Hubble Detects Water Vapor on Small Exoplanet GJ 9827d

Discovery Marks First Detection of Water on a Planet of This Size, Opening New Avenues for Exoplanetary Research

NASA's Hubble Space Telescope has detected water vapor in the atmosphere of a small exoplanet named GJ 9827d, marking the smallest exoplanet where water has been detected.
The planet, approximately twice the size of Earth and located 97 light-years away, could serve as an example of potential water-rich worlds elsewhere in our galaxy.
Despite the presence of water, the planet's high temperature of 800 degrees Fahrenheit makes it an inhospitable, steamy world.
Researchers are considering two possibilities for the planet's atmosphere: it could be a hydrogen-rich atmosphere laced with water, making it a mini-Neptune, or it could be a warmer version of Jupiter's moon Europa, which has twice as much water as Earth beneath its crust.
The discovery opens the door for future study of these types of planets by the James Webb Space Telescope, which can conduct more detailed infrared observations.