The hunt for an Earth-like planet shielded with a protective atmosphere has so far eluded scientists, but a new detection by the
Astronomers are taking a closer look at
Despite its being so close to its host star and having a scorching-hot temperature of about 800 degrees Fahrenheit, the planet shows signs of having water vapor — a hint that the alien world may have an atmosphere swaddling the planet.
“Water vapor in an atmosphere on a hot rocky planet would represent a major breakthrough for exoplanet science,” said Kevin Stevenson, the principal investigator of the study from the Johns Hopkins University Applied Physics Laboratory, in
Why do we need an atmosphere?
Water vapor has been discovered on
Perhaps surprisingly, though, another possible explanation for the vapor detected by Webb is that water is coming from the outer layer of the nearby red dwarf star — cooler than the sun — not from the planet at all. Scientists will need more observations to determine if the exoplanet indeed has an atmosphere and how much water is present.
Credit: NASA / ESA / CSA / Joseph Olmsted (STScI)
Even the sun sometimes has water vapor in sunspots because these areas are much cooler compared to the surrounding surface of the star. Given that the recently found exoplanet’s star is much cooler than the sun, Webb researchers say it’s even more plausible water vapor would concentrate within its starspots. That means no one yet knows whether the star is mimicking the signal they’d see from a planet’s atmosphere.
“Water vapor in an atmosphere on a hot rocky planet would represent a major breakthrough for exoplanet science.”
The new Webb research
Credit: NASA / ESA / G. Bacon (STScI)
How does Webb study exoplanets?
Webb, a collaboration of NASA, the European Space Agency, and the Canadian Space Agency, is the most powerful infrared telescope in
The Webb researchers used a technique called
After observing two instances of the planet crossing in front of its star, the researchers used three different methods to analyze the data. All were consistent in showing a strong likelihood for a water vapor signal,
“We didn’t observe evidence of the planet crossing any starspots during the transits. But that doesn’t mean that there aren’t spots elsewhere on the star,” said Ryan MacDonald, a co-author from the University of Michigan in Ann Arbor,
If you’re thinking this means Earthlings have found a Plan B planet, don’t get too excited: Scientists say GJ 486b appears to be too close to its star to be habitable. But if it does have an atmosphere, they hope to learn whether such a rocky planet could maintain the protective cocoon, even as its super-close star cooks it away with heat and solar radiation.
How could such a planet replenish its atmosphere?
One theory suggests volcanoes spewing steam from deep within the planet.