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The coming approach of comet 45P/Honda-Mrkos-Padujsakova

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  • iferrinv
    Hello to all: Many of you are aware that comet 45P is going to have a close approach to Earth on August 15th 2011. At that moment the comet will be at
    Message 1 of 6 , Jul 15, 2011
      Hello to all:
      Many of you are aware that comet 45P is going to have
      a close approach to Earth on August 15th 2011. At that
      moment the comet will be at declination -70 degrees,
      Delta= 0.06 AU which implies a scale of 43 km/second of
      arc. It will then move rapidly to the north where it will
      be observable in better conditions.
      The secular light curve of this comet has been
      published in the "Atlas of Secular Light Curves of Comets"
      and it is available at

      http://arxiv.org/ftp/arxiv/papers/0909/0909.3498.pdf

      The diameter of this comet is 0.86+-0.37 km and its
      photometric age, PAGE = 55+-3 comet years. According
      to these numbers, this is a dwarf comet of middle age.

      Two light curves are available, the log plot and the
      time plot. They are useful for planning observations.
      It is interesting to notice that the comet will turn on
      70+-10 days before perihelion. Since perihelion takes
      place on September 29th 2011, 70 days before corresponds
      to July 20+-10 days. It is of great importance to try
      to determine the turn on point of this comet with good
      accuracy. The reason is that this comet is evolving
      very rapidly and this evolution may show up in the turn
      on distance. several revolutions will be need for this
      detection so it is important to determine this number
      accurately now.
      At the turn on time the comet will be at declination
      -22 deg and moving rapidly south toward its encounter with
      Earth, so souther hemisphere observers are favoured.
      I have calculated the amount of water that this
      comet is loosing per revolution, and it is very
      significant. If we convert that to a depth layer, it
      looses 13 m per revolution. Since the radius is
      only 430 m and assuming a constant depth removal, it
      implies that the comet will sublimate away in only
      33 revolutions, a very short time.
      There is a great simmilarity between this comet and
      the recently observed 103P/Hartley 2, and thus I would
      like to predict that if high resolution observations
      of the nucleus were made, it will show a cloud of large
      debris surrounding the nucleus as for 103P.
      Please make an effort to observe this comet at the
      earliest opportunity and for as long as possible. When
      the comet approaches Earth it will be extended in the sky
      and it will be neccessary to use large phtometric appertures
      to include all the coma. I have considered this issue in
      the following paper:

      http://www.webdelprofesor.ula.ve/ciencias/ferrin/teaching/curveofgrowth.pdf

      I am interested in receiving your observations of this
      comet. This is a worthwhile target coming near us soon.
      Kind regards,

      Ignacio Ferrin
      University of Antioquia
      Institute of Physics,
      Medellin, Colombia
      oooooooooooooooooooooooooooooooooooooooooooooooooooooooo
    • Jakub Černý
      Hello Ignacio, Very thanks for an interesting reading! Your work is very good. Unfortunately the conditions of visibility 45P at time near T-70 are very poor
      Message 2 of 6 , Jul 16, 2011
        Hello Ignacio,



        Very thanks for an interesting reading!

        Your work is very good.



        Unfortunately the conditions of visibility 45P at time near T-70 are very
        poor from my latitude.



        Best regards,

        Jakub Cerny



        From: comets-ml@yahoogroups.com [mailto:comets-ml@yahoogroups.com] On Behalf
        Of iferrinv
        Sent: Saturday, July 16, 2011 3:47 AM
        To: comets-ml@yahoogroups.com
        Subject: [comets-ml] The coming approach of comet
        45P/Honda-Mrkos-Padujsakova





        Hello to all:
        Many of you are aware that comet 45P is going to have
        a close approach to Earth on August 15th 2011. At that
        moment the comet will be at declination -70 degrees,
        Delta= 0.06 AU which implies a scale of 43 km/second of
        arc. It will then move rapidly to the north where it will
        be observable in better conditions.
        The secular light curve of this comet has been
        published in the "Atlas of Secular Light Curves of Comets"
        and it is available at

        http://arxiv.org/ftp/arxiv/papers/0909/0909.3498.pdf

        The diameter of this comet is 0.86+-0.37 km and its
        photometric age, PAGE = 55+-3 comet years. According
        to these numbers, this is a dwarf comet of middle age.

        Two light curves are available, the log plot and the
        time plot. They are useful for planning observations.
        It is interesting to notice that the comet will turn on
        70+-10 days before perihelion. Since perihelion takes
        place on September 29th 2011, 70 days before corresponds
        to July 20+-10 days. It is of great importance to try
        to determine the turn on point of this comet with good
        accuracy. The reason is that this comet is evolving
        very rapidly and this evolution may show up in the turn
        on distance. several revolutions will be need for this
        detection so it is important to determine this number
        accurately now.
        At the turn on time the comet will be at declination
        -22 deg and moving rapidly south toward its encounter with
        Earth, so souther hemisphere observers are favoured.
        I have calculated the amount of water that this
        comet is loosing per revolution, and it is very
        significant. If we convert that to a depth layer, it
        looses 13 m per revolution. Since the radius is
        only 430 m and assuming a constant depth removal, it
        implies that the comet will sublimate away in only
        33 revolutions, a very short time.
        There is a great simmilarity between this comet and
        the recently observed 103P/Hartley 2, and thus I would
        like to predict that if high resolution observations
        of the nucleus were made, it will show a cloud of large
        debris surrounding the nucleus as for 103P.
        Please make an effort to observe this comet at the
        earliest opportunity and for as long as possible. When
        the comet approaches Earth it will be extended in the sky
        and it will be neccessary to use large phtometric appertures
        to include all the coma. I have considered this issue in
        the following paper:

        http://www.webdelprofesor.ula.ve/ciencias/ferrin/teaching/curveofgrowth.pdf

        I am interested in receiving your observations of this
        comet. This is a worthwhile target coming near us soon.
        Kind regards,

        Ignacio Ferrin
        University of Antioquia
        Institute of Physics,
        Medellin, Colombia
        oooooooooooooooooooooooooooooooooooooooooooooooooooooooo





        [Non-text portions of this message have been removed]
      • amar sharma
        Dear comet-eers, 1) Wanted to know what would have happened if this was a fresh Oort comet coming in, and not a periodic, at such a close distance of 0.06 AU
        Message 3 of 6 , Jul 22, 2011
          Dear comet-eers,

          1) Wanted to know what would have happened if this was a fresh Oort comet coming in, and not a periodic, at such a close distance of 0.06 AU to Earth in mid-August.

          Cartes du Ciel calculates a long tail (more than 10 degrees) by mid-August. This may not be an active periodic comet, even then it appears to put on a decent show. So what are your calculations for its coma and tail if it were a new comet?

          And is this active more gaseous or dustily?

          2) If you note, as I did from the Cartes du Ciel, this one is super-imposed over LMC, as of 14th August UT 21:00. And on 13th and 14th it passes on either side of 47 Tucana and SMC. Great photo shoot opportunity for imagers below the Equator!

          Even will miss it here. Thanks, Amar, Bangalore, India (+13* N)

          --- On Sat, 16/7/11, iferrinv <ferrin@...> wrote:
          Hello to all:

          Many of you are aware that comet 45P is going to have

          a close approach to Earth on August 15th 2011. At that

          moment the comet will be at declination -70 degrees,

          Delta= 0.06 AU which implies a scale of 43 km/second of

          arc.



          I am interested in receiving your observations of this

          comet. This is a worthwhile target coming near us soon.















          [Non-text portions of this message have been removed]
        • JS & EJ Gifford
          Visually for us in the south of Western Australia it will be a bit frustrating, full Moon coincides with the time it is circumpolar and potentially bright. It
          Message 4 of 6 , Jul 23, 2011
            Visually for us in the south of Western Australia it will be a bit
            frustrating, full Moon coincides with the time it is circumpolar and
            potentially bright. It appears we have only a three or four day window with
            it in dark skies from the 15th August before it moves below our horizon, and
            August is one of our few wet months. Not complaining though, looking forward
            to it.

            Regards, Jim Gifford.



            _____

            From: comets-ml@yahoogroups.com [mailto:comets-ml@yahoogroups.com] On Behalf
            Of amar sharma
            Sent: Saturday, 23 July 2011 2:48 PM
            To: comets-ml@yahoogroups.com
            Subject: Re: [comets-ml] The coming approach of comet
            45P/Honda-Mrkos-Padujsakova





            Dear comet-eers,

            1) Wanted to know what would have happened if this was a fresh Oort comet
            coming in, and not a periodic, at such a close distance of 0.06 AU to Earth
            in mid-August.

            Cartes du Ciel calculates a long tail (more than 10 degrees) by mid-August.
            This may not be an active periodic comet, even then it appears to put on a
            decent show. So what are your calculations for its coma and tail if it were
            a new comet?

            And is this active more gaseous or dustily?

            2) If you note, as I did from the Cartes du Ciel, this one is super-imposed
            over LMC, as of 14th August UT 21:00. And on 13th and 14th it passes on
            either side of 47 Tucana and SMC. Great photo shoot opportunity for imagers
            below the Equator!

            Even will miss it here. Thanks, Amar, Bangalore, India (+13* N)

            --- On Sat, 16/7/11, iferrinv <ferrin@... <mailto:ferrin%40ula.ve> >
            wrote:
            Hello to all:

            Many of you are aware that comet 45P is going to have

            a close approach to Earth on August 15th 2011. At that

            moment the comet will be at declination -70 degrees,

            Delta= 0.06 AU which implies a scale of 43 km/second of

            arc.

            I am interested in receiving your observations of this

            comet. This is a worthwhile target coming near us soon.

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





            [Non-text portions of this message have been removed]
          • terryjlovejoy
            I have been monitoring this comet for the past couple of weeks, and the past few days the almost stellar coma has begin to show an extremely diffuse - but
            Message 5 of 6 , Jul 25, 2011
              I have been monitoring this comet for the past couple of weeks, and the past few days the almost stellar coma has begin to show an extremely diffuse - but large- outer coma. This seem to happen almost on queue on July 20.

              As of July 23, a 20 x 1 minute expsoure by myself suggested a totsl coma diameter of 6' and an integrated magnitude of 13 or perhaps even brighter. One of the problems with determining the total magnitude of such a comet is to careful remove gradients as well as interfering stars contained within the photometric measuring aperture.

              Terry
            • Juan José González Suárez
              I can confirm Terry s suggestion about the coma : 45P/Honda-Mrkos-Pajdusakova: 2011 July 28.04 UT: m1=11.3, Dia.=5 , DC=2/, 20 cm SCT (133x). [ Comet
              Message 6 of 6 , Jul 27, 2011
                I can confirm Terry's suggestion about the coma :

                45P/Honda-Mrkos-Pajdusakova:
                2011 July 28.04 UT: m1=11.3, Dia.=5', DC=2/, 20 cm SCT (133x).
                [ Comet significantly brighter than expected. 5' coma with faint and
                diffuse outer region. Observation made from mountain location under
                very good seeing conditions. Motion checked over a 75-min period.
                Nearby field stars checked in DSS. Limiting star magnitude
                near comet: 15.3 (GSC)].

                ( Alto del Castro - Aralla, alt. 1720 m., Leon, N. Spain ).

                -----------------
                ICQ Format:

                45 2011 07 28.04 S 11.3 TK 20.3T10 133 5 2/ ICQ
                XX GON05
                -----------------

                J. J. Gonzalez

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

                Terry Lovejoy wrote:

                > I have been monitoring this comet for the past couple of weeks, and the past few days the almost stellar coma has begin to show an extremely diffuse - but large- outer coma. This seem to happen almost on queue on July 20.
                >
                > As of July 23, a 20 x 1 minute expsoure by myself suggested a total coma diameter of 6' and an integrated magnitude of 13 or perhaps even brighter. One of the problems with determining the total magnitude of such a comet is to careful remove gradients as well as interfering stars contained within the photometric measuring aperture.
                >
                > Terry
                >
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