Comments on: planet per week http://oklo.org/2007/11/30/planet-per-week/ characterizing planetary systems Wed, 18 Apr 2012 18:53:22 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: systemic - Superearths http://oklo.org/2007/11/30/planet-per-week/comment-page-1/#comment-4998 systemic - Superearths Mon, 16 Jun 2008 19:24:28 +0000 http://oklo.org/?p=260#comment-4998 [...] He predicts 1 to 1.5 Earth sensitivity by around 2010 (extrapolating a trend). [...] [...] He predicts 1 to 1.5 Earth sensitivity by around 2010 (extrapolating a trend). [...]

]]> By: greg http://oklo.org/2007/11/30/planet-per-week/comment-page-1/#comment-4315 greg Mon, 21 Jan 2008 08:13:07 +0000 http://oklo.org/?p=260#comment-4315 Hi Michel, That's an interesting point. I think what you're describing is pretty close to a Bayesian analysis. I know that Eric Ford has been working on this approach for fits to individual systems, but I don't know whether it's been applied to a distribution of systems as you are suggesting... Hi Michel,
That’s an interesting point. I think what you’re describing is pretty close to a Bayesian analysis. I know that Eric Ford has been working on this approach for fits to individual systems, but I don’t know whether it’s been applied to a distribution of systems as you are suggesting…

]]> By: Michel Rouzic http://oklo.org/2007/11/30/planet-per-week/comment-page-1/#comment-4314 Michel Rouzic Mon, 21 Jan 2008 07:25:42 +0000 http://oklo.org/?p=260#comment-4314 The last diagram gave me an idea that I find great. If we assumed a distribution for planets depending on their relevant characteristics (mainly semi-major axis and mass), knowing how sensitive our methods of detection are, we could deduce the distribution of detected planets we'd have, and then we can use that to weight the distribution of planets we know of to deduce a closer estimate to what the true distribution of planets must actually be. If I'm not making myself sufficiently clear, let's take an example. Let's pretend that in the universe there are as many Jupiter-like planets between 1 AU and 2 AU as there are between 4 AU and 8 AU, but that if it was the case, using our detection methods, we would found 5 times as many planets between 1 AU and 2 AU as between 4 AU and 8 AU. Now if we look at the Jupiter-like planets we actually know of and find that we know 7 times as many of them between 1-2 AU as between 4-8 AU, we could deduce that in reality there are 1.4 times as many between 1-2 AU as between 4-8 AU. Furthermore we could apply that to mass, semi-major axis and star mass, this way we could not only properly weigh the distribution in the area covered by the planets we already know of, but we could define more clearly which areas we ignore everything of. Or has it already been somehow done? The last diagram gave me an idea that I find great. If we assumed a distribution for planets depending on their relevant characteristics (mainly semi-major axis and mass), knowing how sensitive our methods of detection are, we could deduce the distribution of detected planets we’d have, and then we can use that to weight the distribution of planets we know of to deduce a closer estimate to what the true distribution of planets must actually be.

If I’m not making myself sufficiently clear, let’s take an example. Let’s pretend that in the universe there are as many Jupiter-like planets between 1 AU and 2 AU as there are between 4 AU and 8 AU, but that if it was the case, using our detection methods, we would found 5 times as many planets between 1 AU and 2 AU as between 4 AU and 8 AU. Now if we look at the Jupiter-like planets we actually know of and find that we know 7 times as many of them between 1-2 AU as between 4-8 AU, we could deduce that in reality there are 1.4 times as many between 1-2 AU as between 4-8 AU.

Furthermore we could apply that to mass, semi-major axis and star mass, this way we could not only properly weigh the distribution in the area covered by the planets we already know of, but we could define more clearly which areas we ignore everything of.

Or has it already been somehow done?

]]> By: andy http://oklo.org/2007/11/30/planet-per-week/comment-page-1/#comment-4110 andy Sun, 16 Dec 2007 00:22:53 +0000 http://oklo.org/?p=260#comment-4110 Point 1 strikes me as a pretty poor reason not to study a planet, especially given the amount of study that non-"earth-like" gas giants get, and given that there are going to be many terrestrials and super-Earths which are NOT Earth-analogues, but point 2 is quite valid. Nevertheless it is quite interesting that it apparently took Gliese 876d to kick off the theoretical study of "super-Earths" started, despite it receiving rather too much heat to be an Earth-analogue, when two super-Earths had been known for such a long time. Interesting also that the pulsar planets do not generally get mentioned as "super-Earths". Point 1 strikes me as a pretty poor reason not to study a planet, especially given the amount of study that non-”earth-like” gas giants get, and given that there are going to be many terrestrials and super-Earths which are NOT Earth-analogues, but point 2 is quite valid.

Nevertheless it is quite interesting that it apparently took Gliese 876d to kick off the theoretical study of “super-Earths” started, despite it receiving rather too much heat to be an Earth-analogue, when two super-Earths had been known for such a long time. Interesting also that the pulsar planets do not generally get mentioned as “super-Earths”.

]]> By: mckinstry http://oklo.org/2007/11/30/planet-per-week/comment-page-1/#comment-4063 mckinstry Thu, 13 Dec 2007 09:35:10 +0000 http://oklo.org/?p=260#comment-4063 andy, the trouble with pulsar planets is twofold: (1) they are not sufficiently 'earth-like': high radiation means no life (as we know it): They are not Earth analogues., and (2)a deficit of data, beyond the periodic effects on the pulsar: eg. spectra from the planet, composition, etc. are hard to detect. Maybe later, if we get other techniques, but until the, all we can do is measure the mass and speculate. andy,

the trouble with pulsar planets is twofold: (1) they are not sufficiently ‘earth-like’: high radiation means no life (as we know it): They are not Earth analogues., and (2)a deficit of data, beyond the
periodic effects on the pulsar: eg. spectra from the planet, composition, etc. are hard to detect. Maybe later, if we get other techniques, but until the, all we can do is measure the mass and speculate.

]]> By: andy http://oklo.org/2007/11/30/planet-per-week/comment-page-1/#comment-4054 andy Wed, 12 Dec 2007 15:05:17 +0000 http://oklo.org/?p=260#comment-4054 If you put the pulsar planets on that graph (why do the pulsar planets seem to get routinely ignored?), we've already got known Earth-mass exoplanets, since 1992, plus a moon-mass world. If you put the pulsar planets on that graph (why do the pulsar planets seem to get routinely ignored?), we’ve already got known Earth-mass exoplanets, since 1992, plus a moon-mass world.

]]> By: luis http://oklo.org/2007/11/30/planet-per-week/comment-page-1/#comment-3918 luis Tue, 04 Dec 2007 22:47:35 +0000 http://oklo.org/?p=260#comment-3918 Hi Greg, talking about interesting developments on extrasolar planets, there is a growing interest in polarimetric observations of exoplanet host stars. In particular, I just came accross this paper that tentatively detects transits of a supposed hydrogen tail to 51 Peg b. http://exoplanet.eu/papers/Ksanfomality_Polarimetry_Stars_Exoplanets_2007.pdf The paper mentions that, if the effect is real, the transit of the tail could be detected in the ultraviolet. I know your time is short but I would love to ear your thoughts on this technique and the possibility of using Hubble or Galex for example, to perform these observations. Cheers, Luis Hi Greg,

talking about interesting developments on extrasolar planets, there is a growing interest in polarimetric observations of exoplanet host stars.

In particular, I just came accross this paper that tentatively detects transits of a supposed hydrogen tail to 51 Peg b.

http://exoplanet.eu/papers/Ksanfomality_Polarimetry_Stars_Exoplanets_2007.pdf

The paper mentions that, if the effect is real, the transit of the tail could be detected in the ultraviolet.

I know your time is short but I would love to ear your thoughts on this technique and the possibility of using Hubble or Galex for example, to perform these observations.

Cheers,

Luis

]]> By: andy http://oklo.org/2007/11/30/planet-per-week/comment-page-1/#comment-3908 andy Sat, 01 Dec 2007 00:20:59 +0000 http://oklo.org/?p=260#comment-3908 Talking of true Jupiter analogues, the <a href="http://exoplanets.org/planets.shtml" rel="nofollow">Catalog of Nearby Exoplanets</a> has some rather interesting parameters for HD 154345b... Steinn Sigurðsson <a href="http://scienceblogs.com/catdynamics/2007/06/an_exo_jupiter_unveiled.php" rel="nofollow">mentioned this one</a> earlier this year, but as yet there has been no official announcement. Talking of true Jupiter analogues, the Catalog of Nearby Exoplanets has some rather interesting parameters for HD 154345b… Steinn Sigurðsson mentioned this one earlier this year, but as yet there has been no official announcement.

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