Saturday, January 1, 2011

2010 Fourth giant exoplanet strains key theories on planet formation

From New Scientist, we learn that astronomers are puzzled by the four
The discovery of a fourth giant world around the star HR 8799 is straining the two leading theories of how planets form.

Planets are thought to coalesce from a dusty disc around a young star. One model, called core accretion, says that giant planets form when the dust gathers into a rocky core, which then draws in gas to form a massive atmosphere. Another, called disc instability, says that these planets collapse suddenly from sections of the disc.

HR 8799's four planets, each five to 13 times Jupiter's mass, are too far apart to be explained easily by either model, say Christian Marois of the Herzberg Institute of Astrophysics in Victoria, British Columbia, Canada, and colleagues.
Here's a vid:


Graphics time is much too soon for certainty on this one.

See also:

Exoplanets: The planet with 100% life has 0% existence?

Exoplanets: The recent pilgrimage to Darwin's shrine.

Does our solar system occupy a unique position in the universe or just an ordinary one?

Rare? Solar systems like ours are rare?

Astronomer argues that we can test whether Earth is fine-tuned as a science lab

Serious push to find more exoplanets

Exoplanets: Will intelligence be common or rare?