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Re: P/2010 A2 - a comet after all!

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  • hal.weaver
    Dear David, Analysis of the Hubble images of P/2010 A2 strongly favor the interpretation that there was *not* any cometary activity in P/A2 and that a
    Message 1 of 6 , Aug 26, 2010
      Dear David,

      Analysis of the Hubble images of P/2010 A2 strongly favor the interpretation that there was *not* any "cometary" activity in P/A2 and that a collisional process, of short duration in late-Feb or early-Mar 2009, produced the display we all observed.

      This Hubble finding is independently supported by analysis of ground-based and Rosetta/OSIRIS images of P/A2.

      Our Hubble results (Jewitt et al.) will be published in a Nature paper that should be out soon.


      Hal Weaver

      --- In comets-ml@yahoogroups.com, "David Seargent" <seargent@...> wrote:
      > Hi all,
      > It seems that P/2010 A2 might be a comet after all. In their paper "Water-ice driven activity on Main-Belt Comet P/2010 A2 (LINEAR)?", Fernando Moreno et. al. analyse a series of images taken last January from Observatorio del los Muchachos on La Palma in Spain and find that the dust tail of this comet is best explained as consisting of large particles ejected over a period of about 8 months from late March 2009 until early December, with maximum activity in June last year. The ejection velocities fit ordinary cometary activity driven by sublimating ice. The tail cannot be explained by a single burst of particles as would be expected from a collision between two asteroids.
      > A minor impact may have triggered the activity, but the increase and decrease in the quantity of ejected dust over time reflects activity that built up for about two months, then levelled off for a while before decreasing and eventually stopping altogether just after perihelion. Maybe the deposit of exposed ice was exhausted by then, or the active region turned away from direct sunlight. According to Moreno et al, activity was probably confined to a single region at high southerly latitudes on the nucleus surface.
      > These results bring this object more into line with the other Main-Belt comets and once more raise the question as to whether it is a true member of the S-Type Flora family or a C-Type interloper. I ran a D-criterion comparison of the orbit of this object and that of Flora and the "Flora interloper" 298 Baptistina and found that for the latter D = 0.134 while for the former D = 0.272. Clearly, the orbit of A2 has a greater similarity with 298 than with Flora.
      > Regards,
      > David Seargent
      > [Non-text portions of this message have been removed]
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