Re: ASTRO: Sol-like system discovered

From: Mike Lorrey (mlorrey@yahoo.com)
Date: Sun Jul 13 2003 - 20:39:25 MDT

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    --- Damien Broderick <damienb@unimelb.edu.au> wrote:
    > At 07:55 AM 7/9/03 -0700, Robert wrote:
    >
    > >90 light years from Earth, the Sol-like star HD70642
    > >has a 2x Jupiter mass planet orbiting in a roughly
    > >circular orbit at 3.3 AU from the star with no large
    > >planets detected in orbits closer to the sun.
    >
    > That's the one I mentioned the other day. Wouldn't this mung the Mars
    > equivalent orbit into asteroids, and maybe bugger up the life zone if
    > there's a potentially habitable planet at circa 1 AU? I can see two
    > countervailing side effects: too much hard rain (that crud at 1.5
    > AU), and not enough (if it's mopping the rocks up--but then Mars is
    > plentifully cratered).

    First off, we dont know how large and/or bright the star is. Saying a
    star is 'sol like' is actually a rather broad brush to cover a rather
    significant range of yellow dwarf sizes and brightnesses. How bright it
    is tells us where exactly the life zone is, and therefore whether a
    jovian at 3.3 AU is a good or bad thing.

    Secondly, our moon is at least as important as Jupiter at saving our
    asses from being nothing but a gravel pit. It is the significant
    feature that no amount of astronomy can determine unless we actually GO
    to one of these systems, or build one honking huge interferometer.

    =====
    Mike Lorrey
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