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Hi all,
I wanted to invite some discussion on this topic I've been wondering about for a bit: I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was published as a comet back in July, with four reports of cometary activity from X07 (H. Sato, T. Yoshimoto, and T. Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes. Meanwhile, my own simultaneous observations from X09 (0.43m) did not detect any sign of coma or tail even on extended exposures far outdoing the 15x50s (750s) exposure of N. Paul, the longest stack searching for cometary activity among the positives reported.
Similarly, no images that I've seen published by Seiichi Yoshida on aerith.net show even slight hints of coma or tail, even with significant SNR on the body. The 'comet's light curve has followed an asteroidal 5logr light curve from 8.6 AU from the Sun all the way through its 1.7 AU perihelion in October, as well as its peak magnitude of V=14 a few weeks ago.
I'm not sure what the three itelescope and one slooh observers saw, but I think I have to guess that they all made a mistake. Nothing I've seen firsthand (including the attached very high-SNR observation by a friend a few days ago) supports these claims, and I'm considering requesting the MPC to redesignate it as an A/ object.
~Sam
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Goodmorning,?
Well, I'm sharing the same thoughts.? I've been questioning this myself the first time i observed?this object:?
None of my observations showed any comet activity and the afrho values are always?very low. Especially when it's moving this fast i would expect to see some kind of tail or coma.?
Best Regards,
Mr. Pieter-Jan Dekelver Oudsbergen, Belgium observatorygromme@... Observatory Gr?mme - MPC: D09 – M09
On Tue, Dec 24, 2024 at 1:12?AM planetaryscience via <planetaryscience= [email protected]> wrote:
Hi all,
I wanted to invite some discussion on this topic I've been wondering about for a bit: I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was published as a comet back in July, with four reports of cometary activity from X07 (H. Sato, T. Yoshimoto, and T. Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes. Meanwhile, my own simultaneous observations from X09 (0.43m) did not detect any sign of coma or tail even on extended exposures far outdoing the 15x50s (750s) exposure of N. Paul, the longest stack searching for cometary activity among the positives reported.
Similarly, no images that I've seen published by Seiichi Yoshida on show even slight hints of coma or tail, even with significant SNR on the body. The 'comet's light curve has followed an asteroidal 5logr light curve from 8.6 AU from the Sun all the way through its 1.7 AU perihelion in October, as well as its peak magnitude of V=14 a few weeks ago.
I'm not sure what the three itelescope and one slooh observers saw, but I think I have to guess that they all made a mistake. Nothing I've seen firsthand (including the attached very high-SNR observation by a friend a few days ago) supports these claims, and I'm considering requesting the MPC to redesignate it as an A/ object.
~Sam
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Op 24-12-2024 om 0:12 schreef
planetaryscience via groups.io:
Hi all,
I wanted to invite some
discussion on this topic I've been wondering about for a bit:
I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was
published as a comet back in July, with four reports of
cometary activity from X07 (H. Sato, T. Yoshimoto, and T.
Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes.
Meanwhile, my own simultaneous observations from X09 (0.43m)
did not detect any sign of coma or tail even on extended
exposures far outdoing the 15x50s (750s) exposure of N. Paul,
the longest stack searching for cometary activity among the
positives reported.
Similarly, no images that
I've seen published by Seiichi Yoshida on aerith.net show even
slight hints of coma or tail, even with significant SNR on the
body. The 'comet's light curve has followed an asteroidal
5logr light curve from 8.6 AU from the Sun all the way through
its 1.7 AU perihelion in October, as well as its peak
magnitude of V=14 a few weeks ago.
I'm not sure what the three
itelescope and one slooh observers saw, but I think I have to
guess that they all made a mistake. Nothing I've seen
firsthand (including the attached very high-SNR
observation by a friend a few days ago) supports
these claims, and I'm considering requesting the MPC to
redesignate it as an A/ object.
~Sam
Hi Sam, all
It is definitely a (periodic) comet albeit one with very low
activity.
See this superb image obtained on December 19 by Nicolas Delanoy:
Note the soft tones that bring out the very faint coma/tail in the
magnified image.
Best regards,
??? Reinder
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Hello Sam ,
My observations from Nov. 04 and Dec. 12 seem to show to jets in
PA 200 and 340°?
but maybe it is just artefacts :
Best regards,
Francois
Le 24/12/2024 à 00:12, planetaryscience
via groups.io a écrit?:
Hi all,
I wanted to invite some
discussion on this topic I've been wondering about for a bit:
I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was
published as a comet back in July, with four reports of
cometary activity from X07 (H. Sato, T. Yoshimoto, and T.
Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes.
Meanwhile, my own simultaneous observations from X09 (0.43m)
did not detect any sign of coma or tail even on extended
exposures far outdoing the 15x50s (750s) exposure of N. Paul,
the longest stack searching for cometary activity among the
positives reported.
Similarly, no images that
I've seen published by Seiichi Yoshida on aerith.net show even
slight hints of coma or tail, even with significant SNR on the
body. The 'comet's light curve has followed an asteroidal
5logr light curve from 8.6 AU from the Sun all the way through
its 1.7 AU perihelion in October, as well as its peak
magnitude of V=14 a few weeks ago.
I'm not sure what the three
itelescope and one slooh observers saw, but I think I have to
guess that they all made a mistake. Nothing I've seen
firsthand (including the attached very high-SNR
observation by a friend a few days ago) supports
these claims, and I'm considering requesting the MPC to
redesignate it as an A/ object.
~Sam
--
Francois KUGEL
Observatoire chante-perdrix
Dauban
04150 BANON - France
MPC station # A77
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After checking, just artifact!
Le 24/12/2024 à 12:56, Francois KUGEL
via groups.io a écrit?:
Hello Sam ,
My observations from Nov. 04 and Dec. 12 seem to show to jets
in PA 200 and 340°?
but maybe it is just artefacts :
Best regards,
Francois
Le 24/12/2024 à 00:12,
planetaryscience via groups.io a écrit?:
Hi all,
I wanted to invite some
discussion on this topic I've been wondering about for a
bit: I don't think C/2024 M1 is actually a comet.
C/2024 M1 (ATLAS) was
published as a comet back in July, with four reports of
cometary activity from X07 (H. Sato, T. Yoshimoto, and T.
Prystavski) and W88 (N. Paul) - ~0.25 and ~0.5-m telescopes.
Meanwhile, my own simultaneous observations from X09 (0.43m)
did not detect any sign of coma or tail even on extended
exposures far outdoing the 15x50s (750s) exposure of N.
Paul, the longest stack searching for cometary activity
among the positives reported.
Similarly, no images that
I've seen published by Seiichi Yoshida on aerith.net show
even slight hints of coma or tail, even with significant SNR
on the body. The 'comet's light curve has followed an
asteroidal 5logr light curve from 8.6 AU from the Sun all
the way through its 1.7 AU perihelion in October, as well as
its peak magnitude of V=14 a few weeks ago.
I'm not sure what the three
itelescope and one slooh observers saw, but I think I have
to guess that they all made a mistake. Nothing I've seen
firsthand (including the attached very high-SNR
observation by a friend a few days ago) supports
these claims, and I'm considering requesting the MPC to
redesignate it as an A/ object.
~Sam
--
Francois KUGEL
Observatoire chante-perdrix
Dauban
04150 BANON - France
MPC station # A77
--
Francois KUGEL
Observatoire chante-perdrix
Dauban
04150 BANON - France
MPC station # A77
|
If one wants to be honest about what happens to any object with basically no atmosphere that gets close enough to the Sun to heat up its surface, they are all comets according to our definition of comets, even if we can't see the ejected material. That intense radiation heat is going to result in the ejection of material off the surface of such objects, the only limiting factor is whether our telescopes and cameras can see the objects that don't eject very much material so we humans can call them a comet or not. An asteroid is either an almost burnt-out comet or an object waiting to become a comet depending on its orbit. If one is lucky enough to catch one of these rather non-active objects when it happens to eject a little material due to the intense solar radiation falling on the right spot on its surface at the right time and get an image of that activity, then we humans call it a comet. Everything is subjective, even determining what is or isn't a comet, based on our own limitations of observation and the timing of such observations. As always, the truth is in the eye of the beholder.
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IMHO The level of activity is the important factor for the asteroid orbit study. If it is an object with so low activity that doesn’t affect observations is not a comet-like object. With no outburst and no non-gravitational effects. To recover objects after some oppositions the main factor to conclude that the object disappeared or simply is faint is if follows a comet like curve or the ejecta have influenced the orbit
If the object is in a comet like orbit at i>30 and high eccentricity is still an asteroid and there are many examples. Even if it could be considered a dead comet or near low emission comet.?
Following what you said I think many of that objects in that kind objects that doesn’t appear like originated in the MB or planetary disc, but in Oort Cloud, should be redefined or given a new classification.
Sincerely,
El El mar, 24 de diciembre de 2024 a la(s) 14:01, Mike Olason via <molason= [email protected]> escribió:
If one wants to be honest about what happens to any object with basically no atmosphere that gets close enough to the Sun to heat up its surface, they are all comets according to our definition of comets, even if we can't see the ejected material. That intense radiation heat is going to result in the ejection of material off the surface of such objects, the only limiting factor is whether our telescopes and cameras can see the objects that don't eject very much material so we humans can call them a comet or not. An asteroid is either an almost burnt-out comet or an object waiting to become a comet depending on its orbit. If one is lucky enough to catch one of these rather non-active objects when it happens to eject a little material due to the intense solar radiation falling on the right spot on its surface at the right time and get an image of that activity, then we humans call it a comet. Everything is subjective, even determining what is or isn't a comet, based on our own limitations of observation and the timing of such observations. As always, the truth is in the eye of the beholder.
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Mike - you are right that there's no clear objective dividing line between 'comet' and 'asteroid', and that the current definition is somewhat arbitrary, but this is still the definition we are working under until we can make some more quantifiable measure of activity level for solar system objects.
Regardless of if C/2024 M1 has a few kg/s of activity, its activity is clearly lower than a normal comet (below detectable levels) and should follow the precedent set by other damocloids. We are recording objects as comets based on activity, not based on feeling cometary based on their orbit alone, along with possible confirmation bias as I suspect happened here with the initial reports.
Reinder - Nicolas's observation does not seem to be perfectly stacked or may have some degree of (telescopic) coma. Surrounding stars clearly are fuzzier on the upper left than on the lower right direction and I suspect a sidereal stack would show each of them to have the same feature. Also, at the quoted 1.32" pixel scale this tail would be 8" long, which is quite a bit larger than other simultaneous observations rule out. Not to mention the fact that the observed tail seems to be of constant brightness and abruptly stop 8" from the nucleus, which is odd on its own.
~Sam
On Tuesday, December 24, 2024 at 03:01:40 PM EST, Mike Olason via groups.io <molason@...> wrote:
If one wants to be honest about what happens to any object with basically no atmosphere that gets close enough to the Sun to heat up its surface, they are all comets according to our definition of comets, even if we can't see the ejected material. That intense radiation heat is going to result in the ejection of material off the surface of such objects, the only limiting factor is whether our telescopes and cameras can see the objects that don't eject very much material so we humans can call them a comet or not. An asteroid is either an almost burnt-out comet or an object waiting to become a comet depending on its orbit. If one is lucky enough to catch one of these rather non-active objects when it happens to eject a little material due to the intense solar radiation falling on the right spot on its surface at the right time and get an image of that activity, then we humans call it a comet. Everything is subjective, even determining what is or isn't a comet, based on our own limitations of observation and the timing of such observations. As always, the truth is in the eye of the beholder.
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Hello to all,
Despite all the care I take for my shots, do not forget that the telescope used is only a connected telescope, powerful it is true but also has its flaws. For the magnitude calculation I am about consistent with other observers but you should not ask too much of it! What you see in the photo is probably an artifact so to take "with tweezers".?
Thank you and merry Christmas to all.
?
Bonjour à toutes et à tous,
Malgré tous les soins que je prends pour mes prises de vue, n'oubliez pas que le télescope utilisé n'est qu'un télescope connecté, performant il est vrai mais qui a aussi ses défauts. Pour le calcul de magnitude je suis à peu près cohérents avec les autres observateurs mais il ne faut pas trop lui en demandé ! Ce que vous voyez sur la photo est probablement un artefact donc à prendre "avec des pincettes".?
Merci et joyeux no?l à toutes et à tous.
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Nicolas,
?
Don't apologize, you put a lot of time and effort into collecting and processing these images, providing data for others who don't have such information to scrutinize. One can look at any image, any camera, any telescope, any software processing, anything to do with imaging comets and find numerous things to suggest the data is not perfect. Anyone who thinks any data is perfect is only fooling themselves. The only comet data that comes close to being perfect data is a single image that has had nothing done to it, totally raw data. Your data has created a lot of discussion which is a good thing, everyone should look at their own data and ask themselves just how realistic is that data after all the processing and everything else that has been done to their images. Then one can ask what the atmospheric conditions were when those images were collected from the surface of Planet Earth. Smog, thin clouds, haze, light pollution, aluminum oxide and the list goes on and on, a list that no one can answer but which produces or hides artifacts such as comas. Magnitude estimates, coma size, comas, tail lengths, everything to do with comet observations depends on so many variables that it is hard to decide if your images did show cometary activity, but it is also hard to say that they did not.
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Show quoted text
Nicolas,
?
Don't apologize, you put a lot of time and effort into collecting and processing these images, providing data for others who don't have such information to scrutinize. One can look at any image, any camera, any telescope, any software processing, anything to do with imaging comets and find numerous things to suggest the data is not perfect. Anyone who thinks any data is perfect is only fooling themselves. The only comet data that comes close to being perfect data is a single image that has had nothing done to it, totally raw data. Your data has created a lot of discussion which is a good thing, everyone should look at their own data and ask themselves just how realistic is that data after all the processing and everything else that has been done to their images. Then one can ask what the atmospheric conditions were when those images were collected from the surface of Planet Earth. Smog, thin clouds, haze, light pollution, aluminum oxide and the list goes on and on, a list that no one can answer but which produces or hides artifacts such as comas. Magnitude estimates, coma size, comas, tail lengths, everything to do with comet observations depends on so many variables that it is hard to decide if your images did show cometary activity, but it is also hard to say that they did not.
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reinder j bouma
Mike Olason