Recently published in Aston OMY & amp； In a study of Astophysics, researchers led by Dr. Nicole Schanche from the Center for Space and Livability of CSH Bourne University reported that they had discovered an exoplanet TOI-2257 b orbiting a nearby red dwarf. Nicole Schanche is also a member of the National Center for Planetary Research, which is jointly managed by the University of Bern and the University of Geneva.
A special telescope is part of the solution.
Exoplanets far away from our solar system cannot be directly observed by telescopes-they are too small and reflect too little light. However, one way to detect such planets is the transit method. This includes using a telescope to detect the decrease in brightness of a star when a planet passes in front of it. Repeated observation of the brightness decrease of the star can accurately measure the orbital period of the planet around the star, and the depth of transit allows researchers to determine the diameter of the planet. When combined with the planet mass estimation from other methods, the planet density can be calculated.
TOI-2257 b planet was originally identified by data from NASA's transit exoplanet survey satellite TESS Space Telescope. This small star has been observed for four months, but the observation interval means that it is not clear whether the decrease in brightness can be explained by planetary transits with orbits of 176, 88, 59, 44 or 35 days.
After observing the star with the global telescope of the Brece Observatory in Lasquin, the researchers ruled out the possibility that a planet with an orbital period of 59 days would lead to a decrease in brightness. "Next, we want to find out whether a 35-day orbital period is possible," Nicole Sanchi pointed out.
The SAINT-EX telescope in Mexico cooperates with CSH and NCCR Aircraft Company to study red dwarfs and their planets in more detail. SAINT-EX is the search and characterization of exoplanets in transit system. This project was named in memory of Antoine de Saint-Exupé ry, a famous writer, poet and pilot. SAINT-EX observed the partial transit of TOI-2257 b and was able to confirm the exact orbital period of this exoplanet around its star, that is, 35 days. "After another 35 days, SAINT-EX was able to observe the whole transit, which provided us with more information about the properties of the system," said robert wells, co-author of the paper from CSH, who participated in the data processing.
Temperate planets with irregular orbits
TOI-2257 b orbits the main star with an orbital period of 35 days. At this distance, there may be liquid water on the planet, so there may be conditions conducive to life. Planets in the so-called "livable zone" near the little red dwarf are easier to study, because their orbital periods are shorter, so they can be observed more frequently. The radius of TOI-2257 b (2.2 times larger than that of the Earth) indicates that this planet is quite gaseous, with high atmospheric pressure, which is not conducive to the existence of life.
"We found that TOI-2257 b has no circular and concentric orbits," Nicole Sanchi pointed out. "In fact, it is the weirdest planet ever discovered orbiting a cold star. This is bad news in terms of potential habitability. Although the average temperature of this planet is comfortable, its temperature ranges from -80 to about 100, depending on the position of this planet in its orbit, whether it is far from or close to the star. " One possible explanation for this surprising orbit is that a huge planet lurks further in the system, which disturbs the orbit of TOI 2257 b. The observation of further measuring the radial velocity of the star will help to confirm the eccentricity and find possible additional planets that cannot be observed during the transit.
Candidates observed using JWST
The James Webb Space Telescope (JWST), successfully launched on February 25th, 65438, will completely change the research on the atmosphere of exoplanets. In order to give priority to the excellent candidates observed by JWST, the researchers developed the Transmission Spectrum Index (TSM) to evaluate different system properties. TOI-2257 b is well positioned in TSM and is one of the most attractive targets under Neptune. Nicole Sanchi concluded: "In particular, we can study the characteristic signs of this planet, such as water vapor in the atmosphere."