Baby Jupiter's huge weight gain

**Oisín** · 01-07-2009, 02:49 PM

Baby Jupiter's huge weight gain

Jupiter would have grown fast in its infancy

The planet Jupiter must have gained mass fast during its infancy, according to astronomers.

It had to, because the material from which the planet formed disappeared in just a few million years.

After studying other stars, the US team came to the conclusion that gas giants like Jupiter must grow rapidly.

Details of the group's work were outlined at the 213th meeting of the American Astronomical Society (AAS), held in Long Beach, California.

Astronomers examined the five million-year-old star cluster NGC 2362 with Nasa's Spitzer Space Telescope.

Spitzer can detect the signatures of actively forming planets in infrared light.

The research team found that all stars with the mass of the Sun or greater have lost their "proto-planetary", or planet-forming, discs.

Only a few stars less massive than the Sun retain these discs of dust and gas, which provide the raw material for gas giants which are in the process of forming.

Therefore, the astronomers concluded, gas giants have to form in less than five million years or they probably will not form at all.

"Even though astronomers have detected hundreds of Jupiter-mass planets around other stars, our results suggest that such planets must form extremely fast," said the study's lead scientist Thayne Currie of the Harvard-Smithsonian Center for Astrophysics.

"Whatever process is responsible for forming 'Jupiters' has to be incredibly efficient."

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**_______** · 06-26-2011, 07:37 AM

jupiter is the planet of expansion, so no suprises! usually saturnine people gain a lot of weight as they get older, too...

**Phil75231** · 08-09-2011, 03:51 AM

it's because baby jupiter was the right size, and the right distance from the sun, to trap hydrogen and helium molecules on its surface. (colder molecules move slower, and hence have more difficulty reaching a planet's escape velocity, than warmer molecules do).

Trapping more hydrogen, helium, and other substances increases its mass (and hence its gravity even more), enabling it to trap even more mass - causing a positive feedback loop.