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Re: {MPML} Re: 2011 MD: possible junk

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  • Alan Harris
    In addition to astrometry, a spectrum (to see if it looks like titanium paint) and a lightcurve (to see if it features specular flashes) would also be of
    Message 1 of 13 , Jun 23 4:42 PM
      In addition to astrometry, a spectrum (to see if it looks like titanium
      paint) and a lightcurve (to see if it features specular flashes) would also
      be of interest, the latter also to tie down the rotation period for planned
      radar observations.

      All this is particularly interesting in the light of the current brouhaha
      over sending humans to NEAs, of which this one would be a prime target,
      provided it isn't painted white with writing and logos all over it.

      Cheers,

      Alan

      P.S. "nominal" size, assuming albedo ~0.14, would be ~10 m diameter; if
      painted white, could be more like ~5 m -- right in the range for space junk.

      At 12:34 PM 6/23/2011, Bill J Gray wrote:
      > As Peter Birtwhistle first noticed (almost immediately after getting
      >the first follow-up on this object), and as the Sky & Tel article
      >mentions, this is in an earth-like orbit. So there is a good chance
      >it will turn out to be space junk. If so, astrometry ought to show
      >some signs of solar radiation pressure sometime soon.
      >
      > It was last in our neighborhood sometime around 1986 (plus or minus
      >a lot, with no real knowledge of its history before then).
      >
      >-- Bill
      >
      >
      >------------------------------------
      >
      >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      >
      >Posts to this list or information found within may be freely used, with
      >the stipulation that MPML and the originating author are cited as the
      >source of the information.Yahoo! Groups Links
      >
      >
      >
      *******************************************************************
      Alan W. Harris
      Senior Research Scientist
      Space Science Institute
      4603 Orange Knoll Ave. Phone: 818-790-8291
      La Canada, CA 91011-3364 email: awharris@...
      *******************************************************************
    • Brian Skiff
      ... I will at least attempt to get a lightcurve tomorrow night (June 25 UT) if it s actually as bright as advertised and/or the following night. Brian
      Message 2 of 13 , Jun 23 5:18 PM
        On Thu, 2011-06-23 at 16:42 -0700, Alan Harris wrote:
        > In addition to astrometry, a spectrum (to see if it looks like titanium
        > paint) and a lightcurve (to see if it features specular flashes) would also
        > be of interest, the latter also to tie down the rotation period for planned
        > radar observations.


        I will at least attempt to get a lightcurve tomorrow night
        (June 25 UT) if it's actually as bright as advertised
        and/or the following night.


        \Brian
      • Alain
        The question is, how is titanium paint in the visible ? I could try (if not cloudy) to get a spectrum, but visible (up to 700nm), is this sufficient ? You get
        Message 3 of 13 , Jun 23 7:10 PM
          The question is, how is titanium paint in the visible ? I could try (if not
          cloudy) to get a spectrum, but visible (up to 700nm), is this sufficient ?
          You get an albedo versus wavelength curve, is this so specific that you can
          immediately say "this is a space junk" ?
          I have not yet made spectra of rapidly moving targets, and it will be low
          here I believe, but I can try.
          Alain


          -----Original Message-----
          From: mpml@yahoogroups.com [mailto:mpml@yahoogroups.com] On Behalf Of Alan
          Harris
          Sent: jeudi 23 juin 2011 19:42
          To: Bill J Gray; mpml@yahoogroups.com
          Subject: Re: {MPML} Re: 2011 MD: possible junk

          In addition to astrometry, a spectrum (to see if it looks like titanium
          paint) and a lightcurve (to see if it features specular flashes) would also
          be of interest, the latter also to tie down the rotation period for planned
          radar observations.

          All this is particularly interesting in the light of the current brouhaha
          over sending humans to NEAs, of which this one would be a prime target,
          provided it isn't painted white with writing and logos all over it.

          Cheers,

          Alan

          P.S. "nominal" size, assuming albedo ~0.14, would be ~10 m diameter; if
          painted white, could be more like ~5 m -- right in the range for space junk.

          At 12:34 PM 6/23/2011, Bill J Gray wrote:
          > As Peter Birtwhistle first noticed (almost immediately after
          >getting the first follow-up on this object), and as the Sky & Tel
          >article mentions, this is in an earth-like orbit. So there is a good
          >chance it will turn out to be space junk. If so, astrometry ought to
          >show some signs of solar radiation pressure sometime soon.
          >
          > It was last in our neighborhood sometime around 1986 (plus or
          >minus a lot, with no real knowledge of its history before then).
          >
          >-- Bill
          >
          >
          >------------------------------------
          >
          >~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          >
          >Posts to this list or information found within may be freely used, with
          >the stipulation that MPML and the originating author are cited as the
          >source of the information.Yahoo! Groups Links
          >
          >
          >
          *******************************************************************
          Alan W. Harris
          Senior Research Scientist
          Space Science Institute
          4603 Orange Knoll Ave. Phone: 818-790-8291
          La Canada, CA 91011-3364 email: awharris@...
          *******************************************************************



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

          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

          Posts to this list or information found within may be freely used, with the
          stipulation that MPML and the originating author are cited as the source of
          the information.Yahoo! Groups Links




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        • Bill J Gray
          ... The latest DOU extends the arc quite a bit, so much so that I can run an ephemeris back to the start of the Space Age and _almost_ rule out the space junk
          Message 4 of 13 , Jun 24 5:43 AM
            Alan Harris wrote:
            > In addition to astrometry, a spectrum (to see if it looks like titanium
            > paint) and a lightcurve (to see if it features specular flashes) would
            > also be of interest, the latter also to tie down the rotation period for
            > planned radar observations.

            The latest DOU extends the arc quite a bit, so much so that I can
            run an ephemeris back to the start of the Space Age and _almost_ rule
            out the space junk possibility. There's a possible encounter in early
            1962, just maybe. Another night or two should remove (or confirm)
            that possibility.

            There are some timing issues showing up in the data, from enough
            places that I think they may not actually be timing issues, but a
            tumbling or light curve issue instead.

            -- Bill
          • P. Clay Sherrod
            I agree on some interesting timing issues with the astrometry that we obtained last night at ASO; both the photometric spread and some odd placements certainly
            Message 5 of 13 , Jun 24 7:58 AM
              I agree on some interesting timing issues with the astrometry that we obtained last night
              at ASO; both the photometric spread and some odd placements certainly suggest tumbling
              along with the possibility of a highly elongated object.

              Thanks for the updated elements, by the way Bill.

              Clay
              _____
              Dr. P. Clay Sherrod
              Arkansas Sky Observatories
              MPC H45 - Petit Jean Mountain South
              MPC H41 - Petit Jean Mountain
              MPC H43 - Conway West
              http://www.arksky.org/

              ----- Original Message -----
              From: "Bill J Gray" <pluto@...>
              To: "Alan Harris" <awharris@...>
              Cc: <mpml@yahoogroups.com>
              Sent: Friday, June 24, 2011 7:43 AM
              Subject: Re: {MPML} Re: 2011 MD: possible junk


              > Alan Harris wrote:
              >> In addition to astrometry, a spectrum (to see if it looks like titanium
              >> paint) and a lightcurve (to see if it features specular flashes) would
              >> also be of interest, the latter also to tie down the rotation period for
              >> planned radar observations.
              >
              > The latest DOU extends the arc quite a bit, so much so that I can
              > run an ephemeris back to the start of the Space Age and _almost_ rule
              > out the space junk possibility. There's a possible encounter in early
              > 1962, just maybe. Another night or two should remove (or confirm)
              > that possibility.
              >
              > There are some timing issues showing up in the data, from enough
              > places that I think they may not actually be timing issues, but a
              > tumbling or light curve issue instead.
              >
              > -- Bill
              >
              >
              > ------------------------------------
              >
              > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
              >
              > Posts to this list or information found within may be freely used, with the stipulation
              > that MPML and the originating author are cited as the source of the information.Yahoo!
              > Groups Links
              >
              >
              >
              >
            • Adrian Galad
              Except for astrometry, I planned also photometry tonight. However, clouds rolled in too early. From a very short session of several minutes (less than an hour
              Message 6 of 13 , Jun 25 5:15 PM
                Except for astrometry, I planned also photometry tonight. However, clouds rolled
                in too early. From a very short session of several minutes (less than an hour
                including observations during dusk) there is an indication of the fast rotation
                of 2011 MD. Some attenuations repeated wirhin 0.192 h in the lightcurve (an
                overall amplitude of the lightcurve seems to be 0.6 mag). Just maybe...



                Fingers crossed to anyone that could determine it better.

                Adrian






                ________________________________
                From: Brian Skiff <bas@...>
                To: Alan Harris <awharris@...>
                Cc: Bill J Gray <pluto@...>; "mpml@yahoogroups.com"
                <mpml@yahoogroups.com>
                Sent: Fri, June 24, 2011 12:18:23 AM
                Subject: Re: {MPML} Re: 2011 MD: possible junk



                On Thu, 2011-06-23 at 16:42 -0700, Alan Harris wrote:
                > In addition to astrometry, a spectrum (to see if it looks like titanium
                > paint) and a lightcurve (to see if it features specular flashes) would also
                > be of interest, the latter also to tie down the rotation period for planned
                > radar observations.

                I will at least attempt to get a lightcurve tomorrow night
                (June 25 UT) if it's actually as bright as advertised
                and/or the following night.

                \Brian




                [Non-text portions of this message have been removed]
              • whrevr
                Similar situation for us as Adrian reported - got limited data last night due to wind. However, it did indicate sharp attenuations with a periodicity of ~0.19
                Message 7 of 13 , Jun 25 11:53 PM
                  Similar situation for us as Adrian reported - got limited data last night due to wind. However, it did indicate sharp attenuations with a periodicity of ~0.19 hr. Tonight, we got a bit more before wind interfered. Raw data folded with the 0.19 hr period is at

                  http://www.nmt.edu/~bryan/research/work/mro_images/k11m00d

                  One could try twice this. However, minor peaks line up pretty well with
                  just a single large attenuation per cycle??

                  - Bill
                • Alan Harris
                  ... At a solar phase angle of 65 degrees, all bets are off. Based on the narrowness of the deep minimum, and the obvious repetition of the wiggles outside of
                  Message 8 of 13 , Jun 26 10:51 AM
                    At 11:53 PM 6/25/2011, whrevr wrote:
                    >Similar situation for us as Adrian reported - got limited data last night
                    >due to wind. However, it did indicate sharp attenuations with a
                    >periodicity of ~0.19 hr. Tonight, we got a bit more before wind
                    >interfered. Raw data folded with the 0.19 hr period is at
                    >
                    >http://www.nmt.edu/~bryan/research/work/mro_images/k11m00d
                    >
                    >One could try twice this. However, minor peaks line up pretty well with
                    >just a single large attenuation per cycle??
                    >
                    > - Bill

                    At a solar phase angle of 65 degrees, all bets are off. Based on the
                    narrowness of the deep minimum, and the obvious repetition of the wiggles
                    outside of the minimum, I would put my money on the half-period with only
                    one deep minimum per cycle. For such a small body, either period, .19 or
                    .38 h, is plausible. It looks pretty clearly that it is not a tumbler. It
                    will be interesting to see if the shape changes when the phase angle changes.

                    MoreData!

                    Alan

                    *******************************************************************
                    Alan W. Harris
                    Senior Research Scientist
                    Space Science Institute
                    4603 Orange Knoll Ave. Phone: 818-790-8291
                    La Canada, CA 91011-3364 email: awharris@...
                    *******************************************************************
                  • Paolo Bacci
                    Animate Gif http://b09-backman.blogspot.com/ backman -- ... Paolo Bacci B09 backman.altervista.org B33 www.astrofilialtavaldera.it 104 - [Non-text portions of
                    Message 9 of 13 , Jun 27 1:28 AM
                      Animate Gif

                      http://b09-backman.blogspot.com/

                      backman
                      --
                      -----------------------
                      Paolo Bacci
                      B09 backman.altervista.org
                      B33 www.astrofilialtavaldera.it
                      104 -


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