The Alpha Centauri A star, located only four light years from the Earth, could house a giant gaseous planet and the James Webb Space Telescope It has provided the most solid tests of its existence.
The existence of such an exoplanet would offer the best opportunity to collect data on planetary systems other than ours, but it is very difficult observations to do even for the Webb.
The triple star system Alfa Centaurivisible only from the southern hemisphere of the earth, it is formed by binary starss Alfa Centauri A and Alfa Centauri Bboth similar to the sun, and the faint red dwarf star Next Centauri.
The latter houses three planets, but it is much more difficult to detect its existence in Alfa Centauri A and B, being very bright, being very close and moving quickly through the sky.
However, astronomers have found solid evidence of the existence of a giant planet that Orbit Alfa Centauri A, the third brightest star in the night sky.
If its existence is confirmed, The planet would be the closest to the Earth that orbits in the habitable zone of a star similar to the sunalthough being a gaseous giant could not house life as we know it.
The researchers believe that an approximate mass could have that of Saturn and orbital around Alfa Centauri A in an elliptical trajectory that varies between 1 and 2 times the distance between the sun and the earth.
The discovery, which has been accepted for publication in The Astrophysical Journal Letters, was achieved through several rounds of observation with James Webb, the first one now a year ago, for which the instruments of the telescope had to attenuate the light emitted by Alfa Centauri A and B.
A thorough analysis by the research team and an extensive computer modeling helped determine that the source seen in the webb image is probably a planet, and not a background object (such as a galaxy), an object in the foreground (an asteroid that passes) or another detector or image artifact.
The researchers made additional observations in April and February, but did not reveal any object similar to that identified in August 2024.
The team made multiple orbit simulations of that possible exoplanet and considered that “it is not surprising that nothing has been detected in the second and third round of observations with Webb”, according to a statement the European Space Agency (ESA).
“We discovered that, in half of the possible simulated orbits, the planet approached the star too much and would not have been visible to Webb or in February or in April 2025”Said researcher Aniket Sanghi, from the California Institute (USA).
The possible planet seen in the image of Webb taken from Alfa Centauri to “It would mark a new milestone in the efforts to obtain exoplanet images” and Of all those photographed directly “it would be the closest to their star seen so far.”
It would also be the “most similar in temperature and age to the giant planets of our solar system, and the closest to our home, the earth,” Sanghi said.
His mere existence in a two -star system very close to each other, “said the researcher,” we would question our understanding of how the planets survive and evolve in chaotic environments. “