Comments on: Earth. Ground. Inexpensive. Soon. http://oklo.org/2006/08/09/earth-ground-inexpensive-soon/ characterizing planetary systems Wed, 18 Apr 2012 18:53:22 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: systemic - speculations http://oklo.org/2006/08/09/earth-ground-inexpensive-soon/comment-page-1/#comment-350 systemic - speculations Fri, 29 Sep 2006 23:44:18 +0000 http://oklo.org/?p=117#comment-350 [...] 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: systemic - Thresholds http://oklo.org/2006/08/09/earth-ground-inexpensive-soon/comment-page-1/#comment-254 systemic - Thresholds Tue, 15 Aug 2006 21:56:19 +0000 http://oklo.org/?p=117#comment-254 [...] At La Silla, Alpha Centauri never quite sets below the horizon. From roughly October through December, however, the star is generally too low in the sky to be adequately observed. This generates a yearly periodicity in a simulated 5-year radial velocity time series: (Note that in the original version of last week’s post, I posted an incorrect file version of this figure. The plot has now been replaced in the post with the correct plot.) [...] [...] At La Silla, Alpha Centauri never quite sets below the horizon. From roughly October through December, however, the star is generally too low in the sky to be adequately observed. This generates a yearly periodicity in a simulated 5-year radial velocity time series: (Note that in the original version of last week’s post, I posted an incorrect file version of this figure. The plot has now been replaced in the post with the correct plot.) [...]

]]> By: greg http://oklo.org/2006/08/09/earth-ground-inexpensive-soon/comment-page-1/#comment-253 greg Tue, 15 Aug 2006 21:54:15 +0000 http://oklo.org/?p=117#comment-253 I just fixed several small errors in the original version of this post. In the original version of the post, the wrong figure was used for the overall time series. This figure came from an earlier version of the KeckTAC program which did not include the yearly observing cycle. Greg I just fixed several small errors in the original version of this post. In the original version of the post, the wrong figure was used for the overall time series. This figure came from an earlier version of the KeckTAC program which did not include the yearly observing cycle.

Greg

]]> By: greg http://oklo.org/2006/08/09/earth-ground-inexpensive-soon/comment-page-1/#comment-246 greg Thu, 10 Aug 2006 20:06:08 +0000 http://oklo.org/?p=117#comment-246 Hi Darin, Very interesting point. A habitable terrestrial planet orbiting Alpha Centauri B would induce an astrometric wobble of a few micro arc seconds. Our plan is to get the RV telescope built during the next few years, and have the planet discovered before Kepler can return 4 years of photometric data (on other stars) ;) Astrometry seems like a great way to confirm the existence of the Alpha Cen B planets... Greg Hi Darin,

Very interesting point. A habitable terrestrial planet orbiting Alpha Centauri B would induce an astrometric wobble of a few micro arc seconds. Our plan is to get the RV telescope built during the next few years, and have the planet discovered before Kepler can return 4 years of photometric data (on other stars) ;)

Astrometry seems like a great way to confirm the existence of the Alpha Cen B planets…

Greg

]]> By: Centauri Dreams » Blog Archive » Simulated Planets Around Centauri B http://oklo.org/2006/08/09/earth-ground-inexpensive-soon/comment-page-1/#comment-245 Centauri Dreams » Blog Archive » Simulated Planets Around Centauri B Thu, 10 Aug 2006 13:02:47 +0000 http://oklo.org/?p=117#comment-245 [...] Keen on detecting such a planet, Laughlin now advocates a radial-velocity investigation of Centauri B, toward which end he has been working up detailed feasibility studies. The method: model terrestrial planetary systems in stable orbits using accepted accretion models, then work out hypothetical observing strategies. The radial velocity measurements thus produced are fed to the downloadable systemic console for manipulation. [...] [...] Keen on detecting such a planet, Laughlin now advocates a radial-velocity investigation of Centauri B, toward which end he has been working up detailed feasibility studies. The method: model terrestrial planetary systems in stable orbits using accepted accretion models, then work out hypothetical observing strategies. The radial velocity measurements thus produced are fed to the downloadable systemic console for manipulation. [...]

]]> By: darin http://oklo.org/2006/08/09/earth-ground-inexpensive-soon/comment-page-1/#comment-243 darin Wed, 09 Aug 2006 19:04:17 +0000 http://oklo.org/?p=117#comment-243 Greg- How's the astrometric signal from a 1 Earth-mass planet at Alpha Centari? Since the star is so close, the signal should be pretty big. Some (ground-based) interferometers are already getting down to tens of microarcseconds and the binary nature might actually help (it provides a ~stable reference to then watch the tiny barycenter motion of the other star and planet). Ideally, you would still want to combine the astrometric measurements with a lot of spectroscopy, but you wouldn't need ~100000 RV points if you had some great astrometry too. In addition, you get the full three-dimensional orbit, which is an excellent bonus. Darin Greg-

How’s the astrometric signal from a 1 Earth-mass planet at Alpha Centari? Since the star is so close, the signal should be pretty big. Some (ground-based) interferometers are already getting down to tens of microarcseconds and the binary nature might actually help (it provides a ~stable reference to then watch the tiny barycenter motion of the other star and planet). Ideally, you would still want to combine the astrometric measurements with a lot of spectroscopy, but you wouldn’t need ~100000 RV points if you had some great astrometry too. In addition, you get the full three-dimensional orbit, which is an excellent bonus.

Darin

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