The GJ 436b may look like a super comet with a long tail but it is actually a planet located 33 times closer to its star compared to the Earth orbiting the sun.
The close proximity of the Neptune-like planet (in terms of size) to its star is the reason why its atmosphere continues to thin and form a tail just like a comet. Now, scientists say that the Earth might have undergone the same process and looked like the GJ 436b in the past.
The team of astronomers, led by David Ehrenreich from the Observatory of the University of Geneva in Switzerland, used the Hubble Space Telescope by the National Aeronautics Space Administration (NASA) to discover the large hydrogen cloud tailing the GJ 436b called "The Behemoth." The planet is 50 times bigger than its parent star and the hydrogen component evaporates due to the intense heat and radiation from the star.
The team of researchers think that the vast cloud of gas enveloping the planet does not evaporate too quickly with the amount of heat and radiation that its red dwarf star, which is relatively cool, possesses. This is the reason why the cloud of gas continues to stay.
The process of atmospheric evaporation in hydrogen-encased planets may leave behind hot, solid cores and the end products may be comparable to the size of the Earth, thus it is termed Hot-Super Earths.
According to scientists, the mechanisms of evaporations observed in this planet may suggest that this might be the process that the Earth and the solar system went through in the past. Earth used to have a hydrogen-filled atmosphere that was depleted more than 100 to 500 million years ago. If that is the case, then the Earth might have looked like a comet in the distant past as well.
The rate at which the atmosphere of the GJ 436b is evaporating is not a cause of threat for the planet's existence right now, but because the scientists are very well aware that the red, dwarf star was more active in the past, the atmospheric evaporation may be more rapid in its initial years, Ehrenreich believes.
The findings may also provide valuable insight into the continuous search for planets conducive for living, says Vincent Bourrier, study co-author. This is because the scientists were also able to identify hydrogen components that evaporate on minimally hotter terrestrial planets, something that could be detected in the oceans of the Earth.
The discovery of "The Behemoth" sheds new light on the atmosphere of Neptune-sized planets and Hot-Super Earths. In the future, the team hopes to discover more planets of this kind.
