Comet 96P/Machholz in LASCO C3

[Calder]

This is the latest imagery from LASCO C3 showing a bright comet. If anyone was wondering, this is not C/2022 E3 (ZTF). It’s cool to see how bright it gets as it approaches the sun. Also, there’s some nice looking far side CMEs in there too.

 

 

Edited February 1, 2023 by Calder
Added updated image with CME

[Drax Spacex]

That comet is pulling a lot of g's!

[Sam Warfel]

3 hours ago, Drax Spacex said:

That comet is pulling a lot of g's!

Maybe it will fragment under the stress…

Would be fun to calculate just how many G’s it is experiencing. 

[Philalethes]

9 hours ago, Drax Spacex said:

That comet is pulling a lot of g's!

6 hours ago, Sam Warfel said:

Maybe it will fragment under the stress…

Would be fun to calculate just how many G’s it is experiencing. 

Maybe I'm missing something, but it didn't come closer to Sol than ~1.11 AU from what I read, so its acceleration due to gravity would be slightly less than that of the acceleration on Earth due to gravity; given that this acceleration is 0.006 m/s^2, that would be ~0.0006 g. Not a whole lot.

EDIT:

Never mind, I just read in the opening post that this is not C/2022 E3 (ZTF). Watching the footage in the gif it seemed very strange how a comet that passed at around the same distance as Earth does could ever look like that. In other words, disregard the above numbers, that's for C/2022 E3 (ZTF).

That one surely looks like it's indeed traveling a lot closer to Sol and experiencing a lot of acceleration. Not sure just how close it is, though.

Edited February 1, 2023 by Philalethes Bythos

[Calder]

10 hours ago, Drax Spacex said:

That comet is pulling a lot of g's!

Yeah, seems like it is. It would be interesting to know how many. Looks like it’s pulling off a sick drift around the sun right now. 😎

[Philalethes]

Found an article identifying this comet as 96P/Machholz; apparently it did fragment, but didn't disintegrate. Apparently it has a very short period of just 5.2 years, and there are quite a few papers and articles about it, such as this one from last time it was around. It even has it's own Wikipedia page.

According to that, it comes as close as ~0.124 AU at perihelion; I suspect this still isn't a lot of g's, though, and that it's primarily breaking apart because of the heat (which is the commonly cited reason for why comets fragment when near Sol).

The acceleration due to gravity at a given radius from a spherically symmetric object (which we can assume Sol is) is given by a = GM/r^2 where G is the gravitational constant, M is the mass of the object in question, and r is the given radius. As a simple preliminary calculation we can plug in the radius of Sol to see if it checks out with what tens of thousands of people have done before us, and since we get an answer of 274.2 m/s^2, we see that it does indeed check out, since 274 m/s^2 is the commonly cited value of the gravitational acceleration at the surface.

If we instead plug in the distance of the comet at perihelion, 0.124 AU, we get an acceleration of 0.386 m/s^2; as suspected, not a lot of g's at all, only a fraction of one. It corresponds to ~0.04 g, and is only ~0.238 of the gravitational acceleration on the surface of Luna.

Edited February 1, 2023 by Philalethes Bythos

[Calder]

24 minutes ago, Philalethes Bythos said:

Found an article identifying this comet as 96P/Machholz; apparently it did fragment, but didn't disintegrate. Apparently it has a very short period of just 5.2 years, and there are quite a few papers and articles about, such as this one from last time it was around. It even has it's own Wikipedia page.

According to that, it comes as close as ~0.124 AU at perihelion; I suspect this still isn't a lot of g's, though, and that it's primarily breaking apart because of the heat (which is the commonly cited reason for why comets fragment when near Sol).

The acceleration due to gravity at a given radius from a spherically symmetric object (which we can assume Sol is) is given by a = GM/r^2 where G is the gravitational constant, M is the mass of the object in question, and r is the given radius. As a simple preliminary calculation we can plug in the radius of Sol to see if it checks out with what tens of thousands of people have done before us, and since we get an answer of 274.2 m/s^2, we see that it does indeed check out, since 274 m/s^2 is the commonly cited value of the gravitational acceleration at the surface.

If we instead plug in the distance of the comet at perihelion, 0.124 AU, we get an acceleration of 0.386 m/s^2; as suspected, not a lot of g's at all, only a fraction of one. It corresponds to ~0.04 g, and is only ~0.238 of the gravitational acceleration on the surface of Luna.

Thanks! I tried to quickly find an article yesterday that could identify it but didn’t see anything. I guess I’m not really surprised that it’s not pulling many G’s. I think it mostly just looks fast on LASCO because there are many missing frames and it was at its closest approach to the sun.

[MissNeona]

4 hours ago, Calder said:

Yeah, seems like it is. It would be interesting to know how many. Looks like it’s pulling off a sick drift around the sun right now. 😎

The weird part is how the comet is now just frozen, suspended for a time lol.

 

Been like that many hours

 

 

[Drax Spacex]

4 hours ago, Philalethes Bythos said:

If we instead plug in the distance of the comet at perihelion, 0.124 AU, we get an acceleration of 0.386 m/s^2; as suspected, not a lot of g's at all, only a fraction of one. It corresponds to ~0.04 g, and is only ~0.238 of the gravitational acceleration on the surface of Luna.

You're right.   It sure looks like that comet is drifting and whipping around the Sun subject to extreme acceleration!  But perception and intuition may not always apply in an unfamiliar regime involving such incredibly high speeds and long distances.

m1=mass of Sun

m2=mass of comet

r is the distance between the center of the 2 masses.

F=G*m1*m2/r^2

combined with Newton's 2nd Law:

F=m2*a

m2*a=G*m1*m2/r^2

cancel out m2 from equation =>

a=G*m1/r^2

=(6.67E-11)(2.0E30)/(((0.124)(1.49E11))^2)

=0.391 m/s^2

A kinematic analysis observing the different positions of the comet (http://astro.vanbuitenen.nl/comet/96) could also be performed and would yield the same acceleration magnitude as a function of distance from the sun.  Of course, we'd need to know the 3D position not just a 2D projection as visible in LASCO.  

As a sanity check, we could calculate and compare the centripetal acceleration a=v^2/r given v=118 km/s and r=0.124AU at perihelion.  This would be using a simplified assumption of a circular orbit though we know the comet's actual trajectory is elliptical.  Calculating acceleration this way will not be exactly right, but it should be in the ballpark (within an order magnitude) for purposes of comparison.

a=(118,000m/s)^2/(0.124*1.5E11m)=0.75 m/s^2.

Edited February 1, 2023 by Drax Spacex
added 96P orbital trajectory link

[MissNeona]

23 minutes ago, Drax Spacex said:

You're right.   It sure looks like that comet is drifting and whipping around the Sun subject to extreme acceleration!  But perception and intuition may not always apply in an unfamiliar regime involving such incredibly high speeds and distances.

m1=mass of Sun

m2=mass of comet

r is the distance between the center of the 2 masses.

F=G*m1*m2/r^2

combined with Newton's 2nd Law:

F=m2*a

m2*a=G*m1*m2/r^2

cancel out m2 from equation =>

a=G*m1/r^2

=(6.67E-11)(2.0E30)/(((0.124)(1.49E11))^2)

=0.391 m/s^2

A kinematic analysis observing the different positions of the comet (http://astro.vanbuitenen.nl/comet/96) could also be performed and would yield the same acceleration magnitude as a function of distance from the sun.  Of course, we'd need to know the 3D position not just a 2D projection as visible in LASCO.  

As a sanity check, we could calculate and compare the centripetal acceleration a=v^2/r given v=118 km/s and r=0.124AU at perihelion.  This would be using a simplified assumption of a circular orbit though we know the comet's actual trajectory is elliptical.  Calculating acceleration this way will not be exactly right, but it should be in the ballpark (within an order magnitude) for purposes of comparison.

a=(118,000m/s)^2/(0.124*1.5E11m)=0.75 m/s^2.

What high speed?

It hasnt moved in over 8 hours lol

[Philalethes]

51 minutes ago, Drax Spacex said:

As a sanity check, we could calculate and compare the centripetal acceleration a=v^2/r given v=118 km/s and r=0.124A.U at perihelion.  This would be using a simplified assumption of a circular orbit though we know the comet's actual trajectory is parabolic.  Calculating acceleration this way will not be exactly right, but it should be in the ballpark (within an order magnitude) for purposes of comparison.

a=(118,000m/s)^2/(0.124*1.5E11m)=0.75 m/s^2.

Yeah, I considered doing this too, but decided it would be a lot less accurate since the approximation of a circular orbit near perihelion is quite tenuous for highly eccentric orbits; we can be fairly sure the first calculation is correct, so getting almost double that we can see just how tenuous.

As for the actual trajectory, that's indeed pretty hard to make out from the imagery. I think the curved shape of its tail can be misleading in that regard, since it gives an immediate apearance that the path is somehow curving just as much, but that doesn't seem to be the case. If you look at e.g. the second image in the OP, it seems like the tail is almost bending 45-60 degrees to the left from where it appears to originate from the comet. In contrast, when I traced out the path using only three points from the gif (not quite accurate, but since it doesn't appear to be curving that much it serves to illustrate it), I found that it definitely doesn't curve that much even throughout the entire gif:

27 minutes ago, MissNeona said:

What high speed?

It hasnt moved in over 8 hours lol

Are you watching it with a telescope? As per this ephemeris, you should be able to see it move quite clearly:

As you can see, both the RA and the declination are changing noticeably from day to day, and this would be continuous on a second-to-second basis (if you are using a telescope and it's got a tracking mechanism, you should be able to confirm this).

Edited February 1, 2023 by Philalethes Bythos

[MissNeona]

44 minutes ago, Philalethes Bythos said:

Yeah, I considered doing this too, but decided it would be a lot less accurate since the approximation of a circular orbit near perihelion is quite tenuous for highly eccentric orbits; we can be fairly sure the first calculation is correct, so getting almost double that we can see just how tenuous.

As for the actual trajectory, that's indeed pretty hard to make out from the imagery. I think the curved shape of its tail can be misleading in that regard, since it gives an immediate apearance that the path is somehow curving just as much, but that doesn't seem to be the case. If you look at e.g. the second image in the OP, it seems like the tail is almost bending 45-60 degrees to the left from where it appears to originate from the comet. In contrast, when I traced out the path using only three points from the gif (not quite accurate, but since it doesn't appear to be curving that much it serves to illustrate it), I found that it definitely doesn't curve that much even throughout the entire gif:

Are you watching it with a telescope? As per this ephemeris, you should be able to see it move quite clearly:

As you can see, both the RA and the declination are changing noticeably from day to day, and this would be continuous on a second-to-second basis (if you are using a telescope and it's got a tracking mechanism, you should be able to confirm this).

Lasco C3, a comet stopped around the sun and is now straightening position

 

Might prove a weird theory if it starts to descend quickly.

 

 

[Philalethes]

9 minutes ago, MissNeona said:

Lasco C3, a comet stopped around the sun and is now straightening position

I don't see anything like that on C3, and as far as I know 96P/Machholz is no longer visible there. It's already moved quite a bit since then. Its current position should be around here as per the ephemerides I've checked:

Overlaying C3 scaled to the approximate size of Sol in the above image (despite not being completely accurate since SOHO orbits 1.5 million km from Earth), we can get an idea about how far it's progressed by now:

[MissNeona]

28 minutes ago, Philalethes Bythos said:

I don't see anything like that on C3, and as far as I know 96P/Machholz is no longer visible there. It's already moved quite a bit since then. Its current position should be around here as per the ephemerides I've checked:

Overlaying C3 scaled to the approximate size of Sol in the above image (despite not being completely accurate since SOHO orbits 1.5 million km from Earth), we can get an idea about how far it's progressed by now:

How strange... be interesting to see if your as per ations were erroneous

 

Seems like it's hanging on to position, even adjusting head towards the sol core.

The universe is such an amazing thing.

https://soho.nascom.nasa.gov/data/realtime/c3/512/

[Philalethes]

1 hour ago, MissNeona said:

How strange... be interesting to see if your as per ations were erroneous

Seems like it's hanging on to position, even adjusting head towards the sol core.

The universe is such an amazing thing.

Those ephemerides are based on observations made by astronomers worldwide, and are updated continuously, so they are certainly not wrong themselves; in fact, I just cross-referenced with a live one, and the comet has actually progressed even further than shown in the first image, and is now right next to Eta Aquarii.

What could be off with regards to why it seems to be closer in C3 is that the central disc there doesn't actually correspond to the diameter of Sol, thus rendering the overlay I did wrong. I actually just took the time to check this, and that seems to indeed be the case; by looking at the relative distances observed between the stars Iota Capricorni and Theta Capricorni, as well as Nu Aquarii and Eta Aquarii (since these are relatively easy to identify in the C3 imagery), the central circular portion of the image that's blotted out does in fact not seem to correspond to the diameter of Sol at all, and is much larger. This fully accounts for the difference between the overlay I made and what is actually observed on the latest imagery. No point in remaking it since the comet is still within view on C3, then.

Also, given this information, it's now clear that the comet is exactly where you'd expect it to be from the ephemerides (right next to Eta Aquarii, which is the star at the very top border of the latest C3 image, in the middle on the left-right axis). Great, objective reality is still working as expected, phew.

As for the notion that it's "frozen", I don't see what you mean. The latest image is from 15:54, so if you mean that it simply hasn't been updated since then, it would indeed appear "frozen" (since it's the same image), but it sounds like you're implying that the comet has somehow stopped in its orbit. If you look at the SOHO Movie Theater in the left-hand menu of the link you just provided (this), and select C3, highest resolution, and yesterday to today, you'll see that the comet was constantly moving until the last image in that series (from 14:54, one hour earlier than the latest from the other link), and that it also moved from 14:54 to 15:54 as well when you compare the two.

In other words, the comet has been constantly moving for as long as it's been observed, just as is expected, and if it suddenly halted in its orbit it would be an astronomical miracle that astronomers worldwide, both professionals and amateurs alike, would immediately start flooding the web with information about. The universe is indeed quite interesting, but for as long as we've been observing it carefully it's been following the same laws of physics as always, and I doubt it's going to stop doing that anytime soon.

Edited February 1, 2023 by Philalethes Bythos

[Drax Spacex]

1 hour ago, Philalethes Bythos said:

...the central circular portion of the image that's blotted out does in fact not seem to correspond to the diameter of Sol at all, and is much larger. 

The Sun I believe is represented in LASCO imagery by the white circle, not the blotting out occulting disk.

A down-to-earth analogy - the maximum acceleration incurred by comet 96P as it rounded the Sun at perihelion would be the same acceleration that a person would feel on the outside of a 10-meter radius merry-go-round rotating with a tangential velocity of 2 m/s.  I miss high school physics!

Edited February 1, 2023 by Drax Spacex

[Philalethes]

37 minutes ago, Drax Spacex said:

The Sun I believe is represented in LASCO imagery by the white circle, not the blotting out occulting disk.

That makes perfect sense. I already did establish that it can't possibly be the disk, but the size of the white circle fits perfectly.

38 minutes ago, Drax Spacex said:

A down-to-earth analogy - the maximum acceleration incurred by comet 96P as it rounded the Sun at perihelion would be the same acceleration that a person would feel on the outside of a 10-meter radius merry-go-round rotating with a tangential velocity of 2 m/s.  I miss high school physics!

Yes, that would be about right indeed; great comparison, brings it into a perspective that's more relatable.

[SpaceWeather5464]

Will it be visible to the naked eye or fade away?

[Philalethes]

17 minutes ago, SpaceWeather5464 said:

Will it be visible to the naked eye or fade away?

Good question. Right now you won't be able to see it since it's right next to Sol, obviously, but even at its very closest approach it would only have had an apparent magnitude of 2-3. Now, a bit past that, it's already 4-5. Beyond 6-7 and you won't be able to see it with the naked eye, so the question is whether or not it reaches that before moving far enough away to be visible in the evening or morning. It also depends on how much light pollution there is wherever you're observing from; the more pollution, the lower the limiting magnitude.

If I were to guess I'd say it won't be possible to see with the naked eye in most places due to its trajectory not being conducive to it. If it were moving away from or closer to the horizon with respect to Sol, it could've been possible to see it in some places before it becomes too faint, but it seems to me like it will set roughly at sunset in most places, especially in the northern hemisphere. I could be wrong, I guess we'll find out after it moves a bit more.

[Solarflaretracker200]

Does anyone know where I can see this comet? Like I know it’s not visible now, but when it does get visible?

[Jesterface23]

43 minutes ago, Solarflaretracker200 said:

Does anyone know where I can see this comet? Like I know it’s not visible now, but when it does get visible?

It is visible, just not on the SWPC's site. (those issues)

Here is the latest imagery,
https://iswa.ccmc.gsfc.nasa.gov/IswaSystemWebApp/index.jsp?i_1=15&l_1=40&t_1=270&w_1=500&h_1=500&s_1=0_1_120_3

Edited February 2, 2023 by Jesterface23

[Solarflaretracker200]

1 minute ago, Jesterface23 said:

It is visible, just not on the SWPC's site. (those issues)

Here is the latest imagery,
https://iswa.ccmc.gsfc.nasa.gov/IswaSystemWebApp/index.jsp?i_1=15&l_1=40&t_1=270&w_1=500&h_1=500&s_1=2023-02-01 20:54:00.0_1_90_3

No, I’m sorry I mean like when can it be seen to the naked eye or in the view of a telescope. (Like I can see it in person)

[Sam Warfel]

This one? No. Comet ZTF can be seen through a telescope

[Solarflaretracker200]

2 minutes ago, Sam Warfel said:

This one? No. Comet ZTF can be seen through a telescope

Wait, is it visible now? Because I thought it isn’t. 

[Calder]

1 minute ago, Solarflaretracker200 said:

Wait, is it visible now? Because I thought it isn’t. 

This comet isn’t but C/2022 E3 (ZTF) is. Saw it this morning using my XT8. It was pretty faint and wasn’t visible to the naked eye unfortunately. It’s possible that it might be visible to the naked eye in areas with no light pollution, but the moon is also making it hard to see.