The Hubble Telescope, which operates as a space radar, is said to have discovered the existence of a planet that contains water in its atmosphere.
This planet is called GJ 9827 and its diameter is twice that of Earth. The star GJ 9827 is located 96 light-years from Earth, in the constellation Pisces, and is surrounded by at least three exoplanets discovered in 2017 by the Kepler telescope. Of these three exoplanets, GJ 9827 is the largest and orbits its star in just 6,201 days. Its surface temperature is estimated at approximately 425 degrees Celsius.
So astronomers spent several hours observing it, initially using the Planet Finder spectrometer of the Magellan II telescope, installed in Chile. They then used the Hubble Telescope, which was able to record 11 transits, when the planet passed in front of its star and its light was filtered by the planet's atmosphere.
The planet is still a mystery
Thus, analyzes of light spectra allowed scientists to determine the presence of water vapor in the atmosphere of planet GJ 9827: “Until now, we have not been able to directly detect the atmosphere of such a small planet. We are slowly entering this system now.Björn Beneke of the University of Montreal explained.
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However, there are still some mysteries to be discovered regarding this planet, especially its status. It could be a Neptune-like planet, with an atmosphere containing a lot of hydrogen and water. But it could also be a “hot version” of Jupiter's moon, called Europa, which harbors an ocean beneath its frozen crust.
To get to the heart of this question, but also to learn more about the planet's formation, NASA will certainly use the James Webb Telescope.
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