Hubble Telescope Detects Water Vapor in Distant Planet’s Atmosphere

The discovery of an exoplanet named GJ 9827d, which is about twice the size of Earth and located 97 light-years away, has intrigued astronomers due to the presence of water vapor in its atmosphere. This significant finding was made using the Hubble Space Telescope, an older but still highly effective piece of technology, even with the newer James Webb Space Telescope in operation.

Orbiting a red dwarf star known as GJ 9827, the exoplanet completes a full orbit in just 6.2 days, meaning its ‘year’ is shorter than a week by Earth’s standards. This recent discovery marks the first time astronomers can directly indicate the existence of planets with water-rich atmospheres outside our solar system. Björn Benneke from the Trottier Institute for Research on Exoplanets at Université de Montréal, part of the research team, highlighted the significance of this discovery for understanding the variety and frequency of atmospheres on rocky planets.

Though GJ 9827d was initially discovered in 2017, the detection of water in its atmosphere is a novel finding. Laura Kreidberg from the Max Planck Institute for Astronomy in Heidelberg regards the presence of water on such a small planet as a groundbreaking step towards identifying Earth-like worlds.

However, it remains uncertain if the water forms part of a hydrogen-rich ‘puffy’ atmosphere or if the planet itself is abundant in water. According to Pierre-Alexis Roy from the Trottier Institute, the research aimed to identify water vapor specifically, whether as a dominant component or a minor presence in a hydrogen-dominated atmosphere. This discovery is pivotal as it represents the first time the atmosphere of such a small planet has been directly detected, moving closer to understanding planets with atmospheres similar to Venus, which is dominated by carbon dioxide.

While the high surface temperature of GJ 9827d, similar to Venus at around 800 degrees Fahrenheit, makes it challenging to determine the likelihood of life, the presence of water leads to the hopeful notion that where there’s water, life could potentially exist. This finding offers a comforting perspective for those pondering the profound question of whether we are alone in the universe.