Astronomers Detect Water Hints on Exoplanet GJ 486 b, Raising Questions about Rocky Planets in Red Dwarf Systems
New Delhi : Astronomers have made an intriguing discovery about the exoplanet GJ 486 b. This rocky world, similar to Earth, is approximately 30 percent larger and three times more massive. It closely orbits a red dwarf star, completing a "year" in just 1.5 Earth days. Although GJ 486 b falls outside the habitable zone, where conditions for life are favorable, the James Webb Space Telescope has detected hints of water in its system.
The Space Telescope Science Institute (STScI) estimates that due to its close proximity to the star, GJ 486 b's surface temperature reaches around 430 degrees Celsius. Despite this extreme heat, the James Webb Space Telescope has identified indications of water vapor in the planet's vicinity. The source of this water vapor remains uncertain, as further observations are necessary to determine if GJ 486 b possesses an atmosphere at all.
Should the planet indeed possess an atmosphere, the water vapor would need to be continuously replenished, given the potential loss caused by the star's radiation. Another plausible explanation is that the detected water vapor originates from the outer layer of GJ 486 b's relatively cooler host star. To shed light on this matter, additional observations with the James Webb Space Telescope are required to assist astronomers in unraveling this intriguing question.
One important query in the field of astronomy is whether a rocky planet can maintain an atmosphere in the challenging vicinity of a red dwarf star. Red dwarf stars, also known as M-dwarfs, are believed to be the most abundant type of star in the universe. Smithsonian Magazine reports that they are relatively small, only slightly larger than gas giant planets. Furthermore, red dwarf stars possess low mass and temperature compared to other stars. The smallest red dwarfs have a mass of only about 80 times that of Jupiter, while our Sun is approximately 1,000 times more massive.
Red dwarf stars also emit relatively cooler temperatures, potentially allowing planets in close orbits to maintain liquid water. However, these stars are known for their high activity, particularly during their early stages. They emit significant amounts of ultraviolet and X-ray radiation, which could potentially strip away a planetary atmosphere.
Therefore, understanding whether a rocky planet can maintain or even reestablish an atmosphere in the vicinity of a red dwarf star is a crucial question for astronomers. GJ 486 b serves as a valuable subject for investigating this inquiry. The findings regarding the presence of water on this planet have been accepted for publication in the Astrophysical Journal Letters, documenting an exciting advancement in our understanding of exoplanetary systems.