More about how Planets Form

[antoniseb]

Here's a New Scientist article about observations of protoplanetarty Disks in the Orion Nebule star forming region. It gives some insight as to the fraction of stars that can form planetary systems.
http://www.newscientistspace.com/article/d...-radiation.html

[folkhemmet]

This is encouraging news, as I remember several years ago some astronomers were saying that protoplanetary discs forming in the harsh environment of OB associations would probably not form, or at least not form gas giants. The newscientist article mentions John Bally of UC. His position on this issue has taken a big turn. Now he believes that the radiation from massive stars in these nascent clusters may actually aid rather than inhibit (which he originally believed) planet formation.

Antoniseb said:
"It gives some insight as to the fraction of stars that can form planetary systems."

I agree. I think it is safe to say that a significant fraction (possibly greater than 50%) of stars have planets.

[Greg]

Another lesson in how things can change once you have more precise observations of the same subject matter. I have always adhered to the principle that most likely our solar system is not an exception but fairly representitive of what is out there around other stars (excluding binary systems.)

[GOURDHEAD]

...that most likely our solar system is not an exception but fairly representitive of what is out there around other stars (excluding binary systems.)

For binary and above systems with separations of more than one AU per solar mass, doesn't the stability of the Earthian, Jovian and Saturnian systems indicate planets with stable orbits of low eccentricity can exist over bilions of years?

[John L]

I've said this many times before: Every time we make new observations we make new discoveries and our ideas about how the universe works might just change. I dislike the absolutist terms used too often in scientific papers on the cutting edge where they claim this observation or that simulation proves this theory and rules out another. This just goes to show that a little better observing or simulating can reverse what had become an accepted idea.

And I'm glad that we can show that stars even forming in the proximity of big hot stars like the Trapezium can still hang onto a possibly planet forming disk. It gives me hope that our inability to find planets around every star we look at is a sign of the limitation of our observing technology rather than the inability of stars to have planets.