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'Once-in-a-lifetime' stellar occultation by 29P visible from central Europe next February
On the evening of 2025 February 05, the nucleus of Comet 29P will occult a 13th magnitude star, the shadow of which will cross France, northern Italy, etc. as shown on the map below courtesy of Mike Kretlow.
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The track is predicted to cross the observatories of Jean-Fran?ois Soulier (L27) and Fran?ois Kugel (A77) at Dauban, Haute-Provence: a 'once-in-a-lifetime' opportunity for these observers.
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Below is the current ephemeris as predicted by JPL Horizons.
Nearer the time we shall update the orbit to obtain a more accurate prediction.
This is a very favourable occultation event so, given clear skies, it has great potential.
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Richard Miles
BAA
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Summary of 2023?2024 apparition of 29P
Here's a short summary of the 2023?2024 apparition now that 29P is approaching a solar elongation of 25° and will be in conjunction with the Sun for almost 3 months before reappearing in the morning sky about September 15.
Am showing both this apparition and the previous 2022?2023 one below. This latest apparition has received particularly good coverage. Thanks everyone! We have had 42 observers contributing images and measurements. The following lists the number of observing runs contributed by observers. One or two observers were lucky to catch the outburst coma brightening so these have contributed some multiple datapoints to the above plot.? More reports later. Richard BAA MISSION 29P |
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Re: Excellent coverage of 29P's outbursts continue - Strange lightcurve this apparition
开云体育Thanks Eliot for those creative suggestions. I think we can rule out this pattern as one created by chance alone – We have seen 29P before do this – Locked into a series of mostly strong events or mostly weak ones. ? Given it needs a crust of some sort to hold pressure, it seems reasonable to suppose that in some areas the crust will be stronger or weaker on average and so the intensity of an eruption would then be a sort of proxy for the strength of the crust at the location of the vent. Vents must seal quickly after an eruption. Strong events show the 57-day periodicity, presumed its rotation period, which means they can recharge only after a day-night cycle but the mini-outbursts happen every 3–10 days or so, which means there are lots more weak sources. There is also a continual leakage of volatiles and dust presumably where the crust is hardly able to hold any pressure and where eruptions therefore can’t happen: quite a range of terrain no doubt. ? The strongest event we have seen was the quadruple eruption of 2021 September followed by another strong event on 2021 October 23 after which even the mini-outbursts virtually stopped for almost 60 days and then they slowly came back but no strong ones were seen. So maybe the pressure reservoir in the nucleus can be drained of gas available to drive eruptions. ? The tail-off in brightness is really a function of the measuring aperture size rather than an intrinsic property of the nucleus. ? If group members would like to see what the last 22 years (20 apparitions worth) of eruption intensity looks like when folded on a 57.68-day rotation period, have a look at the end of the following webpage: I have just updated the plot – it now spans 8000 days. ? A very strange object indeed. ? Cheers, Richard ? From: [email protected] <[email protected]> On Behalf Of Eliot Herman
Sent: Thursday, June 13, 2024 8:23 PM To: [email protected] Subject: Re: [29P-ml] Excellent coverage of 29P's outbursts continue - Strange lightcurve this apparition ? This is such beautiful data….? Is there any chance the vent moves position using Iceland as an idea as the venting moves laterally along a fault there are larger and smaller episodes. Ceres might argue otherwise for a vent being stationary, but if there is faulting the vent may move through weaker and stronger crusts with a weaker crust allowing for a more continuous light venting where a stronger crust section requires a larger buildup before the rapid (as observed this year in a wonderful observation) making for a massive rise and quick fall (note how quickly the large vents fall v weaker events that tail off more slowly. If 29P looks like a small moon of Saturn or Uranus it might have many cracks or faults… although these have tidal heating which begs the question what is going with 29P. ? Figure is amazing. ? eliot ? ? ? From: [email protected] <[email protected]> on behalf of Richard Miles via groups.io <rmiles.btee@...> Thanks everyone who has continue to supply observations even though the 'comet' is now closer than 43° to the Sun. |
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Re: Excellent coverage of 29P's outbursts continue - Strange lightcurve this apparition
开云体育This is such beautiful data….? Is there any chance the vent moves position using Iceland as an idea as the venting moves laterally along a fault there are larger and smaller episodes. Ceres might argue otherwise for a vent being stationary, but if there is faulting the vent may move through weaker and stronger crusts with a weaker crust allowing for a more continuous light venting where a stronger crust section requires a larger buildup before the rapid (as observed this year in a wonderful observation) making for a massive rise and quick fall (note how quickly the large vents fall v weaker events that tail off more slowly. If 29P looks like a small moon of Saturn or Uranus it might have many cracks or faults… although these have tidal heating which begs the question what is going with 29P. ? Figure is amazing. ? eliot ? ? ? From:
[email protected] <[email protected]> on behalf of Richard Miles via groups.io <rmiles.btee@...> Thanks everyone who has continue to supply observations even though the 'comet' is now closer than 43° to the Sun. |
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Excellent coverage of 29P's outbursts continue - Strange lightcurve this apparition
Thanks everyone who has continue to supply observations even though the 'comet' is now closer than 43° to the Sun.
The website is once again up to date with so far 1038 epochs of photometry are shown plotted. Here is what it now looks like and I pose a question: Why the change in behaviour since early April? Richard |
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29P has been constant in brightness during the past 6 days
Rarely do we see 29P so constant in brightness when faint and when it should be continuing to fade further.
It's current absolute magnitude is R(1,1,0) = 8.56 but if it was truly quiescent at its 'floor' level it would be 9.00 (equivalent to 17.35R), so the coma is actually close to 2x brighter than its lowest possible value and yet its magnitude is very stable. This means that it is able to outgas at a rate that is about 2x greater than normal, which might mean it continues to leak pressure from beneath the crust and so prevent a strong outburst. The strongest outburst of 2024 was on March 24, which was 60 days ago, i.e. almost exactly one rotation earlier, so what we can be measuring is the leakage from the vent that was responsible for the outburst of March 24 and which is losing pressure at an enhanced rate preventing a further strong outburst from this particular source. All very interesting! Do keep observing to check for any mini-outbursts. Here are the latest photometry: Clear skies, Richard? 0029P ? ? ? ? C2024 05 17.86750 08 17 12.97 +20 00 49.1 ? ? ? ? ?16.84R ? ? ?Z31 5.45" (5.65") 120s r Miles 0029P ? ? ? ? C2024 05 17.86920 08 17 13.04 +20 00 49.2 ? ? ? ? ?16.89R ? ? ?Z31 0029P ? ? ? ? C2024 05 18.23462 08 17 23.55 +20 00 01.1 ? ? ? ? ?16.82R ? ? ?718 5.11" (5.47") 10x60s Clear Wiggins 0029P ? ? ? ? C2024 05 18.69653 08 17 37.39 +19 58 59.8 ? ? ? ? ?16.95R ? ? ?K91 5.45" (5.65") 120s r Miles 0029P ? ? ? ? C2024 05 18.69824 08 17 37.44 +19 58 59.5 ? ? ? ? ?16.90R ? ? ?K91 0029P ? ? ? ?KC2024 05 18.84631 08 17 41.82 +19 58 38.6 ? ? ? ? ?16.63R ? ? ?L27 5.96" (6.70") Soulier 0029P ? ? ? ?KC2024 05 18.88206 08 17 42.80 +19 58 33.2 ? ? ? ? ?16.70R ? ? ?L27 0029P ? ? ? ?KC2024 05 18.91148 08 17 43.71 +19 58 29.1 ? ? ? ? ?16.65R ? ? ?L27 0029P ? ? ? ? C2024 05 18.86990 08 17 42.49 +19 58 35.0 ? ? ? ? ?16.86R ? ? ?Z31 5.45" (5.65") 120s r Wooding St Marys 0029P ? ? ? ? C2024 05 18.88151 08 17 42.83 +19 58 33.4 ? ? ? ? ?16.78R ? ? ?Z31 0029P ? ? ? ? C2024 05 18.88320 08 17 42.88 +19 58 33.2 ? ? ? ? ?16.90R ? ? ?Z31 0029P ? ? ? ? C2024 05 19.87193 08 18 12.41 +19 56 19.6 ? ? ? ? ?16.90R ? ? ?Z31 5.45" (5.65") 120s r Miles 0029P ? ? ? ? C2024 05 19.87363 08 18 12.46 +19 56 19.2 ? ? ? ? ?17.01R ? ? ?Z31 0029P ? ? ? ? C2024 05 20.71114 08 18 37.80 +19 54 26.1 ? ? ? ? ?16.88R ? ? ?K91 5.45" (5.65") 120s r Miles 0029P ? ? ? ? C2024 05 20.71284 08 18 37.85 +19 54 25.9 ? ? ? ? ?16.93R ? ? ?K91 0029P ? ? ? ? C2024 05 20.86315 08 18 42.41 +19 54 03.6 ? ? ? ? ?16.76R ? ? ?M02 5.13" (5.41") R 240s Genebriera 0029P ? ? ? ? C2024 05 20.86624 08 18 42.46 +19 54 02.8 ? ? ? ? ?16.86R ? ? ?M02 0029P ? ? ? ? C2024 05 20.86933 08 18 42.52 +19 54 02.2 ? ? ? ? ?16.81R ? ? ?M02 0029P ? ? ? ? C2024 05 20.87242 08 18 42.68 +19 54 02.9 ? ? ? ? ?17.00R ? ? ?M02 0029P ? ? ? ? C2024 05 20.87863 08 18 42.86 +19 54 01.8 ? ? ? ? ?17.06R ? ? ?M02 0029P ? ? ? ? C2024 05 20.88172 08 18 42.99 +19 54 00.2 ? ? ? ? ?16.93R ? ? ?M02 0029P ? ? ? ? C2024 05 20.88481 08 18 43.06 +19 54 00.6 ? ? ? ? ?16.82R ? ? ?M02 0029P ? ? ? ? C2024 05 20.88790 08 18 43.15 +19 54 01.1 ? ? ? ? ?16.96R ? ? ?M02 0029P ? ? ? ? C2024 05 20.91355 08 18 43.64 +19 53 58.5 ? ? ? ? ?16.90R ? ? ?M09 5.55" (6.11") 8x210s r Dekelver 0029P ? ? ? ? C2024 05 21.17075 08 18 51.66 +19 53 22.4 ? ? ? ? ?16.84R ? ? ?718 5.11" (5.47") 10x60s Clear Wiggins 0029P ? ? ? ? C2024 05 21.87182 08 19 13.32 +19 51 44.5 ? ? ? ? ?16.90R ? ? ?Z31 5.45" (5.65") 120s r Miles 0029P ? ? ? ? C2024 05 21.87351 08 19 13.37 +19 51 44.3 ? ? ? ? ?16.89R ? ? ?Z31 0029P ? ? ? ? C2024 05 22.17686 08 19 22.56 +19 51 02.5 ? ? ? ? ?16.94R ? ? ?718 5.11" (5.47") 10x60s Clear Wiggins 0029P ? ? ? ? C2024 05 22.69508 08 19 38.88 +19 49 50.8 ? ? ? ? ?16.91R ? ? ?K91 5.45" (5.65") 120s r Miles 0029P ? ? ? ? C2024 05 23.87047 08 20 15.77 +19 47 03.8 ? ? ? ? ?16.90R ? ? ?Z31 5.45" (5.65") 120s r Wooding St Marys ----- end ----- |
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Re: When can we expect another strong outburst from 29P?
开云体育Good luck, Joan. I am away foir 4 days on holiday now. R. ? From: [email protected] <[email protected]> On Behalf Of Joan Genebriera
Sent: Sunday, May 19, 2024 9:28 PM To: [email protected] Subject: Re: [29P-ml] When can we expect another strong outburst from 29P? ? I will do my best to get pictures. We currently have a storm for tonight but hopefully tomorrow will be possible. ? Joan ? El 19/5/2024 I will do my best to get pictures. We currently have a storm for tonight but hopefully tomorrow will be possible a les 20:25, Richard Miles via groups.io ha escrit:
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Re: When can we expect another strong outburst from 29P?
开云体育I will do my best to get pictures. We
currently have a storm for tonight but hopefully tomorrow will be
possible.
Joan
El 19/5/2024 I will do my best to get
pictures. We currently have a storm for tonight but hopefully
tomorrow will be possible a les 20:25, Richard Miles via groups.io
ha escrit:
The next 21 days are especially favourable for observing 29P as your first target of the night once the sky darkens in the evening. |
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When can we expect another strong outburst from 29P?
The next 21 days are especially favourable for observing 29P as your first target of the night once the sky darkens in the evening.
Currently the 'comet' is approaching a solar elongation of 63°, which will be down to 45° after another 3 weeks. Although the Moon is approaching full in 4-5 days, it will be a long distance from the comet and after this time it will not have risen when you image 29P so you should be able to image by stacking several frames. It is currently approaching magnitude 17.0R and is surrounded by quite a strong coma. That magnitude translates to an absolute R(1,1,0) magnitude of 8.70 so this is still some 0.5-0.6 mag brighter than its lowest possible brightness before which a strong outburst would be expected. So it's anyone's guess as to whether we will see a strong outburst in the next 21 days - we may just see a few more mini-outbursts as it let's off pressure. Clear skies, Richard |
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29P: Four mini-outbursts in the space of 10 days!
We are now up to 950 epochs of data this 2023-24 apparition.
I encourage observers to make an extra effort to raise the number to >1000 epochs especially whilst the object is exhibiting a cumulative brightening as one mini-outburst follows another in quick succession. Its solar elongation is now <69° so not many weeks left to go. Here's the latest lightcurve: Notice the frequent mini-outbursts in the last month or so. It gives the impression that the activity is increasing but most of what we are seeing is an accumulation of discrete short-lived eruptions that happen so often that the inner coma is not able to fade to a more quiescent level. Richard |
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29P News update + JWST
Thanks to the various observers who are obtaining good coverage of this object before it reaches too low a solar elongation to be observable.
It is currently at 72 degrees from the Sun. There have been mini-outbursts on April 30 and May 4, and a possible very weak one on May 7 (to be confirmed). Other news is that I have been exploring the James Webb Space Telescope observations that have been made public a couple of months ago. More time-resolved data will be available next January. The data are quite astonishing! JWST is like no other instrument in terms of its capabilities. The IFU was used to take an array of 30x30 pixels, each measuring about 0.1 arcsec in size. That means it covers an area on the sky almost 8000 km square around the nucleus and each pixel is about 250 km across at the comet. The total exposure time was 2100 s and it recorded 940 slices of its spectrum (in each pixel!) spanning from 0.6 micron to 5.3 micron wavelength. So you end up with 940 FITS files spread across the spectrum with each image being a 30x30 array. You can play a movie of it using the the SAO DS9 analysis software for multi-dimensional FITS images. My first comments are that the CO gas coma is very different in shape and extent to that of the CO2 gas coma, which sits closer in to the nucleus and which may not be directly associated with the outbursts. Next is to integrate the slices of the spectrum that do not include any gas emission lines to see what the dust coma looks like say towards the shorter and towards the longer wavelengths. It will also be interesting to compare JWST with MISSION 29P data around the same epoch. Eric Watkins obtained a 0.5-m image about 2 hours before the JWST observations and Cai Stoddard-Jones and myself between us have six 2.0-m images taken about 8 hours after JWST. Cai also obtained 3 exposures 3 days earlier with the same telescope (Faulkes South). By chance, JWST imaged when the nucleus was rather quiet, 6 days after a 0.7-mag? mini-outburst: just over a day later there followed a much stronger outburst. Richard |
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Re: New paper: Explanation of the Anomalous Outburst Activity of Comet 29P/Schwassmann–Wachmann 1: The Hypothesis about the Existence of Large Satellites
开云体育Wayne, ? Sorry I earlier missed answering some of the points you have raised. ? No translation afaik. ? No satellites from the JWST observations afaik. Interestingly those image data should now be available to the general public given that 12 months have now passed, so I shall have to go searching for them. There is some CO and CO2 measurements in the coma where they seem to be completely different from which I assume that they were released from different outbursts – may have to go back through our data to better understand the JWST results. ? There’s no other system known that is similar to what they are hypothesizing about. It would have to be a temporary meta-stable condition. ? There will have to be an update of the 2.0-m photometry for 29P so we have a better orbit. But we need more images during quiescence to increase the timebase. Remember that if the orbit is changed then it takes quite a time to elapse before the change can be measured.- Anyway, we know that 29P has been doing what it does for more than 100 years, which if there has been an outburst every 15 days on average means an awful lot of collisions. ? This ‘publication’ might never have been subject to proper review. I should add that despite its apparent disagreement with the observational evidence it may still have got published because it is an academic mathematical model that is not based on reality but instead on some imagined scenario. So technically it might be considered to be valid. Personally, I am not keen on mathematicians modelling unreal physical situations? - I would have wanted them to say how their model stacks up against the observations. ? Richard ? From: [email protected] <[email protected]> On Behalf Of Wayne Hawley
Sent: Wednesday, April 24, 2024 9:23 AM To: [email protected] Subject: Re: [29P-ml] New paper: Explanation of the Anomalous Outburst Activity of Comet 29P/Schwassmann–Wachmann 1: The Hypothesis about the Existence of Large Satellites ? Richard, ? I have not found a translation of the full text so cannot see if they have a prediction for the size or orbital periods of the proposed satellites.? ? Did the imaging from the James Webb identify any other objects that could be satellites.? ? Contact, or approach close enough to be within the ejecta would degrade the orbit of any satellite and this would mean that this could not be sustainable in the longer term.? ? You recently had a rework on the position of 29P to provide better occultation predictions. Is there anything from this reworking of the data based on the 2m images from the LCO to suggest a wobble in the position of 29P ? ? Regards ? Wayne 0790 1212761
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Re: New paper: Explanation of the Anomalous Outburst Activity of Comet 29P/Schwassmann–Wachmann 1: The Hypothesis about the Existence of Large Satellites
P.S. I should have added this:
Eric has made a very good point about photometry revealing orbiting satellites, which inevitably will undergo mutual occultations and eclipses with the main nucleus. This is perhaps the strongest argument against the Russian hypothesis in that our observations involve a lot (and I mean a lot!) of continuous monitoring sometimes with large telescopes and we have NEVER detected an attenuation of the lightcurve. Richard |
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Re: New paper: Explanation of the Anomalous Outburst Activity of Comet 29P/Schwassmann–Wachmann 1: The Hypothesis about the Existence of Large Satellites
开云体育Dear 础苍诲谤é et al. It is certainly an hypothesis worth examining and thinking about. There isn’t a version of the full text available at present although I have requested one through ResearchGate. You say the contacts are rare but, I suppose, their frequency would depend on how many satellites there could be and what size each of them is. We have been fortunate that between 2022 December and 2023 May, there took place a rare series of stellar occultations by the nucleus of 29P, of which FIVE events were successfully observed as positive disappearances of the star, two events having multiple chords. On 2022 December 19 there were 4 chords and on 2023 January 28 there were 7 chords. This means there have been a total of 15 separate occultation tracks that have probed the immediate neighboured around the nucleus and not a single attenuation other than the 100% blocking by the nucleus has been detected. The Russian authors will have written their paper not knowing about all of these observations. It is possible that the satellites are too small to detect but in such a chaotic scenario involving satellite collisions or near-collisions there should be some sort of debris disk detectable – none has been found. Another argument against their hypothesis is the sheer number of eruptions we now have data on. Since the start of our intensive monitoring in 2014 March, i.e. 10 years of data, we have detected 91 strong outbursts and 127 mini-outbursts. Another good argument against this hypothesis is the nature in which ALL these eruptions develop. An explosive model can be fitted to the data of the rise to maximum. Here, material appears to be ejected into space in a very short-lived (several minutes) event and the debris cloud appears to be inflated by gas, the more intense the eruption, the more gas there is to expand the cloud. In contrast, a semi-random collisional process will have a stochastic nature in which not all collisions are sudden, there would be a whole range of ways in which dust and debris are stripped from the nucleus: we do not see this. Another argument against their hypothesis is that Comet 12P/Pons-Brooks has exhibited outbursts that share several characteristics with those of 29P. We couldn’t have such a strange collisional process happening in both comets given that 12P is disrupted by relatively close perihelion passages. I should add here that the next paper to be written reporting our 29P findings (hopefully be in conjunction with Slovakian astronomers and others) will analyse those outbursts where we have detailed data covering quiescence, the start and the rise to maximum brightness of each outburst. We now have seven good examples of this. They are:
It is very impressive that MISSION 29P has caught so many given that the rising phase only takes 1-2 hours to unfold and outbursts happen about once every 15 days on average. Richard ? From: [email protected] <[email protected]> On Behalf Of 础苍诲谤é Debackère
Sent: Wednesday, April 24, 2024 9:06 AM To: [email protected] Subject: Re: [29P-ml] New paper: Explanation of the Anomalous Outburst Activity of Comet 29P/Schwassmann–Wachmann 1: The Hypothesis about the Existence of Large Satellites ? Hi Richard and all, If this is indeed the case, contacts are certainly rare, but they must generate a lot of debris, which in turn may come into contact, and so on... Are these satellites or debris detectable, or have they already been detected? All the best 础苍诲谤é Le 23/04/2024 à 22:18, Americo Watkins via groups.io a écrit?:
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Richard Miles
Joan Genebriera