TESS Scans the Sky and Finds A Super-Earth and Another Smaller World

The Transiting Exoplanet Survey Satellite (TESS) continues exploring the vastness of space by surveying about 200,000 bright stars near the Sun, looking for distant alien worlds. Researchers have now reported discovering two completely new worlds.

Researchers found two new exoplanets orbiting the nearby star TOI-836 using the Transiting Exoplanet Survey Satellite (TESS). Apparently, the newly discovered worlds are equivalent to a super-Earth and a mini-Neptune. A paper published on the pre-print server arXiv.org on August 15 reports the finding.

It is possible to see thousands of stars in a dark night sky. Considering that all stars are suns, it makes sense for them also to have planets.

The Milky Way Galaxy is teeming with exoplanets since we now believe each star has a planetary system. Scientists are focusing their attention on the nearest stars, which are bright enough for us to study the planets further. A survey of the entire sky is necessary due to the spread of the nearest stars across the sky.

A NASA mission led by MIT, TESS is an all-sky survey to search for transiting exoplanets. A transiting planet is one that passes in front of the star as seen from a telescope and is the most successful discovery method for small exoplanets to date.

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In an attempt to find transiting exoplanets, TESS surveys about 200,000 bright stars near the Sun. As of this writing, over 5,800 candidate exoplanets (TESS Objects of Interest, or TOI) have been identified, with 233 exoplanets confirmed by experts.

Using TESS, a team of astronomers led by Faith Hawthorn of Warwick University, U.K., has confirmed two further alien worlds.

It is reported that transit signals have been found in the light curve of TOI-836 (or TIC 440887364), a K-dwarf star located some 90-light years away. Follow-up observations with the ESA’s CHaracterizing ExOPlanet Satellite (CHEOPS) and other ground-based facilities confirmed the planetary nature of these signals.

“In this paper, we have presented the TOI-836 system and the discovery of its two planets, TOI-836 b and TOI-836 c.”

In their research paper, the researchers explain that their discovery is derived from two sectors of TESS data, 11 from the first year of the experiment and 38 from the third year, respectively, with a 2-minute cadence, and five observations from space from CHEOPS between 2020 and 2021, complemented by ground observations from NGTS, MEarth, LCOGT, and ASTEP.

With a radius of about 1.7 Earth radii, TOI-836 b is around 4.5 times more massive than the Earth, resulting in a density of 5.02 grams per cubic centimeter. According to experts, the not-so-distant exoplanet makes one orbit around its host star every 3,81 days, and it does so at a distance of around 0.0042 AU from it. Moreover, experts estimate that its equilibrium temperature is 871 K.

As a result, TOI-836 b can be referred to as a so-called “super-Earth” due to its parameters.

Planets with a mass greater than Earth, but less than Neptune, are called super-Earths. As well as being used as a term to describe planets larger than Earth, “super-Earths” are also used to describe planets that are smaller than the so-called mini-Neptunes (with a radius of two to four Earth radiuses).

“Mini-Neptune” TOI-836 c is approximately 2.6 times larger and 9.6 times more massive than Earth. As a result, it has a density of 3.06 grams per cubic centimeter. There is a 0.0075 AU separation between the planet and its parent star, and its orbital period is 8.6 days. The equilibrium temperature of the planet was estimated at 665 K.

Estimated to be approximately thirty-three percent smaller and less massive than the sun, TOI-836 is a 5.4-billion-year-old K-dwarf. With a temperature effective of 4,552 K, it has a metallicity of -0.284.

Observations of TOI-836 c show significant transit timing variations, which might indicate a third non-transiting planet in the system.

However, no transits of a third planet were found in the astronomers’ current photometry data, nor was there any indication of an additional periodic signal.