NASA has made a significant breakthrough by detecting water vapor in the atmosphere of a small exoplanet, GJ 9827d, using the Hubble Space Telescope. This exoplanet, roughly twice the size of Earth, is situated in the constellation Pisces, orbiting a red dwarf star named GJ 9827, located 97 light years away.
Discovered by NASA’s Kepler Space Telescope in 2017, GJ 9827d has a scorching temperature of 800 degrees Fahrenheit, akin to Venus. It completes an orbit around its host star every 6.2 days. The findings suggest the possibility of planets with water-rich atmospheres beyond our solar system.
The breakthrough allows scientists to directly confirm the existence of planets with water-rich atmospheres around distant stars. The team, led by Bjorn Benneke from the University of Montreal’s Trottier Institute for Research on Exoplanets, sees this as a crucial step toward understanding the prevalence and diversity of atmospheres on rocky planets.
GJ 9827d presents two potential scenarios. It could retain a hydrogen-rich envelope with water, resembling a mini-Neptune. Alternatively, it might resemble a warmer version of Jupiter’s moon Europa, with a composition of half water and half rock.
The observational data was gathered over three years, during 11 transits of GJ 9827d in front of its host star. The Hubble program detected the spectral signature of water molecules in the planet’s atmosphere during these transits.
Thomas Greene, an astrophysicist at NASA’s Ames Research Center, emphasizes the importance of observing water as a gateway to discovering more about planets. The current focus is on comprehensively understanding a planet’s elemental inventory, enabling comparisons with its host star and providing insights into its formation.
