Water, often cited as a harbinger of life wherever it is discovered, has been detected in the atmosphere of an exoplanet called GJ 9827d, fuelling interest and excitement about the possibilities of extraterrestrial life. This exoplanet, which is roughly double the size of Earth, is located 97 light-years away and completes one orbit around its star, designated GJ 9827, in merely 6.2 days, making its years much shorter compared to Earth’s.
Revealed through the efforts of astronomers using the Hubble Space Telescope, this discovery marks the first time water vapor has been detected directly on a planet of such a small size. The findings represent a considerable step towards understanding the variety of atmospheres that rocky planets beyond our solar system may possess. Though GJ 9827d was identified in 2017, the recent detection of water in its atmosphere has raised the prospect of it having water-rich conditions.
The scientific community, including team member Björn Benneke from the Trottier Institute for Research on Exoplanets at Université de Montréal, has heralded this as an essential milestone for determining how common and diverse atmospheres are on rocky exoplanets. Despite the excitement, it is too early to conclude if the planet has a ‘puffy hydrogen-rich atmosphere’ or is abundant in water. With a high surface temperature comparable to Venus at 800 degrees Fahrenheit, the planet might be too hot to support life as we know it, but as the old adage goes, ‘Life finds a way,’ and the presence of water always leaves room for speculation and hope about life’s existence.
Identified by NASA’s Kepler Space Telescope and lying in the constellation Pisces, this exoplanet’s atmosphere could either resemble a mini-Neptune or be akin to a warmer version of Jupiter’s moon Europa, with ample water vapor present. In their observations over three years, astronomers focused on the spectral fingerprint of water molecules during the 11 transits of the planet across its star. This careful analysis of water is part of a broader effort to understand the complete elemental makeup of exoplanets to shed light on their formation and the nature of planets outside our solar system.