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August 17, 2019: TESS Telescope Discovers 3 New Alien Worlds

TESS

The Transiting Exoplanet Survey Satellite (TESS) is a space telescope for NASA's Explorers program. It is designed to search for exoplanets using the transit method. It was launched on April 18, 2018 atop a Falcon 9 rocket. During its 2-year primary mission, it is expected to find more than 20,000 transiting exoplanets. The TESS has discovered a set of 3 worlds orbiting a peaceful star located a mere 73 light-years from Earth in the constellation of Pictor. The exoplanets are among the smallest and closest known. This discovery helps scientists to understand how different-sized planets are formed. The search for alien life also continues.

People can use TESS to study the mass, size, density and orbit of a large number of small planets. TESS provides interesting information for further characterization by the James Webb Space Telescope. Other large ground-based and space-based telescopes also use this information. Previous sky surveys with ground-based telescopes have mostly found giant exoplanets. TESS will find many small planets around the nearest stars in the sky.

Apogee and perigee refer to the distance from the Earth to the moon. Apogee is the farthest point from the earth. Perigee is the closest point to the earth and it is in this stage that the moon appears larger. TESS uses a novel highly-elliptical (egg shaped) orbit around the Earth with an apogee approximately at the distance of the Moon and a perigee of 108,000 km. TESS orbits Earth twice during the time the Moon orbits once, a 2:1 resonance with the Moon. The orbit is expected to remain stable for a minimum of 10 years.

The TESS telescope has 4 identical cameras that combine to observe a part of the night sky spanning 24 x 90 degrees. The data showed that the 3 worlds were orbiting the nearby star TOI 270. The name of the star means it was the 270th object of interest that TESS has identified since it began science operations. The 3 new found worlds orbit around an M-dwarf star that has already experienced its young energetic phase. This star now shines with a steady light. Planet TOI 270 b, the innermost world, is thought to be a rocky super-Earth with a radius roughly 1.25 times that of our planet. The outermost two planets, TOI 270 c and d, are likely gas-dominated sub-Neptune worlds. Planet c, which occupies the middle orbit of the 3 worlds has a radius equivalent to 2.4 times that of Earth, while Planet d is slightly smaller.

As many people know, the Moon always shows the same side to the Earth. Scientists believe that the 3 new found worlds always present the same side to their parent star. The 2 Neptune-like exoplanets are similar in terms of radius. Their size is kind of intermediate. TOI 270 is different from our Sun, because the Sun has no intermediate planets orbiting it. Our solar system has smaller rocky planets such as Mercury and Venus, and the huge gassy giants Jupiter, Saturn and Neptune. TOI 270 may be capable of hosting life.

Scientists initially believed that the planet 270 d orbited within the habitable zone of its parent star. This would be a region of space where liquid water could theoretically exist on a planet's surface. However, further analysis showed that the exoplanet's atmosphere was likely too dense. This would have triggered a runaway greenhouse effect, which would have rendered the surface too hot to sustain life. The upper atmosphere may have a temperature that could allow extremophile (microorganism, especially an archaean, that lives in conditions of extreme temperature, acidity, alkalinity, or chemical concentration) organisms to exist. Also, there could be more worlds orbiting TOI-270 that have not been discovered yet.

Planet TOI 270 b is the innermost planet. It has an orbital period of roughly 3 Earth-days. Planet c takes 5 days to orbit its star. Planet d takes 11 days. The 3 alien worlds orbit in a pattern known to astronomers as a "resonant chain." Periodically, as the exoplanets move through their orbits, they line up with each other relative to their star, and their gravitational forces influence, or resonate with one another. The planets line up like pearls on a string. There could be another planet that lines up, also. Maximilian GŁnther is a postdoc in MIT's Kavli Institute for Astrophysics and Space Research and lead author of the study detailing the discovery. In the future, the researchers plan to bring more powerful telescopes for TOI 270, including the future James Webb Space Telescope.