Comments on: Sirius http://oklo.org/2008/11/25/sirius/ characterizing planetary systems Wed, 18 Apr 2012 18:53:22 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Lab Lemming http://oklo.org/2008/11/25/sirius/comment-page-1/#comment-10193 Lab Lemming Wed, 26 Nov 2008 03:42:04 +0000 http://oklo.org/?p=301#comment-10193 What is the probability that the brightest close star in any given run will be brighter than Canopus? That might give us a better feel for how unusual it is for bright and close to be correlated. What is the probability that the brightest close star in any given run will be brighter than Canopus? That might give us a better feel for how unusual it is for bright and close to be correlated.

]]> By: greg http://oklo.org/2008/11/25/sirius/comment-page-1/#comment-10192 greg Wed, 26 Nov 2008 01:44:57 +0000 http://oklo.org/?p=301#comment-10192 Cool point. To zeroth order, that's correct. Sirius is almost exactly twice the distance of Alpha Cen. Main sequence A stars like Sirius are, however, somewhat more than 8x rarer than early K main sequence stars like Alpha Cen B. The shortfall in bright Sirius-type stars (to get to ~3% for both) is made up by the scattering of somewhat evolved stars in the local 25pc volume. Also, the 1-sigma error on the 3% "unusualnesses" in the particular simulation that I did is ~(sqrt(30)/30)*0.03, which is ~0.5% for both stars. Were I a perfectionist, I would have stated 3+/-0.5% for both. Cool point. To zeroth order, that’s correct.

Sirius is almost exactly twice the distance of Alpha Cen. Main sequence A stars like Sirius are, however, somewhat more than 8x rarer than early K main sequence stars like Alpha Cen B. The shortfall in bright Sirius-type stars (to get to ~3% for both) is made up by the scattering of somewhat evolved stars in the local 25pc volume. Also, the 1-sigma error on the 3% “unusualnesses” in the particular simulation that I did is ~(sqrt(30)/30)*0.03, which is ~0.5% for both stars. Were I a perfectionist, I would have stated 3+/-0.5% for both.

]]> By: Lab Lemming http://oklo.org/2008/11/25/sirius/comment-page-1/#comment-10191 Lab Lemming Tue, 25 Nov 2008 23:03:52 +0000 http://oklo.org/?p=301#comment-10191 So does the ratio of A stars to K stars equal the cube of the ratio of the distances between those two systems? So does the ratio of A stars to K stars equal the cube of the ratio of the distances between those two systems?

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