Re: C/2024 G3 ATLAS orbital plane crossing
Great image! Unforgettable Comet!? Regard
Il mer 30 apr 2025, 12:42 Michael Mattiazzo via <mmatti= [email protected]> ha scritto: Hi all ? FYI. Earth is now crossing the orbital plane of Ghost comet C/2024 G3 ATLAS. This Image was taken on 2025 April 30 at 09:15UT using a remote telescope ITEL-T70 Chile 135 mm f/3.5 Samyang Lens + CMOS. 10x60sec. FOV 7 deg. North right. The dust trail in this image, viewed edge-on, is at least 4 degrees long in PA13. Star above centre is Psi Phe. Delta Phe is below left. Total magnitude of the comet is difficult to ascertain, (approx mag 10) but visual attempts are encouraged. Best situated for southern observers in the morning sky. Despite its disintegration in January, it keeps on giving. ? ? Cheers, Michael ?
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Re: C/2024 G3 ATLAS orbital plane crossing
Wow, very nice images Michael and Rob of the 3+ month disintegrated comet.?
Cheers, Erik
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Re: C/2024 G3 ATLAS orbital plane crossing
Nice work Michael! here's my shot from tonight, with 6.4 degrees of tail visible. What a change from a few weeks ago.
?
Cheers -
?
Rob Kaufman
?
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C/2024 G3 ATLAS orbital plane crossing
Hi all ? FYI. Earth is now crossing the orbital plane of Ghost comet C/2024 G3 ATLAS. This Image was taken on 2025 April 30 at 09:15UT using a remote telescope ITEL-T70 Chile 135 mm f/3.5 Samyang Lens + CMOS. 10x60sec. FOV 7 deg. North right. The dust trail in this image, viewed edge-on, is at least 4 degrees long in PA13. Star above centre is Psi Phe. Delta Phe is below left. Total magnitude of the comet is difficult to ascertain, (approx mag 10) but visual attempts are encouraged. Best situated for southern observers in the morning sky. Despite its disintegration in January, it keeps on giving. ? ? Cheers, Michael ?
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Comet C/2025 F2 (SWAN) > 2025.04.29 from BBO
Hello,
a recent photo of the remnants of comet C/2025 F2 (SWAN) taken by BBO
on 2025.04.29
Best,
BBO
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Re: Possible detection of C/2025 F2 on April 28.86
Nick, ??????? thanks for the photo. I now realise that I also caught the patchy remnants of the comet about 20-30 minutes after your picture. Photo was taken April 29.91 with a Seestar 50 for 4 minutes and then cropped. There are some power lines towards the top of the photo.
Kind regards
Stephen McCann Southampton, UK (N 50¡ã 56.50', W 001¡ã 27.90')
On Wed, 30 Apr 2025 at 07:33, Andrea Aletti via <aletti.andrea= [email protected]> wrote: Dear all, from Schiaparelli Observatory the ex comet C2025 F2 near the NW Horizon two days ago in excellent sky condition Best Regards Andrea Aletti e Federico Bellini MPC204 Il giorno mar 29 apr 2025 alle ore 23:46 Nick James via <comets= [email protected]> ha scritto: Thomas,
Thanks. That's a great image. I've be plagued by distant cirrus near the
horizon to my northwest (probably aircraft contrails) so my transparency
has not been very good. I did have slightly better conditions tonight
(April 29.86) and the comet is more obvious in this stack:
Nick.
On 29/04/2025 11:28, Thomas Lehmann via wrote:
> Two nights earlier I have had a chance to observe whats left of the comet from
> Weimar, Germany. The comet was at an altitude of only 5.5¡ã above horizon but I
> gave it a try with my RASA 11" and ASI6200MC as conditions were exceptionally
> good for my location.
> The brightness near the head (green color channel) as measured within an
> aperture of 3' is
>? ? 2025 04 26.84 UT, m=9.8mag
> and the tail extent is about 20' at P.A.=333¡ã
>
> I am attaching the stacked image (12 minutes total exposure time) and an
> inverted star trail subtracted and stronger smoothed image to highlight the
> dust tail.
>
> Out of curiosity I am attaching a plot of differential extinction measured from
> stars near the comet as it is taken into account by my AIRTOOLS software
> automatically.
>
> CS
> Thomas
>
>
>> Am Tue, 29 Apr 2025 07:42:48 +0100
>> schrieb "Nick James"<comets@...>:
>>
>> Possible detection of C/2025 F2 (SWAN) on April 28.86:
>>
>>
>>
>> A very noisy image taken in very bright twilight but there is a faint
>> patch of material at the right location.
>>
>> Nick James. BAA
>>
>>
>>
>>
>>
>>
|
Re: Possible detection of C/2025 F2 on April 28.86
Nick, Andrea,
thanks for your update on successful observations, great achievment! It is quite
a challenge to image this fuzzy dust cloud and all depends on athmospherical
conditions. Despite fairly good weather the last few days, there has been the
usual haze and cirrus around at my site, so I could not image the comet again.
Thomas
toggle quoted message
Show quoted text
Am Wed, 30 Apr 2025 08:33:02 +0200
schrieb "Andrea Aletti via groups.io" <aletti.andrea@...>:
Dear all, from Schiaparelli Observatory the ex comet C2025 F2 near the NW
Horizon two days ago in excellent sky condition
Best Regards
Andrea Aletti e Federico Bellini MPC204
Il giorno mar 29 apr 2025 alle ore 23:46 Nick James via groups.io <comets=
[email protected]> ha scritto:
Thomas,
Thanks. That's a great image. I've be plagued by distant cirrus near the
horizon to my northwest (probably aircraft contrails) so my transparency
has not been very good. I did have slightly better conditions tonight
(April 29.86) and the comet is more obvious in this stack:
Nick.
On 29/04/2025 11:28, Thomas Lehmann via groups.io wrote:
Two nights earlier I have had a chance to observe whats left of the comet from
Weimar, Germany. The comet was at an altitude of only 5.5¡ã above horizon but I
gave it a try with my RASA 11" and ASI6200MC as conditions were exceptionally
good for my location.
The brightness near the head (green color channel) as measured within an
aperture of 3' is
2025 04 26.84 UT, m=9.8mag
and the tail extent is about 20' at P.A.=333¡ã
I am attaching the stacked image (12 minutes total exposure time) and an
inverted star trail subtracted and stronger smoothed image to highlight the
dust tail.
Out of curiosity I am attaching a plot of differential extinction measured from
stars near the comet as it is taken into account by my AIRTOOLS software
automatically.
CS
Thomas
Am Tue, 29 Apr 2025 07:42:48 +0100
schrieb "Nick James"<comets@...>:
Possible detection of C/2025 F2 (SWAN) on April 28.86:
A very noisy image taken in very bright twilight but there is a faint
patch of material at the right location.
Nick James. BAA
|
Re: Possible detection of C/2025 F2 on April 28.86
Dear all, from Schiaparelli Observatory the ex comet C2025 F2 near the NW Horizon two days ago in excellent sky condition Best Regards Andrea Aletti e Federico Bellini MPC204
Il giorno mar 29 apr 2025 alle ore 23:46 Nick James via <comets= [email protected]> ha scritto: Thomas,
Thanks. That's a great image. I've be plagued by distant cirrus near the
horizon to my northwest (probably aircraft contrails) so my transparency
has not been very good. I did have slightly better conditions tonight
(April 29.86) and the comet is more obvious in this stack:
Nick.
On 29/04/2025 11:28, Thomas Lehmann via wrote:
> Two nights earlier I have had a chance to observe whats left of the comet from
> Weimar, Germany. The comet was at an altitude of only 5.5¡ã above horizon but I
> gave it a try with my RASA 11" and ASI6200MC as conditions were exceptionally
> good for my location.
> The brightness near the head (green color channel) as measured within an
> aperture of 3' is
>? ? 2025 04 26.84 UT, m=9.8mag
> and the tail extent is about 20' at P.A.=333¡ã
>
> I am attaching the stacked image (12 minutes total exposure time) and an
> inverted star trail subtracted and stronger smoothed image to highlight the
> dust tail.
>
> Out of curiosity I am attaching a plot of differential extinction measured from
> stars near the comet as it is taken into account by my AIRTOOLS software
> automatically.
>
> CS
> Thomas
>
>
>> Am Tue, 29 Apr 2025 07:42:48 +0100
>> schrieb "Nick James"<comets@...>:
>>
>> Possible detection of C/2025 F2 (SWAN) on April 28.86:
>>
>>
>>
>> A very noisy image taken in very bright twilight but there is a faint
>> patch of material at the right location.
>>
>> Nick James. BAA
>>
>>
>>
>>
>>
>>
|
Re: Possible detection of C/2025 F2 on April 28.86
Thomas,
Thanks. That's a great image. I've be plagued by distant cirrus near the horizon to my northwest (probably aircraft contrails) so my transparency has not been very good. I did have slightly better conditions tonight (April 29.86) and the comet is more obvious in this stack:
Nick.
toggle quoted message
Show quoted text
On 29/04/2025 11:28, Thomas Lehmann via groups.io wrote: Two nights earlier I have had a chance to observe whats left of the comet from
Weimar, Germany. The comet was at an altitude of only 5.5¡ã above horizon but I
gave it a try with my RASA 11" and ASI6200MC as conditions were exceptionally
good for my location.
The brightness near the head (green color channel) as measured within an
aperture of 3' is
2025 04 26.84 UT, m=9.8mag
and the tail extent is about 20' at P.A.=333¡ã
I am attaching the stacked image (12 minutes total exposure time) and an
inverted star trail subtracted and stronger smoothed image to highlight the
dust tail.
Out of curiosity I am attaching a plot of differential extinction measured from
stars near the comet as it is taken into account by my AIRTOOLS software
automatically.
CS
Thomas
Am Tue, 29 Apr 2025 07:42:48 +0100
schrieb "Nick James"<comets@...>:
Possible detection of C/2025 F2 (SWAN) on April 28.86:
A very noisy image taken in very bright twilight but there is a faint
patch of material at the right location.
Nick James. BAA
|
Re: Comet of the century or pipe dream?
Hello Nico,
thanks for your comments and your simulations.
Regarding the discrepancies I think all depends on the setting of parameters which of course inhibit certain uncertainties. You'll see that the simulations I did from a simple selection of parameters with another tool showed a good agreement with the observations of 1402. Are they definite? Certainly not, but they show it is possible. I also do not really think that the perihelion date for 1402 can be so far off from March 25 as stated in the final paragraph in the respective chapter.
Concerning the descriptions which apparently do not seem to fit one also has to keep in mind that we deal with century-old or even millenia-old records which may have been altered, incorrectly recorded and transferred, or simply translated or interpreted wrongly. This is also outlined in the paper, where records are presented which contradict each other diametrically. We simply cannot take everything literally.
Also, we have to keep in mind that comets may behave not consistently, but this we all know. :-)
And, last but not least, and this should clearly be stated - this is a theory. We will probably not know until the end of this century if it is correct. I am positive, but who am I? :-)
Regards
Maik
--
"One cannot discover comets lying in bed." * Lewis Swift
________________________________________________________________________
|
Re: Comet of the century or pipe dream?
Hi Maik and Gary, That is a fascinating paper,?congratulation for the?huge work behind this ! I could not resist running simulations of the tails of the comet for the different passages mentioned in your paper. I point out that there is no individual adjustment of the comets (besides orbital parameters, brightness parameters and dust/gas ratio) on my simulations. For instance, all the comets generate periodic modulation of dust production rate but the associated striations only show up if the geometry and perihelion distance allows it.? The gif files can be opened with software like to be able to pause and extract single simulations. 1744:? already simulated on my website, very good match between simulation and observation 1402:? the simulation matches very well the observations, no comparison with the Hind orbit of the comet for which the simulation was no match at all. The only notable difference between simulation and reports I see is that, with perihelion date on March 25th calculated, the striation/multiple tails would probably only show up in the morning between 31st of March and 3rd of April, while they were reported on 26th and 27th of March. Does it seem possible that the perihelion date occurred a few days earlier ??
1032:? the mention that the comet of 1032 had a rayed tail does not seem to match, as with the proposed orbit the comet would have been observed well before the perihelion passage, hence way before any significant striation could have developed. Thus, I am a bit perplexed by this.
676: the simulation shows that the comet would have been rather ¡°small¡± in August and September and become ¡°great¡± only around October. The ¡°turning back of the tail¡± does not seem to match neither striation, nor curved tail, nor a shortening of the tail mentioned in the paper as the tail should have kept lengthening over the whole apparition. I am also a bit perplexed by the descriptions on this one too.
2097:? despite the excellent visibility, the fact that the earth will be near the orbital plane of the comet and the comet observed pre-perihelion, the comet should show much less interesting structure than in 1744. So probably another comet could be the actual comet of the century, I keep my fingers crossed that it would show up in a reasonable timespan!
Nicolas Lefaudeux
Le?mar. 29 avr. 2025 ¨¤?00:13, Qicheng Zhang via <qzalaska= [email protected]> a ¨¦crit?:
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 <adrien.coffinet2= [email protected]> 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
________________________________________________________________________
|
Re: Possible detection of C/2025 F2 on April 28.86
Two nights earlier I have had a chance to observe whats left of the comet from
Weimar, Germany. The comet was at an altitude of only 5.5¡ã above horizon but I
gave it a try with my RASA 11" and ASI6200MC as conditions were exceptionally
good for my location.
The brightness near the head (green color channel) as measured within an
aperture of 3' is
2025 04 26.84 UT, m=9.8mag
and the tail extent is about 20' at P.A.=333¡ã
I am attaching the stacked image (12 minutes total exposure time) and an
inverted star trail subtracted and stronger smoothed image to highlight the
dust tail.
Out of curiosity I am attaching a plot of differential extinction measured from
stars near the comet as it is taken into account by my AIRTOOLS software
automatically.
CS
Thomas
toggle quoted message
Show quoted text
Am Tue, 29 Apr 2025 07:42:48 +0100
schrieb "Nick James" <comets@...>:
Possible detection of C/2025 F2 (SWAN) on April 28.86:
A very noisy image taken in very bright twilight but there is a faint
patch of material at the right location.
Nick James. BAA
|
Possible detection of C/2025 F2 on April 28.86
Possible detection of C/2025 F2 (SWAN) on April 28.86:
A very noisy image taken in very bright twilight but there is a faint patch of material at the right location.
Nick James. BAA
|
Re: Comet of the century or pipe dream?
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
________________________________________________________________________
|
Re: Comet of the century or pipe dream?
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
________________________________________________________________________
|
Re: Comet of the century or pipe dream?
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 ________________________________________________________________________
|
Re: Comet of the century or pipe dream?
Finbarr, One quick note re William Edward Plummer; his dates are 1849-1928. hmm, you are right. The dates were later added by the editors, prior the final proof. I did not check these. Maik -- "One cannot discover comets lying in bed." * Lewis Swift ________________________________________________________________________
|
Re: Comet of the century or pipe dream?
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.
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...).
Qicheng
On Monday, April 28, 2025 at 07:56:03 a.m. MST, Maik Meyer <maik@...> wrote:
Sam, all,
many thanks to all for the congrats. It was quite an experience and fun to do this paper.
> In terms of validation prospects, we certainly don't have to wait until 2097 at least to confirm its existence. No
> comment is given in the paper on its nucleus size (rightly so) but if I were to ballpark-estimate it as about 50 km,
> then the nucleus would be detectable with JWST-Hale-Bopp-2022-style targeted observation as early as 2070-2075. I'm not
> sure how well its POS uncertainty is constrained by these orbit solutions (I'm guessing not very well?) and for a more
> typical present/next-gen wide field survey to detect it would probably take until the late 2070s to early 2080s
Maybe I am mistaken but from table 3 you see that the predicted perihelion date in 2097 varies by just one day for each
day we move away (back and forth) from the assumed 1402 perihelion date. If one is about to look for this comet 10 years
before (or even earlier) 2097 this small line of variation should be even smaller at such large distances. But even 2070
is stretch for me... I would be 100 by then. :-)
>? From another angle, I'm unable to determine the comet's Earth MOID anywhere, but something this large should
> theoretically have a pretty reliable meteor stream wherever its orbit does intersect. Is its MOID known or possible to
> determine?
It is 0.34 au and quite stable.
Regards
Maik
--
"One cannot discover comets lying in bed." * Lewis Swift
________________________________________________________________________
|
Re: Comet of the century or pipe dream?
Very interesting indeed.
?
One quick note re William Edward Plummer; his dates are 1849-1928.
?
Finbarr.
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Re: Comet of the century or pipe dream?
Sam, all, many thanks to all for the congrats. It was quite an experience and fun to do this paper. In terms of validation prospects, we certainly don't have to wait until 2097 at least to confirm its existence. No comment is given in the paper on its nucleus size (rightly so) but if I were to ballpark-estimate it as about 50 km, then the nucleus would be detectable with JWST-Hale-Bopp-2022-style targeted observation as early as 2070-2075. I'm not sure how well its POS uncertainty is constrained by these orbit solutions (I'm guessing not very well?) and for a more typical present/next-gen wide field survey to detect it would probably take until the late 2070s to early 2080s Maybe I am mistaken but from table 3 you see that the predicted perihelion date in 2097 varies by just one day for each day we move away (back and forth) from the assumed 1402 perihelion date. If one is about to look for this comet 10 years before (or even earlier) 2097 this small line of variation should be even smaller at such large distances. But even 2070 is stretch for me... I would be 100 by then. :-) From another angle, I'm unable to determine the comet's Earth MOID anywhere, but something this large should theoretically have a pretty reliable meteor stream wherever its orbit does intersect. Is its MOID known or possible to determine? It is 0.34 au and quite stable. Regards Maik -- "One cannot discover comets lying in bed." * Lewis Swift ________________________________________________________________________
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Erik
Danilo Pivato
