Planetologists have discovered the smallest known exoplanet, which was discovered water vapor. A planet that is 124 light years away from Earth resembles Neptune in mass. Analyzes and observations have shown that in addition to the presence of water vapor, there is a surprisingly clear sky on the celestial body. The fact is that usually small exoplanets are usually covered by clouds throughout the atmosphere.
The lead author of the new study, Jonathan Fraine of the University of Maryland, reports that clear sky is in itself a unique feature for an exoplanet. He and his colleagues described the celestial body, codenamed HAT-P-11b, in an article in the journal Nature.
Astronomers for a long time tried to find a planet resembling Earth by mass, density of the atmosphere or weather conditions, but usually the clouds did not allow us to study distant worlds in detail. It turned out that HAT-P-11b is an unusual case. Frein’s team used the Hubble and Spitzer space telescopes to study the transits of the planet on the disk of their own luminary.
The blackouts caused by the passage of the world to the face of the parent star allowed not only determining its mass, but also conducting a spectral analysis of the chemical composition of the atmosphere. In total, scientists managed to twice “consider” the planet. Observations have shown that hydrogen and oxygen in the HAT-P-11b atmosphere manifests itself at specific wavelengths of light. Thus, planetologists realized that there was water vapor on the planet, rising to the high layers of the atmosphere.
To the surprise of scientists, the level of the signal indicated that there are practically no clots of clouds in these same layers. At least, the data of the Hubble, which, however, is not able to look even deeper into the atmosphere of HAT-P-11b, allow us to judge this. “However, clouds may be present closer to the surface of the planet.
If the pilots flew across the sky of this world, they would probably see cumulus clouds beneath themselves and a clear sky from above, ”explains Frain. According to the researchers, the unusual conditions on the exoplanet will help determine in the future exactly how it looks. According to the leading hypotheses, then HAT-P-11b could have a rocky-ice core, which slowly and gradually evaporated as the planet evolved.
HAT-P-11b is about four times the size of Earth, while its mass is 26 times greater. Such a high density may indicate other features of a distant world. In the near future, scientists plan to use data from space telescopes to find similar worlds. Perhaps as a result of this work it will be possible to learn more about the origin and nature of such exoplanets.