Hubble discovers water vapor in exoplanet’s atmosphere – 01/25/2024 – Science

The Hubble Telescope discovered water vapor on a planet more than 900 trillion kilometers away. This is the smallest planet outside the solar system where water has been found in the atmosphere, the American and European space agencies, NASA and ESA, reported this Thursday (25).

According to Laura Kreidberg, from the Max Planck Institute for Astronomy, in Germany, co-director of the research, finding water on such a small planet is an important discovery. “It brings us closer than ever to describing truly Earth-like worlds.”

The planet GJ 9827d, whose diameter is approximately twice that of Earth, lies in the constellation Pisces, 97 light-years away. Planets that lie outside the Solar System are called exoplanets.

It is believed to be a “mini-Neptune”, with an atmosphere rich in hydrogen and water, or a hotter version of Jupiter’s moon, Europa, which has twice as much water under its crust as Earth.

“GJ 9827d could be half water, half rock,” explained Björn Benneke of the University of Montreal, co-director of the research. “And there would be a lot of water vapor on top of a smaller rocky body.”

“Until now we have not been able to directly detect the atmosphere of such a small planet. And we are slowly getting there,” he said.

For three years, Hubble analyzed the wavelength of the colors in this planet’s atmosphere — when the light from the star around which it orbits is filtered through its atmosphere — and identified the presence of water molecules.

Although GJ 9827d has a water-rich atmosphere, its temperature of 425°C makes it uninhabitable.

The discovery paves the way for new studies of both this planet and others similar to it, especially using the James Webb space telescope. It can take high-resolution infrared images where scientists can look for other atmospheric molecules, such as carbon dioxide and methane.