2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
The TESS Space Telescope has discovered its first Earth-like planet, orbiting a star 53 light-years from the Sun. The planet is almost 2.5 times heavier than the Earth and slightly smaller in size, and a year on it lasts 7, 8 Earth days. Article published in Astrophysical Journal Letters
The TESS space telescope was launched into space in April 2018 and is designed to search for exoplanets using the transit photometry method - it tracks the change in the brightness of a star as a planet passes through its disk. The main targets of the telescope are bright stars and their systems at a distance of 30 to 300 light years from Earth. Exoplanet candidates become targets of other observatories (both ground-based and orbiting), which are engaged in further detailed study of objects. In total, in the first six months of its operation, the telescope detected more than 280 candidates for exoplanets, of which eight were confirmed. In addition, he observed six Type Ia supernova explosions.
In a new work, a group of astronomers led by Diana Dragomir (Diana Dragomir) report the discovery of two exoplanets (HD 21749b and HD 21749c) in the K-dwarf system, the mass of which is 0.73 solar masses, and the radius is 0.69 solar radius. The system is estimated at 3.8 billion years old and lies about 53 light-years from Earth in the constellation Grid. The exoplanets were found by analyzing the data collected by TESS from July 25 to October 14, 2018, confirmed by the HARPS echelle spectrograph installed on the telescope at the La Silla Observatory and the PFS (Planet Finder Spectrograph) spectrograph installed on one of the Magellanic telescopes.
HD21749b is classified as sub-Neptune and has the longest orbital period of the three planets discovered so far by the telescope, which is 36 days. The mass of the exoplanet is about 22.7 Earth masses, and the radius is 2.61 Earth masses. It is assumed that it may have a dense atmosphere, the equilibrium temperature of the planet is estimated at 423 Kelvin. Exoplanet HD 21749с has a mass of less than 3.7 Earth masses (calculated value is 2.5 Earth masses) and a radius of 0.89 Earth's radius, making it the first Earth-like planet discovered by TESS. It makes one revolution around the star HD 21749c in 7, 8 days.
Both exoplanets are difficult enough targets for follow-up observations. For researchers to be able to compare the properties (mass, volume and estimated composition) of HD 21749c with Earth, long-term observations are required to obtain sufficiently accurate parameters of the exoplanet. In the case of HD21749b, scientists doubt that it will be suitable as a target for the future James Webb Space Telescope, however, it can be observed using spectrographs installed on large ground-based telescopes such as ESPRESSO.
Earlier we talked about the four-year time-lapse of Beta Pictoris b, why all the planets of the TRAPPIST-1 system were recognized as Earth-like and how a red dwarf with a “monster” planet did not fit into the expectations of astronomers.
