NASA telescopes reveal atmosphere of unique hybrid exoplanets
For the first time, two NASA space telescopes have identified detailed chemical ‘fingerprint’ of a planet between the sizes of Earth and Neptune. These planets are common around other stars, but have not been found so far in our own solar system.
The exoplanet, Gliese 3470 B also known as GJ 3470 b, has a rocky core like Earth, but is surrounded by a thick layer of gas made of hydrogen and helium, which makes it a rare combination in our solar system. The exoplanet weighs 12.6 Earth masses.
This is a big discovery from the planet formation perspective. The planet orbits very close to the star and is much small in size than Jupiter.
Bjorn Benneke of the University of Montreal, Canada said, “For the first time we have a spectroscopic signature of such a world. We expect an atmosphere strongly enriched in heavier elements like oxygen and carbon which are forming abundant water vapour and methane gas, similar to what we see on Neptune. Instead, we found an atmosphere that is so poor in heavy elements that its composition resembles the hydrogen/helium rich composition of the sun.”
Other exoplanets called ‘hot Jupiters’ are thought to form far from their stars and overtime migrate much closer. But this seems to have formed just where it is today, said the researcher.