Astronomers using NASA’s Hubble Space Telescope have detected water molecules in the atmosphere of a small, blazing-hot exoplanet 97 light-years away from Earth.
The planet, called GJ 9827d, is about twice the diameter of Earth and may be an example of potential planets with water-rich atmospheres elsewhere in our galaxy.
“This will be the first time that we can show directly through atmospheric detection that these planets with water-rich atmospheres can exist around other stars,” said team member Björn Beneke of the Trottier Institute for Research on Exoplanets at the Université de Montréal. ” “This is an important step toward determining the extent and diversity of atmospheres on rocky planets.”
“Water on such a small planet is a historic discovery,” said co-principal investigator Laura Kreidberg of the Max Planck Institute for Astronomy in Heidelberg, Germany. “This brings us closer than ever to characterizing an Earth-like world.”
Water is essential for life, but any form of life is unlikely on this exoplanet due to its extreme temperatures, which would vaporize the water-rich atmosphere. However, astronomers have yet to discover the truth about this unusual atmosphere of the world.
Currently, the research team cannot tell whether Hubble picked up traces of water vapour within an inflated, hydrogen-rich atmosphere or whether the planet had a water-rich atmosphere because the host star has replaced GJ 9827’s original hydrogen and helium atmosphere. had evaporated.
“Our observing program, led by principal investigator Ian Crossfield of the University of Kansas in Lawrence, Kansas, was specifically designed not only to detect molecules in the planet’s atmosphere but specifically to look for water vapour.
No “The results will also be exciting, whether water vapor is the dominant or just a minor species in hydrogen-dominated atmospheres,” said lead author of the Science paper, Pierre-Alexis Roy of the Trottier Institute for Research on Exoplanets at the Université de Montréal.
“Until now, we have not been able to directly detect the atmosphere of such a small planet. And now we are slowly getting into this system,” Beneke said. “At some point, as we study smaller planets, there should be a transition where there is no more hydrogen on these smaller worlds, and their atmospheres are more like those of Venus (which is dominated by carbon dioxide).”
Because the planet is as hot as Venus, at 800 degrees Fahrenheit, it would certainly be an inhospitable, steamy world if the atmosphere were primarily water vapour, NASA said in a release.
At present the team has two possibilities left. One scenario is that the planet is still clinging to a hydrogen-rich atmosphere containing water, making it a mini-Neptune.
Alternatively, it could be a hotter version of Jupiter’s moon Europa, which has twice as much water beneath its crust as Earth.” The planet GJ 9827d could be half water, half rock. And it would have a lot of water vapour at the top, along with some smaller Rock body,” Benecke said.