A team of astronomers from NASA and the University of Exeter (United Kingdom) has discovered, thanks to data from the Hubble and Spitzer space telescopes, an exoplanet very similar to Neptune – although warmer – with an atmosphere of hydrogen and helium in the one that has found water.
It is the exoplanet HAT-P-26b , which has a similar size and is about 437 light years distant from Earth, orbiting a star slightly smaller than our Sun.
The results of the observations have revealed that the atmosphere of this planet consists mainly of hydrogen and helium clouds, with obvious signs of the presence of water . The funny thing is that its amount of heavy metals is less than expected; This will help us to understand how other planetary systems originated and to decide with what probability a solar system like ours could have been formed.
“H2O is one of the most abundant molecules in the universe and we think it is well mixed in the gaseous atmosphere of HAT-P-26b and other giant exoplanets like it,” explains Hannah R. Wakeford, leader of the work.
Despite the fact that a great diversity of planets that are not part of our solar system have been discovered, the information about their atmospheres is quite meager , so knowing new data about their atmospheric composition can provide us with important clues about how they formed. these extrasolar planets.
‘What is important about this water is that it gives us clues about how the planet was formed. In the case of HAT-P-26b, it turns out that its metallicity is lower than expected . In our solar system, the metallicity of Jupiter is between two and five times that of the Sun, and that of Saturn about ten times more. However, Uranus and Neptune contain more heavy elements, and present metallicities that exceed more than a hundred times that of our star ‘, clarifies Wakeford.
From the data it can be inferred that ‘the planets of less mass have higher metallicity in their atmosphere and other’ Neptunes’ discovered with water in their atmosphere –such as the recently discovered one– fit in with this trend; however, the atmosphere of HAT-P-26b has a metallicity closer to Jupiter, about four or five times that of the Sun ‘.
The explanation? Scientists believe that the planet formed at a later stage, perhaps near its star, or both at the same time. ‘This is the first time that we have seen this kind of diversity in the atmospheres of these exoplanets. It is important to understand how other planetary systems originated to determine how likely it is that a solar system like ours will form, ‘says Wakeford.
The study has been published in the journal Science.
