For the first time, scientists have detected “bright” water molecules around a planet outside our Solar System. This is an incredible find, as it could give us more information about hot jupiters, a mysterious type of Jupiter-like gas giants that are not found within our solar neighborhood.
Before we get carried away with excitement, it is important to note that hot jupiters like the newly discovered WASP-121b, which is about 900 light-years distant from Earth , are not likely to support life, given their scorching atmosphere.
However, understanding more about their atmospheres is relevant in determining the physical and chemical conditions that make up extraterrestrial worlds.
“This result is exciting because it shows that a common feature of most atmospheres in our Solar System – a warm stratosphere – can also be found in exoplanet atmospheres, ” says Mark Marley of NASA’s Ames Research Center.
Scientists detected glowing water molecules in WASP-121b’s atmosphere using NASA’s Hubble Space Telescope, with spectroscopic analysis showing water molecules emitting infrared radiation as they lose energy due to increased heat in the extraordinarily hot stratosphere of the planet. We are not short, as we are talking about 2,500 ºC in the upper atmosphere.
“When it comes to distant exoplanets, which we cannot see in the same detail as other planets in our own Solar System, we have to rely on current techniques to reveal their structure. WASP-121b’s stratosphere is so hot that it can make them glow. water vapor, which is the basis of our analysis, “explains Drake Deming of the University of Maryland.
Thus, although we know that the presence of water is a sign that may offer an opportunity for life on distant worlds, it is unlikely to be the case for WASP-121b. T his exoplanet is 1.2 times the mass of Jupiter and its radius is also greater, but in at least one respect it is very different from the planet we know.
Unlike Jupiter, which orbits the Sun once every 12 years, WASP-121b’s orbit relative to its star is 1.3 days. That intense proximity explains why it is not a potentially habitable planet and if it were even closer to its star, its star’s gravity would inevitably tear it apart.
“We have measured a strong increase in the temperature of the WASP-121b atmosphere at higher altitudes, but we still do not know what is causing this dramatic heating. We hope to address this mystery with future observations at other wavelengths” clarifies Nikolay Nikolov of the Exeter University.
It is thus the first step in a long way but at last we are before the discovery of bright water molecules as the clearest sign for an exoplanet with a stratosphere.
Referencia: Universidad de Exeter. Universidad de Maryland. ‘An ultrahot gas-giant exoplanet with a stratosphere’. Nature. 2017. doi:10.1038/nature23266
