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Re: [comets-ml] Was there a 2nd outburst of Holmes after all?

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  • Alfredo Pereira
    -- Here is a extract from a longer descriptive note, I sent to the ICQ and Astrosite Groningen (where it is posted) on Jan 25. Perhaps it relates with one of
    Message 1 of 6 , Feb 25, 2008
      --

      Here is a extract from a longer descriptive note, I sent to the ICQ and
      Astrosite Groningen (where it is posted) on Jan 25. Perhaps it relates
      with one of the events mentioned by Kidger.

      "2008 Jan 25.87 UT: (...) a small non-stellar central condensation is
      visible; I took great care to check whether this was a ghost from Beta Per,
      and it is visible at the same location while moving the instrument around
      the field; this feature is similarly visible in 14x100 binoculars and
      naked eye, and there is no background star at the current position; may be
      the fading coma (or the dimmed coma due to Beta Per) is leaving this inner
      area more prominent by contrast; for many weeks the coma has looked very
      uniform, with a flat brightness profile in the 5x22 monocular, so tonight
      it was quite a dramatic change".

      Cheers,

      Alfredo Pereira
      --
    • francois kugel
      I dont know if one can speak about outburst, but after January 25 the magnitude of the nucleus seems to have to increase approximately 1.5 magnitude and the
      Message 2 of 6 , Feb 25, 2008
        I dont know if one can speak about outburst, but after January 25 the
        magnitude of the nucleus seems to have to increase approximately 1.5
        magnitude and the fall of glare thereafter seems to have decreased:

        http://pagesperso-orange.fr/fkometes/images/comets_img/17P-courbe%20mag.m1-A77.jpg

        Francois Kugel
        #A77


        Alfredo Pereira a écrit :
        >
        > --
        >
        > Here is a extract from a longer descriptive note, I sent to the ICQ and
        > Astrosite Groningen (where it is posted) on Jan 25. Perhaps it relates
        > with one of the events mentioned by Kidger.
        >
        > "2008 Jan 25.87 UT: (...) a small non-stellar central condensation is
        > visible; I took great care to check whether this was a ghost from Beta
        > Per,
        > and it is visible at the same location while moving the instrument around
        > the field; this feature is similarly visible in 14x100 binoculars and
        > naked eye, and there is no background star at the current position;
        > may be
        > the fading coma (or the dimmed coma due to Beta Per) is leaving this
        > inner
        > area more prominent by contrast; for many weeks the coma has looked very
        > uniform, with a flat brightness profile in the 5x22 monocular, so tonight
        > it was quite a dramatic change".
        >
        > Cheers,
        >
        > Alfredo Pereira
        > --
        >
        >
      • fvs62
        Dear Ñolleagues, ... semi-regular periodicity of nearly a couple of weeks (or a multiple of this amount). Don t know if these are genuine (i.e. if they
        Message 3 of 6 , Feb 27, 2008
          Dear Ñolleagues,

          --- In comets-ml@yahoogroups.com, "gvnn64\@...\.it" <gvnn64@...>
          wrote:

          > Interesting evidence.
          >
          > If you see the general lightcurve produced by the Spanish team:
          > http://www.astrosurf.com/comets/cometas/17p/image009.gif
          > it seems that there have been other fluctuations, possibly with a
          semi-regular periodicity of nearly a couple of weeks (or a multiple
          of this amount). Don't know if these are genuine (i.e. if they
          reflects actual physical variation of the comet) or are due to some
          other effect (at this level, is very difficult to say for sure in
          either way).
          >
          > Cheers,
          > Giovanni Sostero
          >

          In our paper (Filonenko V. S., Churyumov K. I. New peculiarities of
          cometary outburst activity; http://ads.nao.ac.jp/abs/
          2006AdSpR..38.1940F) we have found a mean period 6.8d +/- 0.6d of the
          outbursts activity for all 27 comets which had been studied in this
          paper.

          Best regards,
          Vitaly Filonenko.
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