TESS target files of Sectors 14, 20, 21, and 26 were observed by TOI-2257. The red shaded regions are where the photometry was taken. The TOI-2257 is shown as red circles in the Gaia DR2 catalog, but all of the sources are up to 6 magnitudes. The symbol size scales with the magnitude contrast. The star is relatively isolated and there is a small amount of contamination from outside sources. Credit: DOI: 10.1051/0004-6361/
A research team led by the University of Bern has discovered a sub-Neptune exoplanet. The discovery was made thanks to observations made by the SAINT-EX observatory. The Center for Space and Habitability is part of the SAINT-EX consortium and is located at the University of Bern.
Our Sun is much cooler than red dwarfs. Liquid water can be found on planets much closer to the star than in our solar system. The closer a planet is to its star, the higher the chance that it can be detected.
A team of researchers led by Dr. Nicole Schanche of the Center for Space and Habitability of the University of Bern have discovered a planet around a red dwarf. Nicole Schanche is a member of the National Center of Competence in Research PlanetS, which is a partnership between the University of Bern and the University of Geneva.
A special telescope is part of the solution.
There are planets that are far from our solar system that can't be seen with a telescope. The transit method is one way to detect such planets. This involves using telescopes to look for dips in the star's brightness when planets pass in front of it. The dips in the star's brightness give researchers precise measurement of the planet's orbital period around the star, and the depth of the transit allows them to determine the planet's diameter. The planet density can be calculated using estimates from other methods.
The data from NASA's TESS space telescope initially identified Planet TOI-2257 b. It was not clear if the decrease in brightness could be explained by the transit of a planet with an average age of 36 days.
There was no evidence that a planet with a 59-day orbital period was causing the star's brightness to fall. Nicole Schanche said they wanted to find out if the 35-day period could be possible.
The SAINT-EX telescope is designed to study red dwarfs and their planets in more detail. SAINT-EX stands for Search and character IsatioN of transiting planets. The project was named after the famous writer, poet and aviator,Antoine de Saint-Exupéry. SAINT-EX was able to confirm the exoplanet's exact orbital period, which was 35 days, by observing a partial transit of TOI-2257 b. "Another 35 days later, SAINT-EX was able to observe the entire transit, which gave us even more information about the properties of the system," says co-author Robert Wells from the CSH, who was involved in the data processing.
A planet with an irregular path.
Conditions favorable for the emergence of life could exist if TOI-2257 b were to go around the host star at a distance where liquid water is possible. Thehabitable zone near a small red dwarf star makes it easier to study because they have shorter orbital periods. The TOI-2257 b is 2.2 times larger than Earth and has high atmospheric pressure that is not good for life.
Nicole Schanche says that TOI-2257 b does not have a circular, concentric circle. It is the most eccentric planet ever found. Nicole Schanche says that this is bad news. The planet's average temperature is comfortable, but it varies from -80C to about 100C depending on where in the world it is. There is a chance that a giant planet is in the system and is affecting the TOI 2 257 b. Further observations of the star's radial velocity will help confirm the star's eccentricity and help find additional planets that could not be seen in transit.
A candidate for observation.
The James Webb Space Telescope will change the way research is done into exoplanet atmospheres. A transmission spectroscopy metric was developed to rate different system properties in order to prioritize good candidates for observations. One of the most attractive sub-Neptune targets is TOI-2257 b. Nicole Schanche says that the planet could be studied for signs of water in the atmosphere.
The TOI-2257 b is a highly eccentric long-period sub-Neptune transiting a nearby M dwarf. There is a book titled "1051/0004-6361/202142280".
The journal has information about astronomy and astrophysics.
The exoplanet was discovered on January 7, 2022.
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