In a record-breaking 24 months, the TESS space telescope discovered almost 2000 alien worlds

In a record-breaking 24 months, the TESS space telescope discovered almost 2000 alien worlds

Astronomers have summed up the results of the main scientific program of the TESS space telescope. In two years, it found 2,241 exoplanet candidates, of which about 120 have already been confirmed. Among them are mini-Neptunes, super-earths, naked planetary cores, as well as objects in white dwarf systems.

TESS Observatory Achievements

The TESS Observatory was launched into space in the spring of 2018. It is equipped with four telescopes with sixteen 16.8-megapixel CCDs, each with a 24-by-24-degree field of view. The main purpose of the space telescope is to search for exoplanets near bright stars across the sky that are close to the Sun using transit photometry. In particular, TESS should find hundreds of planets with radii less than four Earth radii and determine the mass of several dozen of them.

During its work, TESS scanned 75 per cent of the celestial sphere, with observation times ranging from about 1 month in areas near the ecliptic to about 1 year in areas near the poles of the ecliptic.

The telescope discovered a lot of candidates for exoplanets and exocomets, flash type Ia supernovae in distant galaxies, and event tidal disruption of a star of a supermassive black hole. TESS has now completed its main observing program and is conducting a re-survey of the sky.

A group of astronomers led by Natalia M. Guerrero of MIT has published a catalogue of exoplanet candidates found by TESS over the two years of its main science program. In total, the observatory found 2241 candidates, of which about 120 were confirmed by observations of ground-based telescopes. Among them, there are many exoplanets of low mass, which are ideal for detailed studies, including searches for atmospheres.

Important Exoplanets

Researchers have identified a number of objects that are remarkable from their point of view. π Men c was the first exoplanet discovered by TESS and is a super-earth, or mini-Neptune, orbiting a yellow dwarf system 60 light-years away.

• TOI 700d is an Earth-like exoplanet that is in the habitable zone.

• TOI 125 was the first multi-planetary system for TESS to contain three mini-Neptunes and possibly two more small planets.

• LHS 1815 b was the first exoplanet with a thick disk in our galaxy.

• The exoplanet DS Tuc Ab is interesting for two reasons at once – it is in a visual binary star system and is so young that it has not yet completed its compression stage.

• LHS 3844b is a hot super-earth that orbits its star in only 11 hours.

• TOI-1259 consists of three types of objects at once: an orange dwarf star, a white dwarf, and a Jupiter-like exoplanet.

• TOI 1690b is a candidate for a giant exoplanet in a white dwarf and demonstrates that planets can survive migrations to orbits close to white dwarfs.

• The TOI 1266 system consists of two planets orbiting a red dwarf and makes it possible to study the processes of photoevaporation of exoplanet atmospheres.

• TOI 849b is a huge, dense core of a gas giant that has lost its atmosphere.

• Finally, HD 21749b became the observatory’s first long-period planet, with a year spanning 35.61 Earth days.

The past success of the Kepler Telescope

Before NASA sent the new-generation exoplanet hunter TESS, there was another observatory that searched for possible Earth-like worlds – Kepler.

The Kepler telescope was launched into space back in 2009. Its main task is to search and study planets and planetary systems in other stars. In the first three years of operation, the device discovered more than 3.5 thousand candidates for exoplanets, and most of them were small worlds, less than three times the size of Earth.

In March 2018, the mission team reported that fuel supplies onboard the telescope is running out. Without fuel, the observatory was unable able to correct its orientation in space. On August 29, Kepler began its 19th observation campaign, but on October 30, NASA decided to officially shut down the observatory due to frequent breakdowns and depleted fuel supplies.

Overall, Kepler studied more than 500,000 celestial objects and confirmed the existence of 2662 exoplanets. The mission proves the theory that there are many more planets than there are stars in our galaxy.