Re: Comet of the century or pipe dream?
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A fragment separating from the nucleus at a typical ~1 m/s at perihelion would have a difference in orbital period of +/-6 years. Being an instrinsically bright comet with a presumably large nucleus likely tens of kilometers in size, fragment separation might be a bit faster, perhaps up to 10x that. In this case, some fragments from the last apparition, if any, could start appearing fairly soon.
Qicheng
On Monday, April 28, 2025 at 02:51:07 p.m. MST, Adrien Coffinet via groups.io <adrien.coffinet2@...> wrote:
After reading a comment on Facebook, I'm wondering how likely it is that there could exist smaller fragments of this comet, that would have been unobservable in the 18th century or before, but that would be observable now or later in the century.
And if so, assuming a typical separation speed, what could we expect as the order of magnitude of delay between the perihelion of such a fragment and that of the main fragment, assuming that it separated N perihelia ago? (At first order, and unless there is a close approach with some planet, I'm assuming that it should be some typical interval corresponding to a separation one perihelion ago, multiplied by N.)
Adrien
Qicheng,
> Very interesting! Do you know what the uncertainty on its angular elements looks like? For multi-apparition objects
> observed only near perihelion, the positional uncertainty is generally dominated by those rather than the timing.
This is the 2097 orbit, "linked" to 1402 with a fixed perihelion date for 1402 which gave the best agreement with the
other apparitions.
Orbital elements:? C/1743 X1
? ? Perihelion 2097 Dec 8.61308 TT;? Constraint: Tp=1402 03 25.16
Epoch 2097 Dec 13.0 TT = JDT 2487320.5? ?Earth MOID: 0.3401? ?Ju: 0.1937
M? ?0.01103081? ? ? ? ? ? ? ? ? ? ? Sa: 0.9243? ? ? ? ? ? ? ? ? ?Meyer
n? ?0.00251447? ? ?Peri.? 151.44926
a? 53.5596075? ? ? Node? ? 49.79851
e? ?0.9957914? ? ? Incl.? ?46.66218? ? ? ? ? ? ? ? ? ? ? ?(J2000 ecliptic)
P 391.97293? ? ? ? ? q 0.22541007? Q 106.893805
110 of 120 observations 1743 Dec. 15-1744 Mar. 4; mean residual 31".95
Here are the sigmas for the angular elements.
sigma_i? ? ? ? ?0.046 deg
sigma_omega? ? ?0.031 deg
sigma_node? ? ? 0.08 deg
> There's a chance it could be already be observable right now if you know exactly where it is. If its nucleus is
> comparable in brightness to that of Hale-Bopp's (H=9), it would be mag ~29 now at r=96 au. If it has the same normalized
> level of dust activity as Hale-Bopp (i.e., 2 mag fainter) and a more typical nucleus albedo (i.e., ~4%), it would be ~3
> mag fainter at mag ~32. Toward the brighter end, it might be a reasonable target for the Roman Space Telescope to
> recover (if that telescope isn't cancelled...).
I wonder what else you'll find if you go down to 30 mag....
:-)
Maik
--
"One cannot discover comets lying in bed." * Lewis Swift
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