Re: Number of low eccentricity distant planets

Crown-Horned Snorkack wrote:

> On 23 veebr, 23:40, Erik Max Francis <m...@[EMAIL PROTECTED]
> wrote:
>> Mike Williams wrote:
>>> Decide what value you consider to be "low eccentricity" and count off
>>> the pro****tion. As a guide, the eccentricity of the Earth is 0.0167.
>>> About 16% of those extrasolar planets have orbits that are less
>>> eccentric than that of the Earth. I ignored exoplanets for which the
>>> eccentricity has not been calculated.
>> Note that there are very strong selection effects here which are sure
to
>> affect the distribution of known eccentricities.  The real answer is
>> that we don't yet know.
>>
> Precisely how do the selection effects affect the distribution?
> 
> For one thing, selection effect favour close-in hot Jupiters - and
> these tend to have low eccentricities. After excluding the short
> period planets, what is the remaining picture?

We don't know what the true distribution _actually is_, but we know that 
our detection methods favor large bodies, close in.  These are likely to 
have a skewed distribution of eccentricities compared to the true 
distribution, due to tidal effects.

That is the whole point here.  We do not know what the actual 
distribution is, so pretending that what we've found is meaningful is 
highly premature.

-- 
Erik Max Francis && max@[EMAIL PROTECTED]
 && http://www.alcyone.com/max/
  San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M erikmaxfrancis
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