NASA's TESS space telescope spotted its first exoplanet

Say hello to Pi Mensae c – a small Earth-like planet located about 60 light-years from our solar system. He is probably not able to sustain life, but it will be remembered as the first exoplanet detected by NASA's new TESS satellite.

On 18 April 2018, NASA launched the Exoplanets in Transit (TESS) satellite, which began operations on 25 July. In an early test of its powers, the satellite captured its first bright image on August 7th. last Monday.

As its name indicates, TESS is a planet search satellite. Using its four 10-centimeter optical telescopes, the satellite repeatedly analyzes vast areas of space and monitors the brightness of candidate stars. These data are then analyzed by astronomers, who search for periodic hollows in the brightness of a star – a possible sign of an exoplanet in orbit or transit passing in front of the star. It now seems that TESS made its first such finding.

"We report here the discovery of a planet in transit around Pi Mensae, exactly the type of planet that TESS was designed to detect," write the authors in their preprinted paper, which was uploaded to the arXiv server yesterday. .

Pi Mensae, also known as HD 39091, is a subgiant (dwarf) star of an unusually bright yellow. This star is visible to the naked eye and is located 60 light-years from Earth. Based on data collected from 25 July to 22 August, the TESS team concluded that Pi Mensae c, as the new planet is called, is a super-Earth. It is about 2.14 times the radius of the Earth and 4.82 times the mass of the Earth. Unfortunately, Pi Mensae is too close to his star to support life. Only one year on this planet lasts only 6.27 days. The planet may be uninhabitable, but its discovery is a positive sign that TESS is doing what it was built to do.

"TESS has begun to fulfill its promise to expand the collection of small planets in transit orbiting shining stars," write the study's authors. "Such stars allow accurate measurements of the mass and radius of this planet."

This is the second planet to have been detected around Pi Mensae. In 2001, astronomers spotted a huge planet in this system, Pi Mensae b, which represents nearly 10 times the mass of Jupiter, and the largest known planet of astronomers. This planet is so big that its surface is probably shining, causing some astronomers to think that it is more of a brown dwarf, a sort of star than a planet. It is also in an eccentric or very elliptical orbit, it takes 5.7 years to revolve around its host star.

The preliminary study of Pi Mensae c suggests that it contains water, methane, hydrogen and helium, in addition to a nucleus of rocky iron. That's about all we know about this planet, but the authors of the new study claim that future observations made by the Gaia spacecraft and the James Webb space telescope, which has not yet been completed, in will probably reveal more.

These observations may be far away, but astronomers will not have to wait long to study this star and its planets. TESS must collect an additional five months of data from this system, which allows the team to improve their knowledge of Pi Mensae c and search for other planets in transit.

This is the first of what should be a bunch of TESS discoveries. The mission is supposed to last two years, during which 500,000 stars will be studied. If all goes as planned, the space telescope could discover up to 1,000 new exoplanets.

So, there is a 999 to do.