Astronomers studying the rocky exoplanet GJ 486 b, located 26 light-years away in the constellation Virgo, have detected potential hints of water vapor using NASA’s James Webb Space Telescope. GJ 486 b, which is about 30% larger and three times more massive than Earth, closely orbits a red dwarf star every 1.5 days. Its high surface temperature of approximately 800 degrees Fahrenheit means it lies outside the habitable zone. The water vapor detected could indicate an atmosphere around the planet, but researchers caution it could also originate from the star itself, particularly from cooler starspots on its surface.
The study’s lead author, Sarah Moran, highlighted the uncertainty in determining the source of the water signal, emphasizing that while a planetary atmosphere would be a major breakthrough in exoplanet science, evidence suggesting the star as the source cannot be overlooked. Observations from different Webb instruments, including the Mid-Infrared Instrument and Near-Infrared Imager, are planned to differentiate between these scenarios. These findings have significant implications for understanding whether rocky planets can maintain, or regenerate, atmospheres in harsh environments close to red dwarf stars. The study is accepted for publication in The Astrophysical Journal Letters.
