The American Space Agency (NASA) announced that the Hubble Space Telescope (Hubble) and the Subaru ground-based telescope in Hawaii have photographed a gas giant protoplanet, nine times the mass of Jupiter. It is the youngest protoplanet discovered to date.
It is a huge planetary "baby" still in the "womb" near the young star AB Aurigae, which has 2.5 times the mass of the Sun, is 60 times brighter and is only two million years old, compared to about 4.6 billion years old in our own solar system. The exoplanet and its star are located in the constellation of Hnecho, about 508 light-years from Earth.
More than 5,000 exoplanets have been confirmed to date and, according to NASA, AB Aur b is among the largest ever found. Its size is such that it could be considered not a planet but a brown dwarf, an intermediate category between a normal star and a planet.
Planets in the process of forming, i.e. protoplanets, have so far only been observed around another star. Almost all known exoplanets move within a distance from their star comparable to the Sun-Neptune distance. But AB Aur b orbits at three times the distance to Neptune and 93 times the Earth-Sun distance, according to Reuters.
The embryonic planet appears to evolve in a different way from that predicted by the previously prevailing theory of how gaseous giants like Jupiter form. The exoplanet in question, named AB Aur b, forms gradually through an unstable, intense and violent process rather than through a gradual accumulation of material, according to the researchers who made the announcement in the astronomy journal Nature Astronomy.
The planet under creation, located within a huge "parent" protoplanetary disk of dust and gas, leads scientists to conclude that there is more than one way to create Jupiter-type planets. "Nature is smart and can produce planets in several different ways," said lead researcher, astrophysicist Thane Curry of NASA's Ames Research Center and the Subaru Telescope in Hawaii.
The dominant theory of gaseous planet formation is that "from the bottom up through the gradual accretion of the original small rocky planetary core by the addition and welding together of more and more disk-matrix material and gas. The opposite is the "top-down" process, in which the original large disk around the parent star cools and gravity leads to its breakup into one or more protoplanetary pieces - something that seems to have happened with AB Aur b.
"The new discovery provides strong evidence that some gas giant planets can form through the mechanism of disk instability," said Alan Bosch of the Carnegie Institution of Science in Washington, D.C.
Source: APE-MPA
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