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D/1770 L1 and P/2007 T2

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  • Dimitry Chestnov
    Dear colleagues, One more time I found probably identical comets. I am beginner in orbit linking. There was two false alarms about orbit identity on my
    Message 1 of 6 , Oct 1, 2009
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      Dear colleagues,

      One more time I found probably identical comets. I am beginner in orbit linking. There was two "false alarms" about orbit identity on my account, but recently I successfully linked P/2003 A1 with P/2009 R2 while on NEOCP (see IAUC 9072).

      Well, I think that P/2007 T2 (Kowalski) = D/1770 L1 (Lexell). They both have almost the same orbital elements (at the observed epoches) and both orbits are unstable. Tisserand parameters TJ of these comets are very close. I know that some comets, that frequently approach Jupiter, tend to jump between two distinct orbits several times.

      As we know, D/1770 L1 (Lexell) was thrown out from its orbit by Jupiter in 1779 to a distant, even probably a hyperbolic, orbit (too high uncertainty for quantitative estimate). In 2004, P/2007 T2 was injected by Jupiter from a distant orbit to its present orbit, that resembles orbit of D/1770 L1.

      Using EXORB software, I generated 1000 "Monte-Carlo" clones of P/2007 T2 and went back in time in tens of years ago in SOLEX. Some of the clones came from time to time to orbits similar to D/1770 L1.

      I have a question to members of this group, especially to Maik. What do you think about it?

      Best regards,
      Dimitry Chestnov
    • Maik Meyer
      Dimitry, unfortunately I will not be able to look into this matter until Sunday evening. But I think without having a 2-apparition orbit for P/2007 T2, we can
      Message 2 of 6 , Oct 1, 2009
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        Dimitry,

        unfortunately I will not be able to look into this matter until Sunday evening.

        But I think without having a 2-apparition orbit for P/2007 T2, we can not make at
        least some reliable statements. There would be so many perturbations involved that
        one needs at least one firm orbit based on at least 2 apparitions. Even then, it
        might be that it is still uncertain. For instance, the unambiguous identification
        of D/1783 W1 and P/2003 A1 was only possible with your linkage with P/2009 R2.

        I will have a look at it early next week.

        I have also a nice candidate which might never be confirmed. P/2006 T1 (Levy)
        might be identical to C/1743 C1. Unfortunately the 2006 orbit is too uncertain.
        Also here I hope for the next apparition to have more definitive orbits to work
        with.

        Cheers, Maik
        --
        If they give you ruled paper, write the other way. * Juan Ramon Jimenez
        ________________________________________________________________________
        maik@... http://www.comethunter.de
        German Comet Section http://www.fg-kometen.de
        http://groups.yahoo.com/group/comets-ml
      • cspratt2001
        Is EXORB software readily available? If so from where? Thanks. Chris. Spratt Victoria, BC
        Message 3 of 6 , Oct 1, 2009
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          Is EXORB software readily available? If so from where?

          Thanks.

          Chris. Spratt
          Victoria, BC



          --- In comets-ml@yahoogroups.com, "Dimitry Chestnov" <chestd@...> wrote:
          >
          > Dear colleagues,
          >
          > One more time I found probably identical comets. I am beginner in orbit linking. There was two "false alarms" about orbit identity on my account, but recently I successfully linked P/2003 A1 with P/2009 R2 while on NEOCP (see IAUC 9072).
          >
          > Well, I think that P/2007 T2 (Kowalski) = D/1770 L1 (Lexell). They both have almost the same orbital elements (at the observed epoches) and both orbits are unstable. Tisserand parameters TJ of these comets are very close. I know that some comets, that frequently approach Jupiter, tend to jump between two distinct orbits several times.
          >
          > As we know, D/1770 L1 (Lexell) was thrown out from its orbit by Jupiter in 1779 to a distant, even probably a hyperbolic, orbit (too high uncertainty for quantitative estimate). In 2004, P/2007 T2 was injected by Jupiter from a distant orbit to its present orbit, that resembles orbit of D/1770 L1.
          >
          > Using EXORB software, I generated 1000 "Monte-Carlo" clones of P/2007 T2 and went back in time in tens of years ago in SOLEX. Some of the clones came from time to time to orbits similar to D/1770 L1.
          >
          > I have a question to members of this group, especially to Maik. What do you think about it?
          >
          > Best regards,
          > Dimitry Chestnov
          >
        • astroched
          ... http://chemistry.unina.it/~alvitagl/solex/
          Message 4 of 6 , Oct 1, 2009
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            --- In comets-ml@yahoogroups.com, "cspratt2001" <cspratt@...> wrote:
            >
            > Is EXORB software readily available? If so from where?



            http://chemistry.unina.it/~alvitagl/solex/
          • kronk@cometography.com
            K. Kinoshita s web site (http://jcometobs.web.fc2.com/pcmt/k07t2.htm) indicates that P/2007 T2 passed 0.0195 AU from Jupiter on 2004 September 29 and that the
            Message 5 of 6 , Oct 1, 2009
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              K. Kinoshita's web site (http://jcometobs.web.fc2.com/pcmt/k07t2.htm)
              indicates that P/2007 T2 passed 0.0195 AU from Jupiter on 2004 September
              29 and that the orbital period was altered from 9.8 years to 5.4 years.
              Prior to that date, there were no significant close encounters back to
              the 1893 apparition (the earliest date the comet's orbit is integrated
              to), when the period was about 9.2 years.

              These details are important because of the examinations of the orbital
              motion of D/1770 L1 (Lexell) after its last close encounter with Jupiter
              (0.0015-0.0016 AU) in 1779. In 1976, E. I. Kazimirchak-Polonskaya and S.
              D. Shaporev concluded that the comet was probably placed into an orbit
              with a period of 260 years, although a much longer period was not out of
              the question. In 2003, Kinoshita found that the comet was ejected into
              an orbit with a period of about 200 years. Kinoshita also indicated the
              perihelion distance was likely increased to 5.2 AU by the 1779
              encounter. From both of these sets of calculations, it is probably safe
              to say that comet Lexell would not have returned to the sun's vicinity
              before 1984, if not much later.

              Sincerely,
              Gary



              > -------- Original Message --------
              > Subject: Re: [comets-ml] D/1770 L1 and P/2007 T2
              > From: "Maik Meyer" <maik@...>
              > Date: Thu, October 01, 2009 6:35 am
              > To: <comets-ml@yahoogroups.com>
              > Dimitry,
              > unfortunately I will not be able to look into this matter until Sunday evening.
              > But I think without having a 2-apparition orbit for P/2007 T2, we can not make at
              > least some reliable statements. There would be so many perturbations involved that
              > one needs at least one firm orbit based on at least 2 apparitions. Even then, it
              > might be that it is still uncertain. For instance, the unambiguous identification
              > of D/1783 W1 and P/2003 A1 was only possible with your linkage with P/2009 R2.
              > I will have a look at it early next week.
              > I have also a nice candidate which might never be confirmed. P/2006 T1 (Levy)
              > might be identical to C/1743 C1. Unfortunately the 2006 orbit is too uncertain.
              > Also here I hope for the next apparition to have more definitive orbits to work
              > with.
              > Cheers, Maik
              > --
              > If they give you ruled paper, write the other way. * Juan Ramon Jimenez
              > ________________________________________________________________________
              > maik@... http://www.comethunter.de
              > German Comet Section http://www.fg-kometen.de
              > http://groups.yahoo.com/group/comets-ml
            • Maik Meyer
              Dimitry, and all, ... that being said I will just add that the astrometry for P/2007 T2 is comparably bad and the current orbital solution far from being
              Message 6 of 6 , Oct 5, 2009
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                Dimitry, and all,

                Gary wrote:

                > K. Kinoshita's web site (http://jcometobs.web.fc2.com/pcmt/k07t2.htm)
                > indicates that P/2007 T2 passed 0.0195 AU from Jupiter on 2004 September
                > 29 and that the orbital period was altered from 9.8 years to 5.4 years.
                > Prior to that date, there were no significant close encounters back to
                > the 1893 apparition (the earliest date the comet's orbit is integrated
                > to), when the period was about 9.2 years.
                >
                > These details are important because of the examinations of the orbital
                > motion of D/1770 L1 (Lexell) after its last close encounter with Jupiter
                > (0.0015-0.0016 AU) in 1779. In 1976, E. I. Kazimirchak-Polonskaya and S.
                > D. Shaporev concluded that the comet was probably placed into an orbit
                > with a period of 260 years, although a much longer period was not out of
                > the question. In 2003, Kinoshita found that the comet was ejected into
                > an orbit with a period of about 200 years. Kinoshita also indicated the
                > perihelion distance was likely increased to 5.2 AU by the 1779
                > encounter. From both of these sets of calculations, it is probably safe
                > to say that comet Lexell would not have returned to the sun's vicinity
                > before 1984, if not much later.

                that being said I will just add that the astrometry for P/2007 T2 is comparably
                bad and the current orbital solution far from being conclusive, especially when it
                comes to backward integration. A lot of observations have to be excluded to reach
                a reasonable overall residual, and of course the selection of the excluded
                observations strongly affects the final solution.

                Add to that that the orbit for D/1770 L1 is of course also far from being definite
                and a forward integration can only give a rough idea about possible developments
                of the orbit.

                Presently it is simply impossible to judge about your suggestion and you will have
                to wait at least for another apparition to repeat a backwards integration.

                The more close encounters wirth Jupiter are involved the more chaotic and less
                predictable future/past orbits will be, especially with non-gravitational forces
                also present.

                Cheers, Maik
                --
                If they give you ruled paper, write the other way. * Juan Ramon Jimenez
                ________________________________________________________________________
                maik@... http://www.comethunter.de
                International Comet Quarterly http://cfa-www.harvard.edu/icq/icq.html
                http://groups.yahoo.com/group/comets-ml
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