Steve Willner ) wrote:
: In article ,
: (Eric Chomko) writes:
: : The high eccentricity of the extraterrestrial gas giants
: : implies that all or nearly all extraterrestrial planets
: : have eccentric orbits and that solar system is uncommon.
:
: Could this be due to us having several gas giants and that Jupiter and
: Saturn are both large? Or that the measurements from AU are much better
: than from LY, and that if we were actually near these extraterrestial
: planets would be much more like our own?

: I don't see why there should be any doubt about the derived
: eccentricities, which are based on the radial velocity curves. The
: problem is selection effects. It's much easier to detect systems
: with heavy planets close to the star than systems like ours, where
: the heavy planets are distant from the star. Observations so far are
: incapable, or at best just barely capable, of detecting solar systems
: like ours.

: Further, does our solar system
: from a few LY appear to have a 20 year wobble that coincides with
: Jupiter and Saturn's synodic period?

: No. With sufficient observations -- which would have to span a few
: decades -- both periods would be seen. Try plotting the sum of two
: sine waves with different amplitudes and periods.

My understanding is that when Jupiter and Saturn are near conjunction,
the barycenter between them and the sun is about 100K miles away from the
solar corona in the direction of the planets. I believe that Asimov
discussed this in his book, "Jupiter".

Also, don't we know about the existence of planets outside the solar
system due to the relationship between the barycenter of the star and its
apparent motion related to it?

Eric

: --
: Steve Willner Phone 617-495-7123
: Cambridge, MA 02138 USA
: (Please email your reply if you want to be sure I see it; include a
: valid Reply-To address to receive an acknowledgement. Commercial
: email may be sent to your ISP.)