Re: Is C/2024 M1 really a comet?
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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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