized world in a near-Earth system

A spaceship launched last year in order to find new exoplanets fell on a planet the same size as ours.

NASA's Transiting Exoplanets Survey Satellite (TESS) survey satellite located its first Earth-sized planet in a system about 53 light-years from Earth.

Scientists estimate that the far-distant world is about 2.7 times larger than the Earth and could harbor a substantial atmosphere.

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The planet, nicknamed HD 21749b, is what is called a sub-Neptune exoplanet, which means it has a smaller mass than Neptune and Uranus. It has an orbit of about 36 days, which gives it the longest period of a planet that TESS has yet found, and its mass is about 23 times that of the Earth.

After the TESS signals suggested the presence of a planet gravitating around a star around 80% of the solar mass, researchers were able to confirm the detection using the Planet Finder spectrograph on the Magellan II telescope. Observatory Las Campanas de Carnegie in Chile.

The planet, nicknamed HD 21749b, is what is called a sub-Neptune exoplanet, which means it has a smaller mass than Neptune and Uranus.

It has an orbit of about 36 days, which gives it the longest period of a planet that TESS has yet found, and its mass is about 23 times that of the Earth.

Scientists hoping to find mainly planets whose orbital periods are less than 10 days, the team says this discovery is unusual.

"The PFS is one of the only instruments in the southern hemisphere that can do this type of measurement," said Johanna Teske of the Carnegie Institution for Science.

"This will be a very important part of the further characterization of the planets discovered by the TESS mission."

Researchers now hope to refine their measurements to better understand the atmosphere.

Unlike the Earth, the new planet is not a rocky planet and its atmosphere would be cooler.

According to the team, the planet also has a "brother", which orbits around its host star over a period of about eight days.

"Measuring the exact mass and composition of such a small planet will be difficult, but even more important to compare the HD 21749c to the Earth," Wang said.

"The Carnegie PFS team continues to collect data on this object for this purpose."

Scientists say that it is probably the first of many planets the size of the Earth that TESS will find during his surveys.

The revolutionary ship can measure the properties of small exoplanets, which was never possible before.

"For very close and very bright stars, we expected to find up to twenty Earth-sized planets," said lead author Diana Dragomir of the Kavli Institute for Space Research and Development. astrophysics at MIT.

"And here we are – it would be our first, and it's an important step for TESS, and it sets the path for finding smaller planets around even smaller stars, and these planets can potentially be habitable."

WHAT IS SPACECRAFT TESS?

NASA's new "planet fighter", which is expected to succeed Kepler, is equipped with four cameras allowing it to view 85% of the total sky, while it is looking for exoplanets orbiting stars around the world. less than 300 light-years away from the planet.

By studying much brighter objects than Kepler's targets, it is hoped that TESS could discover new clues about the possibility of living elsewhere in the universe.

His four wide field cameras will see the sky in 26 segments that he will observe one by one.

In its first year of operation, it will map the 13 sectors that make up the southern sky.

Then, the following year, he will cross the northern sectors.

"Kepler taught us that there were more planets than stars in our sky and now, TESS will open our eyes to the variety of planets surrounding some of the closest stars," said Paul Hertz. , director of the astrophysics division at NASA headquarters.

"TESS will launch a larger network than ever before for enigmatic worlds whose properties can be explored by NASA's next James Webb Space Telescope and other missions."

Tess is 1.5 meters wide and shorter than most adults.

The observatory is 1.2 meters long, not counting the solar wings folded for launch, and weighs only 362 kilograms.

NASA says its size varies between the size of a refrigerator and that of a stacked washer and dryer.

Tess will target a single elongated orbit that passes 45,000 km from the Earth at one end and as far as the moon's orbit at the other end.

It will take two weeks for Tess to go around the Earth.