http://oklo.org/2006/05/02/gi-no/ characterizing planetary systems Wed, 18 Apr 2012 18:53:22 +0000 hourly 1 http://wordpress.org/?v=3.3.1 http://oklo.org/2006/05/02/gi-no/comment-page-1/#comment-4745 Centauri Dreams » Blog Archive » Red Dwarfs: Dust, Details and Habitability Mon, 31 Mar 2008 14:54:39 +0000 http://oklo.org/?p=73#comment-4745 [...] But note another assumption I’ve made above, one that could stand some scrutiny. I’ve set up one in a thousand as a figure for habitable planet occurrence without any reference to how planets form in the first place. A key question is whether we can assume roughly similar methods of planet formation around M dwarfs as around G stars and the other stellar types. We’re studying models like core accretion and gravitational instability as we develop consistent theories for all this, but our knowledge of what goes on around M dwarfs remains sparse. [...] [...] But note another assumption I’ve made above, one that could stand some scrutiny. I’ve set up one in a thousand as a figure for habitable planet occurrence without any reference to how planets form in the first place. A key question is whether we can assume roughly similar methods of planet formation around M dwarfs as around G stars and the other stellar types. We’re studying models like core accretion and gravitational instability as we develop consistent theories for all this, but our knowledge of what goes on around M dwarfs remains sparse. [...]

]]> http://oklo.org/2006/05/02/gi-no/comment-page-1/#comment-1112 systemic - Lonely Planet Guide to the Hyades Fri, 09 Feb 2007 08:12:11 +0000 http://oklo.org/?p=73#comment-1112 [...] My guess is that Epsilon Tauri b is an example of a planet that formed through the gravitational instability mechanism. Gravitational instability should generally produce more massive planets (e.g. HIP 75458 b, and HD 168443 b and c) and its efficacy will be little-affected by UV radiation from neighboring stars. It likely occurs once per every several hundred stars that are formed, and so it’s perfectly reasonable that there’s one star in the Hyades that has a planet formed via the GI mechanism. For more information, this series: 1, 2, 3, 4, 5, 6, and 7 of oklo posts compares and contrasts the gravitational instability and core accretion theories for giant planet formation. [...] [...] My guess is that Epsilon Tauri b is an example of a planet that formed through the gravitational instability mechanism. Gravitational instability should generally produce more massive planets (e.g. HIP 75458 b, and HD 168443 b and c) and its efficacy will be little-affected by UV radiation from neighboring stars. It likely occurs once per every several hundred stars that are formed, and so it’s perfectly reasonable that there’s one star in the Hyades that has a planet formed via the GI mechanism. For more information, this series: 1, 2, 3, 4, 5, 6, and 7 of oklo posts compares and contrasts the gravitational instability and core accretion theories for giant planet formation. [...]

]]> http://oklo.org/2006/05/02/gi-no/comment-page-1/#comment-106 Centauri Dreams » Blog Archive » Two Ways to Build a Gas Giant Thu, 04 May 2006 13:23:19 +0000 http://oklo.org/?p=73#comment-106 [...] Greg Laughlin (UC-Santa Cruz) sees serious problems with Boss’ model, though he agrees that the process can be involved in some giant planet formation, and he pays particular attention to the Gl 876 system we talked about yesterday. “Another important point to stress is that Alan’s simulations certainly aren’t in error in the sense of being computationally wrong,” says Laughlin. “It’s just that I don’t agree with the generic validity of the initial conditions.” Read all of Laughlin’s comments on gravitational instability here. [...] [...] Greg Laughlin (UC-Santa Cruz) sees serious problems with Boss’ model, though he agrees that the process can be involved in some giant planet formation, and he pays particular attention to the Gl 876 system we talked about yesterday. “Another important point to stress is that Alan’s simulations certainly aren’t in error in the sense of being computationally wrong,” says Laughlin. “It’s just that I don’t agree with the generic validity of the initial conditions.” Read all of Laughlin’s comments on gravitational instability here. [...]

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