APOD: Comet Leonard behind JWST Launch Plume (2021 Dec 27)

[johnnydeep]

https://apod.nasa.gov/apod/ap181013.html
https://apod.nasa.gov/apod/ap181012.html
https://apod.nasa.gov/apod/ap171224.html
https://apod.nasa.gov/apod/ap120329.html

Ok, so those rocket plumes and trails have varied appearances, but none look like a sphere. The sphere is harder to explain. But I did read Pon's post above, and that explanation at least seems reasonable.

[alter-ego]

https://apod.nasa.gov/apod/ap181013.html
https://apod.nasa.gov/apod/ap181012.html
https://apod.nasa.gov/apod/ap171224.html
https://apod.nasa.gov/apod/ap120329.html

Ok, so those rocket plumes and trails have varied appearances, but none look like a sphere. The sphere is harder to explain. But I did read Pon's post above, and that explanation at least seems reasonable.

The links are all for LEO launches. I speculate that plume dynamics could be different at the higher JWST altitude of 1400km where the atmosphere is less dense. Also, the particular JWST release conditions / details may be different?

Oh, the last link is for sounding rockets that didn't go beyond the ionosphere.

[Pon]

https://apod.nasa.gov/apod/ap181013.html
https://apod.nasa.gov/apod/ap181012.html
https://apod.nasa.gov/apod/ap171224.html
https://apod.nasa.gov/apod/ap120329.html

Ok, so those rocket plumes and trails have varied appearances, but none look like a sphere. The sphere is harder to explain. But I did read Pon's post above, and that explanation at least seems reasonable.

The links are all for LEO launches. I speculate that plume dynamics could be different at the higher JWST altitude of 1400km where the atmosphere is less dense. Also, the particular JWST release conditions / details may be different?

Oh, the last link is for sounding rockets that didn't go beyond the ionosphere.

These are also first to second stage soon after launch. The "JWST" in the photo would be the Upper Stage with maneuver aiming for elliptical orbit with apogee at L2. You can see very similar plume in some of the photos above but the surrounding shock looks different from the JWST shot, likely due to difference in altitude as you mention.

Here's another pic from the same location, also with Ariane 5 rocket (but different trajectory).
https://apod.nasa.gov/apod/ap140212.html

I shot this myself 7 years ago (so you're welcome to assume I "fake" both of these pic). You can see that the rocket looked rather similar, except JWST is much brighter (probably illuminated by sunlight). That sighting was what inspired me to try out the shot on Chrismas, although there was no way I could predict how they will exactly line up.

Note that the circular plasma envelope did not last very long. It fade away rather quickly. You can see them changing in this image sequence:

shots sequence

[alter-ego]

Pon - Thank you very much for the time and care you've spent following the posts, clarifying and correcting our understanding of your images, and sharing your many years of experience recording and figuring out the plume(s). For us, one APOD sometimes does not tell enough information, and for several of us, we want to make sense what's going on. Consequently, we sometimes don't understand and make wrong assumptions. It is rare that an APOD contributor dives in like you have here. It's been a breath of fresh air. Your patience, helpful nature and detailed presentation have removed all questions about your image being "fake". For me, this APOD has set a new bar that I'd like to see more often.
Thanks again and keep up the great work!

[Ann]

I didn't follow all the technical back and forth discussion above, and maybe I missed it, but what's the significance of the plume being surrounded by an almost perfect sphere, seemingly centered on the point of the cone of what I would call the plume proper?

Click to view full size image

As it is on the Earth, so it is in heaven, right, Johnny?

My point is that the circular JWST plume with the exhaust inside it looks much like planetary nebula Abell 30.

Born-again planetary nebula Abell 30. Photo: Astroian.

---

Born-again planetary nebula Abell 30. Main image: X-ray: ESA/XMM-Newton; optical: NSF/NOAO/KPNO; inset: NASA/CXC/IAA-CSIC/M. Guerrero et al; optical: NASA/STScI

---

The thing about Abell 30 is that it is a "born-again" planetary nebula. Let's call it a two-stage nebula. First there was this episode where the pre-planetary "red giant-about to become a white dwarf" shed its outer layers and turned them into a perfectly spherical nebula. Then, at stage two, the central white dwarf acted up again and lit up the inner regions of the nebula by producing a new burst of energy.

Shouldn't we assume that this is what has happened here, too? Or at least, shouldn't we assume that the large circular (or spherical) plume was produced slightly before the inner fan-shaped exhaust, or at least that it was produced through another mechanism?

Ann

[Pon]

Pon - Thank you very much for the time and care you've spent following the posts, clarifying and correcting our understanding of your images, and sharing your many years of experience recording and figuring out the plume(s). For us, one APOD sometimes does not tell enough information, and for several of us, we want to make sense what's going on. Consequently, we sometimes don't understand and make wrong assumptions. It is rare that an APOD contributor dives in like you have here. It's been a breath of fresh air. Your patience, helpful nature and detailed presentation have removed all questions about your image being "fake". For me, this APOD has set a new bar that I'd like to see more often.
Thanks again and keep up the great work!

Full disclosure is that I know RJN personally. He was my thesis advisor after all. Currently, I'm working as a science communicator and astronomy outreach in Thailand. With my background in astrophotography, I had in the past, and still occasionally help RJN on identifying whether some of the APOD submissions were "fake". There were many that I helped weeded out, some that I wished he were to ask me first, and admittedly some that I totally missed. We have discussed at lengths many times the definition of "real" and "fake" when it comes to APOD images. I even presented a talk about that very topic for APOD at AAS conference.

So when I submitted this image and told him that it was a "single shot", he has little doubt to the authenticity of it and knows exactly what I mean by it (unlike many submissions where we had to fish for the real response by photographers). At this point I should mention he has rejected many of my submissions so it's not like I got any special treatment. He definitely does not play favorites in this regard.

So as you can see, providing scientific explanations to phenomena just happens to coincide with many of my interests. (Not the least of which because my old advisor asked me to respond to asterisk) People should be more skeptical like you all have. I don't really mind it at all.

[johnnydeep]

Pon - Thank you very much for the time and care you've spent following the posts, clarifying and correcting our understanding of your images, and sharing your many years of experience recording and figuring out the plume(s). For us, one APOD sometimes does not tell enough information, and for several of us, we want to make sense what's going on. Consequently, we sometimes don't understand and make wrong assumptions. It is rare that an APOD contributor dives in like you have here. It's been a breath of fresh air. Your patience, helpful nature and detailed presentation have removed all questions about your image being "fake". For me, this APOD has set a new bar that I'd like to see more often.
Thanks again and keep up the great work!

Amen to that! And for the record, I, for one, never thought the shot was faked, only that it needed further explanation of it's unusual appearance. Unusual to me anyway - my posting history will show that I find a lot of stuff unusual looking

[johnnydeep]

As it is on the Earth, so it is in heaven, right, Johnny?

My point is that the circular JWST plume with the exhaust inside it looks much like planetary nebula Abell 30.
...

The thing about Abell 30 is that it is a "born-again" planetary nebula. Let's call it a two-stage nebula. First there was this episode where the pre-planetary "red giant-about to become a white dwarf" shed its outer layers and turned them into a perfectly spherical nebula. Then, at stage two, the central white dwarf acted up again and lit up the inner regions of the nebula by producing a new burst of energy.

Shouldn't we assume that this is what has happened here, too? Or at least, shouldn't we assume that the large circular (or spherical) plume was produced slightly before the inner fan-shaped exhaust, or at least that it was produced through another mechanism?

Ann

Maybe, maybe not. Not all things that look the same have similar causes. Is a rocket flying through increasingly rarefied air by ejecting high speed plasma in a single direction dynamically equivalent to a star sitting still in space (though admittedly also flying through the interstellar medium) ejecting matter in all directions? On the surface of it, I'd bet against it, but what do I know.

[neufer]

Pon - Thank you very much for the time and care you've spent following the posts, clarifying and correcting our understanding of your images, and sharing your many years of experience recording and figuring out the plume(s). For us, one APOD sometimes does not tell enough information, and for several of us, we want to make sense what's going on. Consequently, we sometimes don't understand and make wrong assumptions. It is rare that an APOD contributor dives in like you have here. It's been a breath of fresh air. Your patience, helpful nature and detailed presentation have removed all questions about your image being "fake". For me, this APOD has set a new bar that I'd like to see more often.
Thanks again and keep up the great work!

Amen to that! And for the record, I, for one, never thought the shot was faked, only that it needed further explanation of it's unusual appearance. Unusual to me anyway - my posting history will show that I find a lot of stuff unusual looking

Until someone addresses my concern about an Ariane rocket that stopped firing over East Africa
at an altitude of 1,000 km being clearly visible in the skies over Thailand I remain a skeptic.

[Chris Peterson]

Pon - Thank you very much for the time and care you've spent following the posts, clarifying and correcting our understanding of your images, and sharing your many years of experience recording and figuring out the plume(s). For us, one APOD sometimes does not tell enough information, and for several of us, we want to make sense what's going on. Consequently, we sometimes don't understand and make wrong assumptions. It is rare that an APOD contributor dives in like you have here. It's been a breath of fresh air. Your patience, helpful nature and detailed presentation have removed all questions about your image being "fake". For me, this APOD has set a new bar that I'd like to see more often.
Thanks again and keep up the great work!

Amen to that! And for the record, I, for one, never thought the shot was faked, only that it needed further explanation of it's unusual appearance. Unusual to me anyway - my posting history will show that I find a lot of stuff unusual looking :)

Until someone addresses my concern about an Ariane rocket that stopped firing over East Africa
at an altitude of 1,000 km being clearly visible in the skies over Thailand I remain a skeptic. :?

We're not seeing a firing rocket in this image, though. We're seeing some kind of exhaust event, like a fuel dump.

[neufer]

Until someone addresses my concern about an Ariane rocket that stopped firing over East Africa
at an altitude of 1,000 km being clearly visible in the skies over Thailand I remain a skeptic.

We're not seeing a firing rocket in this image, though. We're seeing some kind of exhaust event, like a fuel dump.

It may just be me but that seems like an awful waste of Ariane rocket fuel (when the JWST has so little to spare).

(Do you think the JWST mirrors appreciated the Ariane rocket fuel shpritz )

[Pon]

Pon - Thank you very much for the time and care you've spent following the posts, clarifying and correcting our understanding of your images, and sharing your many years of experience recording and figuring out the plume(s). For us, one APOD sometimes does not tell enough information, and for several of us, we want to make sense what's going on. Consequently, we sometimes don't understand and make wrong assumptions. It is rare that an APOD contributor dives in like you have here. It's been a breath of fresh air. Your patience, helpful nature and detailed presentation have removed all questions about your image being "fake". For me, this APOD has set a new bar that I'd like to see more often.
Thanks again and keep up the great work!

Amen to that! And for the record, I, for one, never thought the shot was faked, only that it needed further explanation of it's unusual appearance. Unusual to me anyway - my posting history will show that I find a lot of stuff unusual looking

Until someone addresses my concern about an Ariane rocket that stopped firing over East Africa
at an altitude of 1,000 km being clearly visible in the skies over Thailand I remain a skeptic.

I think I've explained just that over and over again by this point. But in any case, here's another round:

You're not seeing the BURN of the rocket. You're seeing the exhaust. Rockets propels forward by dumping a lot of gas behind it. Do you think those gas just disappear? The ones up to the point of separation would've followed the exact same trajectory. Then those gas that are 1,000 km up would be in the sun, reflecting off sunlight and everything.

In other words, you're seeing the rocket "contrails".

The booster is also extremely hot and still venting some plasma, as can be evident by the spiraling in the close-up shots.

I understand the urge to remain skeptical until satisfactory explanations is provided. However, there's still the fact that it was observed by millions of people here in Thailand.

Here's a video clip: https://www.facebook.com/NARITpage/vide ... 7188021160
And here's another post about the plume, which is followed by thousands of comments from mobile phone captures from the public: https://www.facebook.com/NARITpage/phot ... 110341464/

So for the case like this where there's already an overwhelming evidence, whether we could explain it or not is besides the point. For me, there's also the fact that I saw it with my own two eyes. I saw how it lit up the sky, how it moves and drifted, and how it faded. So it's indeed REAL, let's just establish that fact. Then we can move on to the explanations.

Unless you want to claim there was another rocket... You're welcome to provide the evidence of another launch from another facility closer to Southeast Asia. But this rocket would have to be launched closer (since you don't believe rockets can be seen thousands of miles away. Maybe it was launch by Iran or India?), that happens to fly over Thailand exactly the same time JWST did. Also, it needed to have an elliptical trajectory with apogee somewhere in the night side of the Earth... let's just say L2 for the sake of simplicity, because from the ground here it went straight up and never return, unlike other satellites and spent rocket stages.

But then there's also another sightings of rocket-like object over the same location 7 years ago that also happen about 40 minutes after another Ariane 5 launch: https://apod.nasa.gov/apod/ap140212.htm What would be the odds of random rocket launches happen to fly over Thailand the same time window after Ariane 5 twice in a row?

[Chris Peterson]

Until someone addresses my concern about an Ariane rocket that stopped firing over East Africa
at an altitude of 1,000 km being clearly visible in the skies over Thailand I remain a skeptic. :?

We're not seeing a firing rocket in this image, though. We're seeing some kind of exhaust event, like a fuel dump.

It may just be me but that seems like an awful waste of Ariane rocket fuel (when the JWST has so little to spare).

Other than the fact that it's a different kind of fuel. And the JWST tanks are at 100%. And there's no transfer system.

(Do you think the JWST mirrors appreciated the Ariane rocket fuel shpritz :?: )

First and second stages both use oxygen and hydrogen. Doesn't seem like a problem. In any case, the mirrors are folded and protected, and I doubt that the designers overlooked the launch events.

[neufer]

I, for one, never thought the shot was faked, only that it needed further explanation of it's unusual appearance. Unusual to me anyway - my posting history will show that I find a lot of stuff unusual looking

Until someone addresses my concern about an Ariane rocket that stopped firing over East Africa
at an altitude of 1,000 km being clearly visible in the skies over Thailand I remain a skeptic.

You're not seeing the BURN of the rocket. You're seeing the exhaust. Rockets propels forward by dumping a lot of gas behind it. Do you think those gas just disappear? The ones up to the point of separation would've followed the exact same trajectory. Then those gas that are 1,000 km up would be in the sun, reflecting off sunlight and everything.

In other words, you're seeing the rocket "contrails".

The lingering ice/water vapor rocket "contrails" would ,indeed, have followed the exact same trajectory
... but only at about half the Ariane's velocity due to an effective exhaust velocity of 4360 m/s:

<<The second stage is on top of the main stage and below the payload. Ariane 5ECA uses the ESC (Étage Supérieur Cryotechnique — Cryogenic Upper Stage), which is fueled by liquid hydrogen and liquid oxygen [with an effective exhaust velocity of 4360 m/s].>>

The booster is also extremely hot and still venting some plasma, as can be evident by the spiraling in the close-up shots.

• I don't know about your "visible plasma" thing.

However, I am guessing now that the exhaust plume, itself, might well have turned into one giant expanding "smoke ring" to account for the large sunlight excited "bubble" you observed (and perhaps to some extent even the bright convergent center).

I understand the urge to remain skeptical until satisfactory explanations is provided. However, there's still the fact that it was observed by millions of people here in Thailand.

Here's a video clip: https://www.facebook.com/NARITpage/vide ... 7188021160
And here's another post about the plume, which is followed by thousands of comments from mobile phone captures from the public: https://www.facebook.com/NARITpage/phot ... 110341464/

So for the case like this where there's already an overwhelming evidence, whether we could explain it or not is besides the point. For me, there's also the fact that I saw it with my own two eyes. I saw how it lit up the sky, how it moves and drifted, and how it faded. So it's indeed REAL, let's just establish that fact. Then we can move on to the explanations.>>

Yes, you indeed:

• 1) saw it evolve with your own eyes
  2) knew exactly when it occurred and
  3) knew which direction you were looking

I was lacking all that information... hence the confused emoji :

But then there's also another sightings of rocket-like object over the same location 7 years ago that also happen about 40 minutes after another Ariane 5 launch: https://apod.nasa.gov/apod/ap140212.html What would be the odds of random rocket launches happen to fly over Thailand the same time window after Ariane 5 twice in a row?

I would have interpreted that Ariane 5 launch as a second stage that was actively firing over the skies of Thailand
and not as one that stopped firing over East Africa at an altitude of 1,000 km.

I remain confused about many aspects of what I am seeing in your beautiful image but
I no longer question that is the result of the Ariane 5 second stage that launched the JWST.
(My apologies if you took offense.)

[neufer]

Click to play embedded YouTube video.

We're not seeing a firing rocket in this image, though. We're seeing some kind of exhaust event, like a fuel dump.

It may just be me but that seems like an awful waste of Ariane rocket fuel (when the JWST has so little to spare).

Other than the fact that it's a different kind of fuel. And the JWST tanks are at 100%. And there's no transfer system.

Not really what I meant... but apparently, there were good reasons not to boost JWST any more than they did in order to insure that the JWST did not have to turn around to slow down (see video).

(Do you think the JWST mirrors appreciated the Ariane rocket fuel shpritz )

First and second stages both use oxygen and hydrogen. Doesn't seem like a problem. In any case, the mirrors are folded and protected, and I doubt that the designers overlooked the launch events.

The JWST mirrors are folded and totally unprotected from any fuel dump from the Ariane second stage as it casually separated itself at a walking pace. The Ariane second stage was indeed left with extra fuel but it is capable of multiple ignitions and could have disposed of its remaining fuel by igniting it and sending it 4 km/sec in the opposite direction of the JWST. (I wonder, in fact, if that is exactly what we are observing in the APOD?)

[Chris Peterson]

Click to play embedded YouTube video.

It may just be me but that seems like an awful waste of Ariane rocket fuel (when the JWST has so little to spare).

Other than the fact that it's a different kind of fuel. And the JWST tanks are at 100%. And there's no transfer system.

Not really what I meant... but apparently, there were good reasons not to boost JWST any more than they did in order to insure that the JWST did not have to turn around to slow down (see video).

(Do you think the JWST mirrors appreciated the Ariane rocket fuel shpritz :?: )

First and second stages both use oxygen and hydrogen. Doesn't seem like a problem. In any case, the mirrors are folded and protected, and I doubt that the designers overlooked the launch events.

The JWST mirrors are folded and totally unprotected from any fuel dump from the Ariane second stage as it casually separated itself at a walking pace. The Ariane second stage was indeed left with extra fuel but it is capable of multiple ignitions and could have disposed of its remaining fuel by igniting it and sending it 4 km/sec in the opposite direction of the JWST. (I wonder, in fact, if that is exactly what we are observing in the APOD?)

A burn would have contaminated the area with water. Pure oxygen and pure hydrogen should have no effect on the surface of the mirrors at all.

The colors we are seeing completely argue against a burn. This is just gas being illuminated and stimulated by sunlight.

[neufer]

(Do you think the JWST mirrors appreciated the Ariane rocket fuel shpritz )

First and second stages both use oxygen and hydrogen. Doesn't seem like a problem. In any case, the mirrors are folded and protected, and I doubt that the designers overlooked the launch events.

The JWST mirrors are folded and totally unprotected from any fuel dump from the Ariane second stage as it casually separated itself at a walking pace. The Ariane second stage was indeed left with extra fuel but it is capable of multiple ignitions and could have disposed of its remaining fuel by igniting it and sending it 4 km/sec in the opposite direction of the JWST. (I wonder, in fact, if that is exactly what we are observing in the APOD?)

A burn would have contaminated the area with water.

Pure oxygen and pure hydrogen should have no effect on the surface of the mirrors at all.

Pure oxygen, pure hydrogen and water would have been dissociated
by solar UV into reactive atomic oxygen, atomic hydrogen & hydroxyl (OH).

<<Atomic oxygen is very reactive, as the single atoms of oxygen tend to quickly bond with nearby molecules. On Earth's surface, it does not exist naturally for very long, but in outer space, the presence of plenty of ultraviolet radiation results in a low Earth orbit atmosphere in which 96% of the oxygen occurs in atomic form.>>

<<One airglow mechanism is when an atom of nitrogen combines with an atom of oxygen to form a molecule of nitric oxide (NO). In the process, a photon is emitted. This photon may have any of several different wavelengths characteristic of nitric oxide molecules. The free atoms are available for this process, because molecules of nitrogen (N₂) and oxygen (O₂) are dissociated by solar energy in the upper reaches of the atmosphere and may encounter each other to form NO. Other chemicals that can create air glow in the atmosphere are hydroxyl (OH), atomic oxygen (O), sodium (Na), and lithium (Li).>>

But a delayed minor burn off to the side (north to Thailand?) could have prevented water contamination.

The colors we are seeing completely argue against a burn.
This is just gas being illuminated and stimulated by sunlight.

The blue "bubble" itself could well be remnants of a prior burn.

The white central cone, however, continues to remain a mystery to me.

[Chris Peterson]

First and second stages both use oxygen and hydrogen. Doesn't seem like a problem. In any case, the mirrors are folded and protected, and I doubt that the designers overlooked the launch events.

The JWST mirrors are folded and totally unprotected from any fuel dump from the Ariane second stage as it casually separated itself at a walking pace. The Ariane second stage was indeed left with extra fuel but it is capable of multiple ignitions and could have disposed of its remaining fuel by igniting it and sending it 4 km/sec in the opposite direction of the JWST. (I wonder, in fact, if that is exactly what we are observing in the APOD?)

A burn would have contaminated the area with water.

Pure oxygen and pure hydrogen should have no effect on the surface of the mirrors at all.

Pure oxygen, pure hydrogen and water would have been dissociated
by solar UV into reactive atomic oxygen, atomic hydrogen & hydroxyl (OH).

<<Atomic oxygen is very reactive, as the single atoms of oxygen tend to quickly bond with nearby molecules. On Earth's surface, it does not exist naturally for very long, but in outer space, the presence of plenty of ultraviolet radiation results in a low Earth orbit atmosphere in which 96% of the oxygen occurs in atomic form.>>

<<One airglow mechanism is when an atom of nitrogen combines with an atom of oxygen to form a molecule of nitric oxide (NO). In the process, a photon is emitted. This photon may have any of several different wavelengths characteristic of nitric oxide molecules. The free atoms are available for this process, because molecules of nitrogen (N₂) and oxygen (O₂) are dissociated by solar energy in the upper reaches of the atmosphere and may encounter each other to form NO. Other chemicals that can create air glow in the atmosphere are hydroxyl (OH), atomic oxygen (O), sodium (Na), and lithium (Li).>>

And a delayed minor burn off to the side (over Thailand?) could have prevented water contamination.

The colors we are seeing completely argue against a burn.
This is just gas being illuminated and stimulated by sunlight.

The blue "bubble" itself could well be remnants of a prior burn.

The white central cone, however, continues to remain a mystery to me.

Gold is not reactive with atomic oxygen. This is one reason that some surfaces are coated with gold on low-Earth satellites, where erosion by atomic oxygen of many metal surfaces can be a major problem.

In any case, the point is this: whatever they did above Thailand, you can bet it was part of the mission plan and scheduled to the second, and not something that put the probe at risk. By design.

[Pon]

I remain confused about many aspects of what I am seeing in your beautiful image but
I no longer question that is the result of the Ariane 5 second stage that launched the JWST.
(My apologies if you took offense.)

I'm not offended. As I said it's perfectly ok to be skeptical. However, having been repeatedly rejected despite numerous evidences and explanations provided does get old after a while. Kind of giving me this new Netflix movie "Don't look up" vibe. After a while I just want to move on from the "did it really happen?" question onto "How can we explain it?". Forgive me if I got a little impatient.

But now that we can move on to the more important question, I don't have all the answers yet but I have some thoughts.

The conical shaped plume has much whiter coloration than the bluish hue of spiral shape and the "envelope". This suggest to me that it's scattered by sunlight. This even made more sense if you compare it with the Ariane 5 pic 7 years ago where the white cone was missing. That time I took it right before sunrise so the rocket would've come from the night side of the Earth. This time I took it right after sunset, so the rocket came from the day side, hence the cone is lit by the sun.

The bluish hue both times started out normal, then started spiraling more and more outward. This suggest to me a rocket engine out of control started spinning and venting whatever was left that was still hot enough to become ionized. As the engine kept spinning more plasma was being vent and the spiral kept expanding. After a while the vent stopped but you can still see the previous spiral kept on expanding, leaving a gap in the center.

In any case, it is clear to me in both instances that what I observed was no longer active. It's just spent rocket/fuel coasting along in their trajectory. They drift similar to a satellite meaning no apparent acceleration. Except for the case of JWST it has a rather unique apparent "escape trajectory" (actually elliptical) from my perspective. This made perfect sense if we consider that JWST is heading for L2 in the night side. You would have to "depart" LEO roughly at this position in your orbit.

The lingering ice/water vapor rocket "contrails" would ,indeed, have followed the exact same trajectory
... but only at about half the Ariane's velocity due to an effective exhaust velocity of 4360 m/s:

You are right about this. But even at half the velocity it would still put the vapor trails all the way to the Moon's orbit. This would still put it on a very similar elliptical orbit with the same perigee as JWST. The angle would just be slightly different. And you can kind of see that the "plume" trails behind the glowing upper stage engine a bit.

The "envelope" however is a bit harder to explain. What I witness was that it glowed and dimmed rather quickly. And instead of trailing like the rest of the things I saw, it only appeared at that moment and just faded. To me this suggests it's atmospheric in origin. My guess would be the shocked front as the rocket exhaust from the burn earlier expanded and impacted into the atmosphere. It does also seem to be direction-dependent (brighter towards the front), as oppose to the plasma vent that is perfectly symmetrical.

But again, that's just my best guess so far.

[Pon]

In any case, the point is this: whatever they did above Thailand, you can bet it was part of the mission plan and scheduled to the second, and not something that put the probe at risk. By design.

I believe by the time I observed it, JWST was already kilometers away from the spent upper stage/exhaust. What the upper stage does at this point would not have impacted JWST in any way.

[alter-ego]

Pon - Thank you very much for the time and care you've spent following the posts, clarifying and correcting our understanding of your images, and sharing your many years of experience recording and figuring out the plume(s). For us, one APOD sometimes does not tell enough information, and for several of us, we want to make sense what's going on. Consequently, we sometimes don't understand and make wrong assumptions. It is rare that an APOD contributor dives in like you have here. It's been a breath of fresh air. Your patience, helpful nature and detailed presentation have removed all questions about your image being "fake". For me, this APOD has set a new bar that I'd like to see more often.
Thanks again and keep up the great work!

Amen to that! And for the record, I, for one, never thought the shot was faked, only that it needed further explanation of it's unusual appearance. Unusual to me anyway - my posting history will show that I find a lot of stuff unusual looking

Until someone addresses my concern about an Ariane rocket that stopped firing over East Africa
at an altitude of 1,000 km being clearly visible in the skies over Thailand I remain a skeptic.

**************************************************

Sounds like you don't question the visibility anymore. I'm posting this anyway for those curious.

**************************************************

The fact the image was taken 10 min later is the deal maker. Unfortunately, lacking the tracking data during this 10-minute interval, I had to make assumptions that I wasn't all that happy with.
 >> Independently calculated the Alt/Az and nadir Lat/Long of the JWST/plume location assuming the plume(s) tracked with it, and
 >> Compared these results with Stellarium's Alt/Az of the imaged plume(s)

>> Results:
 - Calculated [Alt, Az] @ 12:57 UT = [23°,232°] Note: Plume trajectory looks reasonable,but appears to lag JWST location (make sense).
 - Stellarium [Alt, Az] @ 12:57 UT = [17°,237°]
 - Estimated NASA Tracking Altitude (km) @ 12:57 UT = 4792 km
 - Estimated NASA Tracking Distance from East African coast @ 12:57 UT = 3508 km
 - Google Map great circle distance from East African coast @ 12:57 UT ≈ 3525 km
 → Google Map shows plume nadir [Long, Lat] ≈ [4°S, 71°E]
  

 
>> Details:
• Critical JWST data source: https://www.youtube.com/watch?v=7nT7JGZMbtM

 
 - At elapsed times 24.0, 25.0, 26.0 and 27.0 minutes I used the tracking parameters from the first panel to calculate the plume location
   and altitude (km)
 - I used the 3rd panel (map) to replicate the projected ground track into Google Maps between Africa's East coast and the plume location

• I used Google maps to:
 - Set up the great circle arcs that connect the following two locations to the final calculated plume location (projected onto Earth) @ 12:57 UT
   The locations are the African East coast location @ 12:47 UT and Pon's location at Chiang Mai, Thailand
 - Determine the predicted plume azimuth wrt Pon, and
 - Iteratively solve for the plume-image altitude (degrees) by adjusting arc lengths / angles until the predictions
   were consistent with tracking data.

• As mentioned, Stellarium provided the imaged plume alt/az

• Assumptions
 - Plume(s) followed the same trajectory Altitude (km) and Distance (km) tracks as JWST
 - Tracking data is very accurate.
   → Estimated corrections for velocity and position changes by calculating best-fit quadratic equations for both distance and altitude (km)
  
>> Solving for plume visibility at 12:57 UT:
 - Solution independent of image alt/az.
 - One solution for a fixed altitude (km) above Earths surface.
 - Predicted altitude (degrees) is higher, and azimuth is further east. Suggests the plume(s) lag JWST.
 - Additional calculations assuming a constant average velocity (linear best fits, not quadratic) predict plume(s) are further lagging the JWST.

Pretty convincing I'd say.

[Pon]

Amen to that! And for the record, I, for one, never thought the shot was faked, only that it needed further explanation of it's unusual appearance. Unusual to me anyway - my posting history will show that I find a lot of stuff unusual looking

Until someone addresses my concern about an Ariane rocket that stopped firing over East Africa
at an altitude of 1,000 km being clearly visible in the skies over Thailand I remain a skeptic.

**************************************************

Sounds like you don't question the visibility anymore. I'm posting this anyway for those curious.

**************************************************

The fact the image was taken 10 min later is the deal maker. Unfortunately, lacking the tracking data during this 10-minute interval, I had to make assumptions that I wasn't all that happy with.
 >> Independently calculated the Alt/Az and nadir Lat/Long of the JWST/plume location assuming the plume(s) tracked with it, and
 >> Compared these results with Stellarium's Alt/Az of the imaged plume(s)

>> Results:
 - Calculated [Alt, Az] @ 12:57 UT = [23°,232°] Note: Plume trajectory looks reasonable,but appears to lag JWST location (make sense).
 - Stellarium [Alt, Az] @ 12:57 UT = [17°,237°]
 - Estimated NASA Tracking Altitude (km) @ 12:57 UT = 4792 km
 - Estimated NASA Tracking Distance from East African coast @ 12:57 UT = 3508 km
 - Google Map great circle distance from East African coast @ 12:57 UT ≈ 3525 km
 → Google Map shows plume nadir [Long, Lat] ≈ [4°S, 71°E]
  
Google Map - JWST, Plume at 1257 UT.jpg
 
>> Details:
• Critical JWST data source: https://www.youtube.com/watch?v=7nT7JGZMbtM
NASA JWST Tracking Panels.jpg
 
 - At elapsed times 24.0, 25.0, 26.0 and 27.0 minutes I used the tracking parameters from the first panel to calculate the plume location
   and altitude (km)
 - I used the 3rd panel (map) to replicate the projected ground track into Google Maps between Africa's East coast and the plume location

• I used Google maps to:
 - Set up the great circle arcs that connect the following two locations to the final calculated plume location (projected onto Earth) @ 12:57 UT
   The locations are the African East coast location @ 12:47 UT and Pon's location at Chiang Mai, Thailand
 - Determine the predicted plume azimuth wrt Pon, and
 - Iteratively solve for the plume-image altitude (degrees) by adjusting arc lengths / angles until the predictions
   were consistent with tracking data.

• As mentioned, Stellarium provided the imaged plume alt/az

• Assumptions
 - Plume(s) followed the same trajectory Altitude (km) and Distance (km) tracks as JWST
 - Tracking data is very accurate.
   → Estimated corrections for velocity and position changes by calculating best-fit quadratic equations for both distance and altitude (km)
  
>> Solving for plume visibility at 12:57 UT:
 - Solution independent of image alt/az.
 - One solution for a fixed altitude (km) above Earths surface.
 - Predicted altitude (degrees) is higher, and azimuth is further east. Suggests the plume(s) lag JWST.
 - Additional calculations assuming a constant average velocity (linear best fits, not quadratic) predict plume(s) are further lagging the JWST.

Pretty convincing I'd say.

Very nice work!

Do you happen to know how much the plume lag behind JWST? It would be nice to point out exactly where JWST should be in the image in relation to the more visible plume.

[alter-ego]

...
Very nice work!

Do you happen to know how much the plume lag behind JWST? It would be nice to point out exactly where JWST should be in the image in relation to the more visible plume.

Well, I'm unable to estimate the lag accurately, but after an additional analysis constraint and more complete trajectory calculation, I'd say the location accuracy is as good as it gets. The one added constraint is I assumed the JWST trajectory intersects the plume. I did not make any assumptions about JWST's location along the trajectory. The result is better than I expected. The cumulative uncertainties originating from the quadratic-fit functions, and a 10-minute extrapolation resulted in roughly ± 4.5° uncertainty along its trajectory. JWST's calculated position leads the plume by ~400km.
 

[alter-ego]

...
Very nice work!

Do you happen to know how much the plume lag behind JWST? It would be nice to point out exactly where JWST should be in the image in relation to the more visible plume.

Well, I'm unable to estimate the lag accurately, but after an additional analysis constraint and more complete trajectory calculation, I'd say the location accuracy is as good as it gets. The one added constraint is I assumed the JWST trajectory intersects the plume. I did not make any assumptions about JWST's location along the trajectory. The result is better than I expected. The cumulative uncertainties originating from the quadratic-fit functions, and a 10-minute extrapolation resulted in roughly ± 4.5° uncertainty along its trajectory. JWST's calculated position leads the plume by ~400km.
 
JWST Leading Plume &amp; Trajectory.jpg

For completeness, I checked JPL HORIZONS and, surprisingly, the JWST trajectory is in the data base for times ≥ 2021-12-25 12:49:09.184. This range covers Po's image. The local risetime (including refraction) = 12:53 UT. Given the assumptions, limited data and required extrapolation in my brute-force calculation approach, I'm very happy with my final achieved accuracy.

In addition to the HORIZONS trajectory data, I did make two corrections to the image in my last post:
• Location annotation was wrong. It was a carryover from a case I did where I additionally constrained JWST location to be in the plume.
• Corrected small Lat / Long errors in Po's location
 

 
• I'm curious about why HORIZONS locates JWST apparently lagging behind the plume.
  I guess not knowing the plumes' dynamics, it's not clear where JWST should be.
• The slope difference is most likely related due to the fit-function overestimating JWST's altitude (km).

Although the exercise was new and instructive, I doubt I'd have done it if I first found HORIZONS had the data.