RE: (6995) Minoyama

alessandro odasso Feb 9, 2013

I have found another asteroid in the same DSS plate:

asteroid (4597) Consolmagno

The measures are:
56 03 10.36875 261 12 30 50.55 +05 08 25.5
56 03 10.37431 261 12 30 50.29 +05 08 27.3
56 03 10.40556 261 12 30 48.82 +05 08 37.5

Residuals:
.05+ .03-
.07+ .03-
.05+ .02+

the dT are as follows:
-6.46 sec
-8.70 sec
-4.36 sec

This seems to prove that the timing of the images is correct also for (6995) Minoyama.

Looking at (6995) Minoyama I still wonder whether the 1956 astrometric measurements are correct or affected by some sistematic error: would this explain why the measures, though consistent, show those high residuals?

An indipendent measure taken from some more expert person is really needed.

Best wishes,
Alessandro




> Date: Thu, 7 Feb 2013 07:58:14 -0500
> From: pluto@...
> To: find_orb@yahoogroups.com
> CC: alessandro_odasso@...
> Subject: Re: [find_orb] (6995) Minoyama
>
> Hi Alessandro,
>
> Still a puzzler... here's what I'm getting, using the new version with
> 300 asteroids :
>
> http://www.projectpluto.com/temp/mpec.htm
>
> Specifically, for your three observations, residuals are...
>
> 560310 261 3.35- 1.46+
> 560310 261 3.39- 1.41+
> 560310 261 3.36- 1.47+
>
> All very consistent with one another. The cross-residuals are
> all under .1 arcsecond, with time residuals of about seven minutes.
>
> I'd have to say it's either a timing error of seven minutes for
> all three plates, or an asteroid perturber that isn't among the 300
> considered by Baer and Chesley. (This last possibility would be
> very interesting indeed, if true, but I'd check the timing error
> issue first.)
>
> I assume that if Jim Baer and Steve Chesley were able to find
> 300 objects for which they could find perturbed asteroids with
> measurable effects, then there must be a few more that can be
> determined with more observations. Maybe you've found the 301st.
> Unfortunately, I don't have software readily at hand to solve the
> question, "what asteroids did (6995) approach between 1956 and 2012?"
>
> (Actually, I _can_ answer that for the 300 objects in BC-405,
> using the same trick I used to determine that Pallas had perturbed
> (70401). Turns out that (6995) also came close to (2) Pallas,
> within .01 AU, in early 1968. And one does see a little "twitch" in
> the residuals when asteroids are turned on as perturbers... not much
> of one, though; the flyby was apparently a little too fast, distant,
> and/or in the wrong direction to modify the orbit a lot.)
>
> -- Bill
>
> On 02/07/2013 01:26 AM, alessandro odasso wrote:
> > Bill,
> >
> > many thanks for all faster than light response!
> >
> > You make me wonder whether I am wrong in the astrometry, but here is what I found:
> >
> > 1956 03 10.36875 12 42 59.07 +02 28 39.8
> > 1956 03 10.37431 12 42 58.82 +02 28 41.3
> > 1956 03 10.40556 12 42 57.43 +02 28 50.1
> >
> > --Alessandro


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