TESS completes its first mission

NASA’s Transiting Exoplanet Survey Satellite (TESS) completed its first mission last July after two years of continuous sky observations.

This telescope, which began its observations in July 2018, is, like its predecessor Kepler, quite the hunter of exoplanets. During its first two-year mission, it confirmed the existence of 66 new exoplanets and identified nearly 2100 new exoplanet candidates.

Like Kepler, TESS detects exoplanets using the transit method, which consists of detecting periodic the dimming of a star caused when a planet passes in front of it. Unlike Kepler, who studied a very small portion of the sky, TESS observed more than 75% of the sky. Importantly, TESS has been looking for and finding exoplanets around stars relatively close – at least in astronomical terms – to our Sun.

The discovery of a planet around the young star AU Mic, to which our former postdoctoral researcher Jonathan Gagné contributed, is one of the important discoveries found during TESS’s initial mission.

Another important discovery, of interest to the general public and iREx researchers alike, is the discovery of TOI 700 d, a rocky exoplanet in the temperate (or habitable) zone of its star, i.e. where water, if there is water, could be found in liquid form.

An exoplanet the size of Neptune was also detected in orbit around a binary system, and another planet, potentially rocky, was found around a star that belongs to a triple star system, only 22.5 light years from Earth.

Artistic rendition of the planet LTT 1445 A b, which orbits the star LTT 1445 A. This star belongs to a triple system that includes two other stars, which can be seen in the upper right corner of the image. (Credit: ESO/M. Kornmesser)

Several of the confirmed and candidate exoplanets identified by TESS are currently being studied by iREx researchers using telescopes such as the SPIRou spectropolarimeter to learn more about their nature and composition. Several TESS planets will also be targets for the future James Webb Space Telescope, to be launched in October 2021.

After observing the Southern Hemisphere sky during its first year and the Northern Hemisphere sky during its second year, the TESS telescope will be moving into the second phase of its mission, which will end in September 2022. It will continue its operations by probing both hemispheres again in succession.

This video, in English, presents some of TESS’ outstanding discoveries. (Credit: NASA GSFC)

For more information

• NASA’s press release: NASA’s Planet Hunter Completes Its Primary Mission, published on August 11th 2020
• NASA’s TESS website