Comments on: 208 nights, please http://oklo.org/2006/07/05/208-nights-please/ characterizing planetary systems Fri, 18 Nov 2011 22:27:52 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: systemic - speculations http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-349 systemic - speculations Fri, 29 Sep 2006 23:40:07 +0000 http://oklo.org/?p=107#comment-349 [...] Finally, it’s always good to look at costs. According to the Wikipedia, the total cost of building, launching, servicing, and running HST has been of order 6 billion dollars. It started working as planned in 1994, and will thus have ~15 years of fully functional use. The seven days of ACS time were therefore worth 7.6 million dollars. This is comfortably more than the cost of building a special-purpose telescope to probe the terrestrial planets that are almost certainly orbiting Alpha Centauri B. (For more information, see these oklo.org posts: 1, 2, 3, 4, 5.) [...] [...] Finally, it’s always good to look at costs. According to the Wikipedia, the total cost of building, launching, servicing, and running HST has been of order 6 billion dollars. It started working as planned in 1994, and will thus have ~15 years of fully functional use. The seven days of ACS time were therefore worth 7.6 million dollars. This is comfortably more than the cost of building a special-purpose telescope to probe the terrestrial planets that are almost certainly orbiting Alpha Centauri B. (For more information, see these oklo.org posts: 1, 2, 3, 4, 5.) [...]

]]> By: John-1949 http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-316 John-1949 Tue, 12 Sep 2006 17:18:28 +0000 http://oklo.org/?p=107#comment-316 Planet formation around double stars. Wouldn't the proximity of B [with high orbital eccentricity and a periastron of 11 AU] have a detrimental impact of the formation of planets [in particular terrestrial] in A's HZ and vice versa with A impact on B's planet formation the HZ ? Also if Jupiter (& Saturn & other tag team members) have acted as "policemen"/ "sweepers" of the evoluation of the solar system [which has assisted the evolution of life on Earth], wouldn't the proximity of A and B preclude the formation in each other's planetary systems of the gas giants at 5 to 10 AU and hence eliminate the chances of a alpha Centauri "policeman" to "clean-up" the planetary system ? Planet formation around double stars. Wouldn’t the proximity of B [with high orbital eccentricity and a periastron of 11 AU] have a detrimental impact of the formation of planets [in particular terrestrial] in A’s HZ and vice versa with A impact on B’s planet formation the HZ ? Also if Jupiter (& Saturn & other tag team members) have acted as “policemen”/ “sweepers” of the evoluation of the solar system [which has assisted the evolution of life on Earth], wouldn’t the proximity of A and B preclude the formation in each other’s planetary systems of the gas giants at 5 to 10 AU and hence eliminate the chances of a alpha Centauri “policeman” to “clean-up” the planetary system ?

]]> By: Centauri Dreams » Blog Archive » Water Worlds in Known Exosystems http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-307 Centauri Dreams » Blog Archive » Water Worlds in Known Exosystems Thu, 07 Sep 2006 18:41:23 +0000 http://oklo.org/?p=107#comment-307 [...] But read the whole study, one of the most heartening to come across my desk since Greg Laughlin and Jeremy Wertheimer’s work on Proxima Centauri. It’s Raymond et al., “Exotic Earths: Forming Habitable Worlds with Giant Planet Migration,” in the September 8 issue of Science. One can only imagine Webster Cash’s interest in this paper. The Boulder-based Cash’s New Worlds Imager design, now being considered by NASA, is just what we need in space to actually get an image of some of these water worlds. [...] [...] But read the whole study, one of the most heartening to come across my desk since Greg Laughlin and Jeremy Wertheimer’s work on Proxima Centauri. It’s Raymond et al., “Exotic Earths: Forming Habitable Worlds with Giant Planet Migration,” in the September 8 issue of Science. One can only imagine Webster Cash’s interest in this paper. The Boulder-based Cash’s New Worlds Imager design, now being considered by NASA, is just what we need in space to actually get an image of some of these water worlds. [...]

]]> By: Centauri Dreams » Blog Archive » Simulated Planets Around Centauri B http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-244 Centauri Dreams » Blog Archive » Simulated Planets Around Centauri B Thu, 10 Aug 2006 13:02:29 +0000 http://oklo.org/?p=107#comment-244 [...] Add to that two other factors: At UC-Santa Cruz, Greg Laughlin and Jeremy Wertheimer have shown that Proxima Centauri could perturb the debris disk surrounding the Centauri stars enough to deliver volatiles to inner worlds there. Laughlin has been arguing the Centauri case for some time now, discussing not just the Proxima factor but pointing as well to the metallicity of Alpha Centauri, which is high enough to provide the kind of materials needed to form planets analogous to Earth. [...] [...] Add to that two other factors: At UC-Santa Cruz, Greg Laughlin and Jeremy Wertheimer have shown that Proxima Centauri could perturb the debris disk surrounding the Centauri stars enough to deliver volatiles to inner worlds there. Laughlin has been arguing the Centauri case for some time now, discussing not just the Proxima factor but pointing as well to the metallicity of Alpha Centauri, which is high enough to provide the kind of materials needed to form planets analogous to Earth. [...]

]]> By: systemic - Earth. Ground. Inexpensive. Soon. http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-242 systemic - Earth. Ground. Inexpensive. Soon. Wed, 09 Aug 2006 07:09:28 +0000 http://oklo.org/?p=107#comment-242 [...] In a string of posts last month [most recent here], we laid out the case for the existence of terrestrial planets in the Alpha Centauri system. We argued that if one of these planets has an Earth-mass and a habitable orbit, then it is detectable with a flat-out effort by the HARPS spectrograph. We based our argument on the fact that HARPS was recently used to produce an amazing detection of three Neptune-mass worlds orbiting HD 69830 — an old, chromospherically quiet K0V star that is a near-exact twin of Alpha Centauri B. [...] [...] In a string of posts last month [most recent here], we laid out the case for the existence of terrestrial planets in the Alpha Centauri system. We argued that if one of these planets has an Earth-mass and a habitable orbit, then it is detectable with a flat-out effort by the HARPS spectrograph. We based our argument on the fact that HARPS was recently used to produce an amazing detection of three Neptune-mass worlds orbiting HD 69830 — an old, chromospherically quiet K0V star that is a near-exact twin of Alpha Centauri B. [...]

]]> By: greg http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-198 greg Wed, 05 Jul 2006 17:55:26 +0000 http://oklo.org/?p=107#comment-198 Hi Andy, A paper by Pourbaix et al. (2002) derives an improved orbit for the Alpha Cen AB pair, using RVs from the Anglo Australian Telescope and Coralie. Their data-set rules out circumprimary and circumsecondary planets more massive than about 2 Jupiter masses. With data that's been taken since then, I'm sure that these limits can be brought down quite dramatically, probably to the Saturn-mass regime, and perhaps lower, depending on how frequently the system is being observed. Greg Hi Andy,

A paper by Pourbaix et al. (2002) derives an improved orbit for the Alpha Cen AB pair, using RVs from the Anglo Australian Telescope and Coralie. Their data-set rules out circumprimary and circumsecondary planets more massive than about 2 Jupiter masses. With data that’s been taken since then, I’m sure that these limits can be brought down quite dramatically, probably to the Saturn-mass regime, and perhaps lower, depending on how frequently the system is being observed.

Greg

]]> By: greg http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-197 greg Wed, 05 Jul 2006 17:52:16 +0000 http://oklo.org/?p=107#comment-197 Hi Tom, Thanks for your comment. Aaron has been traveling in Israel this month, and has been out of e-mail contact. We'd be very happy to put your data up on the console. Tau Boo, in fact, is one of the few planet-bearing stars for which RVs are currently unavailable in the published literature. 600 points is an impressive aggregate! If you send the data as a three-column ASCII file with time, rv, and sigma, then we can get it up on the console right away. Send it to laugh at ucolick dot org, with a cc to rivera at ucolick dot org. (If you just have time and rvs, we can just estimate sigma from the internal scatter). Greg Hi Tom,

Thanks for your comment. Aaron has been traveling in Israel this month, and has been out of e-mail contact.

We’d be very happy to put your data up on the console. Tau Boo, in fact, is one of the few planet-bearing stars for which RVs are currently unavailable in the published literature.

600 points is an impressive aggregate!

If you send the data as a three-column ASCII file with time, rv, and sigma, then we can get it up on the console right away. Send it to laugh at ucolick dot org, with a cc to rivera at ucolick dot org. (If you just have time and rvs, we can just estimate sigma from the internal scatter).

Greg

]]> By: TomKaye http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-196 TomKaye Wed, 05 Jul 2006 17:25:14 +0000 http://oklo.org/?p=107#comment-196 Hello Greg, I met Aaron at the SAS meeting and I told him I have 600+ RV measurements of tau Boo. He was going to transfer the data to the console so we could playe with it but I never heard back from him. Is there a way I can translate the data myself? Thanks and congrats on a great website! Tom Kaye Hello Greg,

I met Aaron at the SAS meeting and I told him I have 600+ RV measurements of tau Boo. He was going to transfer the data to the console so we could playe with it but I never heard back from him. Is there a way I can translate the data myself?

Thanks and congrats on a great website!

Tom Kaye

]]> By: andy http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-194 andy Wed, 05 Jul 2006 14:45:15 +0000 http://oklo.org/?p=107#comment-194 Have Alpha Centauri A and B been surveyed for close-in gas giants? Have Alpha Centauri A and B been surveyed for close-in gas giants?

]]> By: Centauri Dreams » Blog Archive » Proxima Centauri and Habitability http://oklo.org/2006/07/05/208-nights-please/comment-page-1/#comment-192 Centauri Dreams » Blog Archive » Proxima Centauri and Habitability Wed, 05 Jul 2006 13:37:33 +0000 http://oklo.org/?p=107#comment-192 [...] The paper is Laughlin and Wertheimer, “Are Proxima and Alpha Centauri Gravitationally Bound,” as yet unpublished. Be sure to read Laughlin’s report on this work on the systemic site (and while you’re there, be sure to check his sly resolution of the Fermi Paradox). He and Wertheimer calculate that Proxima should orbit the Alpha Centauri stars about once every million years, with the semi-major axis of the orbit being roughly 1/6th of a light year. If Proxima is indeed stirring the Centauri planetesimal soup, disloding comets and delivering interesting materials to the inner systems, then the odds on habitability go up. And on that score, it’s humbling and energizing to consider that Proxima, and probably the entire Centauri system, was 2 billion years old when the Sun formed. [...] [...] The paper is Laughlin and Wertheimer, “Are Proxima and Alpha Centauri Gravitationally Bound,” as yet unpublished. Be sure to read Laughlin’s report on this work on the systemic site (and while you’re there, be sure to check his sly resolution of the Fermi Paradox). He and Wertheimer calculate that Proxima should orbit the Alpha Centauri stars about once every million years, with the semi-major axis of the orbit being roughly 1/6th of a light year. If Proxima is indeed stirring the Centauri planetesimal soup, disloding comets and delivering interesting materials to the inner systems, then the odds on habitability go up. And on that score, it’s humbling and energizing to consider that Proxima, and probably the entire Centauri system, was 2 billion years old when the Sun formed. [...]

]]>