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A new outburst of Comet 17P/Holmes

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  • RICHARD MILES
    Comet 17P/Holmes is a fascinating comet having drawn our attention bigtime when it underwent a superoutburst brightening ~14 magnitudes on 2007 October 24.
    Message 1 of 7 , May 19, 2012
      Comet 17P/Holmes is a fascinating comet having drawn our attention bigtime
      when it underwent a superoutburst brightening ~14 magnitudes on 2007 October
      24. Interestingly, although its activity subsided, it did exhibit a clear
      outburst on 2009 Jan 04. The exact date is known thanks to monitoring by
      Luca Buzzi at Schiaparelli Obs. and by Richard Miles and George Faillace
      using the 2.0-m Faulkes Telescope North. The photometry can be seen here:

      http://www.britastro.org/~rmiles/Images/17P_2008-9_photometry.png

      In 2010 October, the comet reached aphelion at r = 5.188 AU and since then
      it has been approaching the Sun at an ever-increasing rate.

      The latest news is that although the cometary nucleus is still about 4.4 AU
      from the Sun, it has just undergone another distinct outburst, brightening
      by some 1.3 magnitudes as observed using the 2.0-m Faulkes Telescope South.
      Here is the photometry as measured using an aperture radius of 2.4":

      Date R mag
      Apr 13 21.1
      Apr 19 20.9
      May 15 19.7
      May 17 20.1
      May 18 20.2

      The outburst probably occurred on 2012 May 12+/-2 as deduced from images
      taken on each of the above 5 epochs. See:

      http://www.britastro.org/~rmiles/Images/17P_2012May_outburstA.png

      Comet Holmes has some unusual characteristics. It is likely to be a very
      slow rotator: one unofficial estimate is a rotation period of 44+/-2 days.
      Observers located in the southern hemisphere may find this object to be a
      rewarding target for study. Its current apparition comes to an end in about
      August but the next one (2013 March - 2013 September inclusive) will be
      favourable. Perihelion occurs near solar conjunction in 2014 March and it
      then moves northwards occupying a similar region of the sky to its famous
      2007 apparition.

      Given that the 2007 superoutburst was much more energetic than its outburst
      on the occasion of its discovery in 1892, the physical integrity of the
      cometary nucleus may have been compromised in some way so we may have to
      expect the unexpected from this object during the next few years.

      Assistance from the Faulkes Telescope Project led by Dr Paul Roche is
      gratefully acknowledged (see for example:
      http://en.wikipedia.org/wiki/Faulkes_Telescope_Project ) and without which
      none of this work would have been possible.

      Richard Miles
      BAA
    • Dave Herald
      I imaged this comet on Feb 24 and Mar 30. The mean magnitude was 21.0 on both occasions. An image from Feb 24 is at: http://tinyurl.com/7u6t7vk Dave Herald
      Message 2 of 7 , May 19, 2012
        I imaged this comet on Feb 24 and Mar 30. The mean magnitude was 21.0 on both occasions.

        An image from Feb 24 is at:
        http://tinyurl.com/7u6t7vk


        Dave Herald
        Murrumbateman, Australia


        From: RICHARD MILES
        Sent: Sunday, May 20, 2012 7:15 AM
        To: comets-ml@yahoogroups.com ; Comets-disc
        Subject: [comets-ml] A new outburst of Comet 17P/Holmes
        Comet 17P/Holmes is a fascinating comet having drawn our attention bigtime
        when it underwent a superoutburst brightening ~14 magnitudes on 2007 October
        24. Interestingly, although its activity subsided, it did exhibit a clear
        outburst on 2009 Jan 04. The exact date is known thanks to monitoring by
        Luca Buzzi at Schiaparelli Obs. and by Richard Miles and George Faillace
        using the 2.0-m Faulkes Telescope North. The photometry can be seen here:

        http://www.britastro.org/~rmiles/Images/17P_2008-9_photometry.png

        In 2010 October, the comet reached aphelion at r = 5.188 AU and since then
        it has been approaching the Sun at an ever-increasing rate.

        The latest news is that although the cometary nucleus is still about 4.4 AU
        from the Sun, it has just undergone another distinct outburst, brightening
        by some 1.3 magnitudes as observed using the 2.0-m Faulkes Telescope South.
        Here is the photometry as measured using an aperture radius of 2.4":

        Date R mag
        Apr 13 21.1
        Apr 19 20.9
        May 15 19.7
        May 17 20.1
        May 18 20.2

        The outburst probably occurred on 2012 May 12+/-2 as deduced from images
        taken on each of the above 5 epochs. See:

        http://www.britastro.org/~rmiles/Images/17P_2012May_outburstA.png

        Comet Holmes has some unusual characteristics. It is likely to be a very
        slow rotator: one unofficial estimate is a rotation period of 44+/-2 days.
        Observers located in the southern hemisphere may find this object to be a
        rewarding target for study. Its current apparition comes to an end in about
        August but the next one (2013 March - 2013 September inclusive) will be
        favourable. Perihelion occurs near solar conjunction in 2014 March and it
        then moves northwards occupying a similar region of the sky to its famous
        2007 apparition.

        Given that the 2007 superoutburst was much more energetic than its outburst
        on the occasion of its discovery in 1892, the physical integrity of the
        cometary nucleus may have been compromised in some way so we may have to
        expect the unexpected from this object during the next few years.

        Assistance from the Faulkes Telescope Project led by Dr Paul Roche is
        gratefully acknowledged (see for example:
        http://en.wikipedia.org/wiki/Faulkes_Telescope_Project ) and without which
        none of this work would have been possible.

        Richard Miles
        BAA



        ------------------------------------

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        [Non-text portions of this message have been removed]
      • Luca Buzzi
        Dear Richard, thank you for this valuable study, well done. Best regards, Luca Buzzi # 204
        Message 3 of 7 , May 20, 2012
          Dear Richard,
          thank you for this valuable study, well done.

          Best regards,
          Luca Buzzi
          # 204



          Il 19/05/2012 23:15, RICHARD MILES ha scritto:
          > Comet 17P/Holmes is a fascinating comet having drawn our attention bigtime
          > when it underwent a superoutburst brightening ~14 magnitudes on 2007 October
          > 24. Interestingly, although its activity subsided, it did exhibit a clear
          > outburst on 2009 Jan 04. The exact date is known thanks to monitoring by
          > Luca Buzzi at Schiaparelli Obs. and by Richard Miles and George Faillace
          > using the 2.0-m Faulkes Telescope North. The photometry can be seen here:
          >
          > http://www.britastro.org/~rmiles/Images/17P_2008-9_photometry.png
          >
          > In 2010 October, the comet reached aphelion at r = 5.188 AU and since then
          > it has been approaching the Sun at an ever-increasing rate.
          >
          > The latest news is that although the cometary nucleus is still about 4.4 AU
          > from the Sun, it has just undergone another distinct outburst, brightening
          > by some 1.3 magnitudes as observed using the 2.0-m Faulkes Telescope South.
          > Here is the photometry as measured using an aperture radius of 2.4":
          >
          > Date R mag
          > Apr 13 21.1
          > Apr 19 20.9
          > May 15 19.7
          > May 17 20.1
          > May 18 20.2
          >
          > The outburst probably occurred on 2012 May 12+/-2 as deduced from images
          > taken on each of the above 5 epochs. See:
          >
          > http://www.britastro.org/~rmiles/Images/17P_2012May_outburstA.png
          >
          > Comet Holmes has some unusual characteristics. It is likely to be a very
          > slow rotator: one unofficial estimate is a rotation period of 44+/-2 days.
          > Observers located in the southern hemisphere may find this object to be a
          > rewarding target for study. Its current apparition comes to an end in about
          > August but the next one (2013 March - 2013 September inclusive) will be
          > favourable. Perihelion occurs near solar conjunction in 2014 March and it
          > then moves northwards occupying a similar region of the sky to its famous
          > 2007 apparition.
          >
          > Given that the 2007 superoutburst was much more energetic than its outburst
          > on the occasion of its discovery in 1892, the physical integrity of the
          > cometary nucleus may have been compromised in some way so we may have to
          > expect the unexpected from this object during the next few years.
          >
          > Assistance from the Faulkes Telescope Project led by Dr Paul Roche is
          > gratefully acknowledged (see for example:
          > http://en.wikipedia.org/wiki/Faulkes_Telescope_Project ) and without which
          > none of this work would have been possible.
          >
          > Richard Miles
          > BAA
          >
          >
        • RICHARD MILES
          Further to my previous note sent on May 19, George Faillace and I have now observed 17P on several further occasions including earlier today. It now looks that
          Message 4 of 7 , Jul 3, 2012
            Further to my previous note sent on May 19, George Faillace and I have now
            observed 17P on several further occasions including earlier today.

            It now looks that the comet brightened by almost a factor of 4 on 2012 May
            13+/-2 and that since that time it has exhibited no further enhancement in
            activity as can be seen by the latest photometry shown plotted at:

            http://www.britastro.org/~rmiles/Images/17P_2012May_outburstB.png

            Assistance from Alison Tripp of the Faulkes Telescope Project team led by Dr
            Paul Roche is gratefully acknowledged.

            Richard Miles
            BAA
          • gvnn64@libero.it
            Hi Richard, please can you estimate the associated error bars in your photometric measurements? Thanks, Giovanni Sostero
            Message 5 of 7 , Jul 3, 2012
              Hi Richard,
              please can you estimate the associated error bars in your photometric measurements?
              Thanks,
              Giovanni Sostero



              > Further to my previous note sent on May 19, George Faillace and I have now
              > observed 17P on several further occasions including earlier today.
              >
              > It now looks that the comet brightened by almost a factor of 4 on 2012 May
              > 13+/-2 and that since that time it has exhibited no further enhancement in
              > activity as can be seen by the latest photometry shown plotted at:
              >
              > http://www.britastro.org/~rmiles/Images/17P_2012May_outburstB.png
              >
              > Assistance from Alison Tripp of the Faulkes Telescope Project team led by Dr
              > Paul Roche is gratefully acknowledged.
              >
              > Richard Miles
              > BAA
              >
              >
            • RICHARD MILES
              Giovanni, I have calculated the formal errors for the last two observations, so the numbers at present are: Date R mag Apr 13 21.1 Apr 19 20.9 May 13.0
              Message 6 of 7 , Jul 3, 2012
                Giovanni,

                I have calculated the formal errors for the last two observations, so the
                numbers at present are:

                Date R mag
                Apr 13 21.1
                Apr 19 20.9
                May 13.0 +/-2 outburst
                May 15 19.7
                May 17 20.1
                May 18 20.2
                May 22 20.7
                Jun 13 21.0
                Jun 19 21.1
                Jun 20 21.2
                Jun 25 21.10 +/-0.14
                Jul 03 21.24 +/-0.35

                Today's detection was achieved on the basis of a stack of 8 x 120-sec
                SDSS-r' exposures despite the fact that the Moon was 100% illuminated, i.e.
                full moon. The FWHM of stars in the field was 1.4 arcsec.

                Our intention is to publish these results (and earlier ones) when formal
                errors will be derived for all the data.

                Richard


                ----- Original Message -----
                From: <gvnn64@...>
                To: "comets-ml" <comets-ml@yahoogroups.com>
                Sent: Tuesday, July 03, 2012 11:20 AM
                Subject: Re:[comets-ml] 2012 May outburst of Comet 17P/Holmes: update


                > Hi Richard,
                > please can you estimate the associated error bars in your photometric
                > measurements?
                > Thanks,
                > Giovanni Sostero
                >
                >
                >
                >> Further to my previous note sent on May 19, George Faillace and I have
                >> now
                >> observed 17P on several further occasions including earlier today.
                >>
                >> It now looks that the comet brightened by almost a factor of 4 on 2012
                >> May
                >> 13+/-2 and that since that time it has exhibited no further enhancement
                >> in
                >> activity as can be seen by the latest photometry shown plotted at:
                >>
                >> http://www.britastro.org/~rmiles/Images/17P_2012May_outburstB.png
                >>
                >> Assistance from Alison Tripp of the Faulkes Telescope Project team led by
                >> Dr
                >> Paul Roche is gratefully acknowledged.
                >>
                >> Richard Miles
                >> BAA
              • Dave Herald
                For info – I’ve imaged 17P more recently (40cm scope), with the following unfiltered mags: 2012 05 20.36 19.7 2012 05 20.37 21.0 2012 06 07.51 20.4
                Message 7 of 7 , Jul 3, 2012
                  For info – I’ve imaged 17P more recently (40cm scope), with the following unfiltered mags:

                  2012 05 20.36 19.7
                  2012 05 20.37 21.0
                  2012 06 07.51 20.4
                  2012 06 07.52 20.6
                  2012 06 09.41 21.1
                  2012 06 09.42 21.1

                  Measurement aperture was around 3” radius. Given the faintness of the comet, the uncertainty in any individual magnitude measurement is probably about 0.5


                  Dave Herald
                  Murrumbateman, Australia


                  From: gvnn64@...
                  Sent: Tuesday, July 03, 2012 9:20 PM
                  To: comets-ml
                  Subject: Re:[comets-ml] 2012 May outburst of Comet 17P/Holmes: update
                  Hi Richard,
                  please can you estimate the associated error bars in your photometric measurements?
                  Thanks,
                  Giovanni Sostero



                  > Further to my previous note sent on May 19, George Faillace and I have now
                  > observed 17P on several further occasions including earlier today.
                  >
                  > It now looks that the comet brightened by almost a factor of 4 on 2012 May
                  > 13+/-2 and that since that time it has exhibited no further enhancement in
                  > activity as can be seen by the latest photometry shown plotted at:
                  >
                  > http://www.britastro.org/~rmiles/Images/17P_2012May_outburstB.png
                  >
                  > Assistance from Alison Tripp of the Faulkes Telescope Project team led by Dr
                  > Paul Roche is gratefully acknowledged.
                  >
                  > Richard Miles
                  > BAA
                  >
                  >



                  ------------------------------------

                  Comet Observations List: http://groups.yahoo.com/group/CometObs/
                  Comet Images List: http://groups.yahoo.com/group/Comet-Images/

                  NOTICE: Material quoted or re-posted from the Comets Mailing List should be indicated by:

                  Comets Mailing List [date]
                  http://www.yahoogroups.com/group/comets-ml
                  Yahoo! Groups Links




                  [Non-text portions of this message have been removed]
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