Re: 29P - First strong outburst of the new observing season
Hello Richard,
Here my observations from this morning 03.16 UT
0029P KC2024 11 03.16014 10 04 50.91 +10 21 30.2 12.6 V A77
0029P KC2024 11 03.16550 10 04 51.10 +10 21 29.5 12.5 V A77
0029P KC2024 11 03.17013 10 04 51.20 +10 21 28.6 12.6 V A77
More Here :
Best regards,
Francois
Le 02/11/2024 ¨¤ 08:55, Richard Miles
via groups.io a ¨¦crit?:
JF Soulier discovered this in the process of brightening
earlier this morning.
Here are our data:
?
NET UCAC-4
0029P ? ? ? ? C2024 11 01.49140 10 04 12.05 +10 26 26.1 ? ? ?
? ?17.09R ? ? ?U94 5.74" (6.15") Lum 180s T11 Manteca
0029P ? ? ? ? C2024 11 01.49375 10 04 12.13 +10 26 26.0 ? ? ?
? ?17.07R ? ? ?U94
?
0029P ? ? ? ?KC2024 11 02.10528 10 04 26.53 +10 24 36.8 ? ?
? ? ?14.38R ? ? ?L27 5.96" (6.70") Clear Soulier
0029P ? ? ? ?KC2024 11 02.12784 10 04 27.04 +10 24 32.9 ? ? ?
? ?13.92R ? ? ?L27
0029P ? ? ? ?KC2024 11 02.15349 10 04 27.64 +10 24 28.2 ? ? ?
? ?13.78R ? ? ?L27
0029P ? ? ? ?KC2024 11 02.17606 10 04 28.17 +10 24 24.1 ? ? ?
? ?13.74R ? ? ?L27
0029P ? ? ? ?KC2024 11 02.20170 10 04 28.75 +10 24 19.6 ? ? ?
? ?13.65R ? ? ?L27
0029P ? ? ? ?KC2024 11 02.21674 10 04 29.10 +10 24 17.1 ? ? ?
? ?13.62R ? ? ?L27
?
0029P ? ? ? ? C2024 11 02.35295 10 04 32.34 +10 23 54.3 ? ?
? ? ?13.42R ? ? ?X07 5.39"(5.57") 60s Rc T72 Miles
0029P ? ? ? ? C2024 11 02.35410 10 04 32.36 +10 23 54.2 ? ? ?
? ?13.40R ? ? ?X07
0029P ? ? ? ? C2024 11 02.35512 10 04 32.36 +10 23 54.0 ? ? ?
? ?13.40R ? ? ?X07
----- end -----
?
Amplitude is 3.6 mag.
?
More observations are strongly encouraged.
Richard
--
Francois KUGEL
Observatoire chante-perdrix
Dauban
04150 BANON - France
MPC station # A77
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29P - First strong outburst of the new observing season
JF Soulier discovered this in the process of brightening earlier this morning.
Here are our data:
?
NET UCAC-4
0029P ? ? ? ? C2024 11 01.49140 10 04 12.05 +10 26 26.1 ? ? ? ? ?17.09R ? ? ?U94 5.74" (6.15") Lum 180s T11 Manteca
0029P ? ? ? ? C2024 11 01.49375 10 04 12.13 +10 26 26.0 ? ? ? ? ?17.07R ? ? ?U94
?
0029P ? ? ? ?KC2024 11 02.10528 10 04 26.53 +10 24 36.8 ? ? ? ? ?14.38R ? ? ?L27 5.96" (6.70") Clear Soulier
0029P ? ? ? ?KC2024 11 02.12784 10 04 27.04 +10 24 32.9 ? ? ? ? ?13.92R ? ? ?L27
0029P ? ? ? ?KC2024 11 02.15349 10 04 27.64 +10 24 28.2 ? ? ? ? ?13.78R ? ? ?L27
0029P ? ? ? ?KC2024 11 02.17606 10 04 28.17 +10 24 24.1 ? ? ? ? ?13.74R ? ? ?L27
0029P ? ? ? ?KC2024 11 02.20170 10 04 28.75 +10 24 19.6 ? ? ? ? ?13.65R ? ? ?L27
0029P ? ? ? ?KC2024 11 02.21674 10 04 29.10 +10 24 17.1 ? ? ? ? ?13.62R ? ? ?L27
?
0029P ? ? ? ? C2024 11 02.35295 10 04 32.34 +10 23 54.3 ? ? ? ? ?13.42R ? ? ?X07 5.39"(5.57") 60s Rc T72 Miles
0029P ? ? ? ? C2024 11 02.35410 10 04 32.36 +10 23 54.2 ? ? ? ? ?13.40R ? ? ?X07
0029P ? ? ? ? C2024 11 02.35512 10 04 32.36 +10 23 54.0 ? ? ? ? ?13.40R ? ? ?X07
----- end -----
?
Amplitude is 3.6 mag.
?
More observations are strongly encouraged.
Richard
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Has 29P entered a new quiescent season last seen 14 years ago?
Thanks everyone who has contributed observations recently.
I have updated two of the 29P .
?
It is now 193 days since we last witnessed a strong outburst!
Admittedly we have had a 74-day gap in data owing to solar conjunction but during the intervening 119 days, we have detected 12 mini-outbursts with amplitudes of <0.8 mag.
That equates to 1 mini-outburst every 10 days on average and NO strong outburst (>1.0 mag amplitude).
?
The last really active period was 2023 August to 2024 January when we recorded EIGHT strong outbursts within 160 days' coverage: SIX took place inside of 54 days!
So it is beginning to look like 29P's unusually quiescent season from one orbit of the Sun earlier is starting to repeat itself.
That relatively inactive time started after a particularly active set of strong outbursts that happened between 2009 October and 2010 April, which was some 14 years and 2 months prior to this recent set, i.e. close to 29P's orbital period of about 14.7 years.
?
Expect the occasional few strong outbursts over the next 4 years but the big question is, "Will they all appear from one hemisphere of the nucleus like last time?", when we observed at least 16 such 'lopsided' events?
?
Richard
?
Here's the latest current lightcurve fyi:
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Re: 29P: Two new mini-outbursts in quick succession> Alert for follow-up
On Sun, Oct 27, 2024 at 02:20 AM, Richard Miles wrote:
?
Richard,
?
Yes still the same, 0.25-m telescope, 4 pixels radius and 1.36 "/pixel.
?
Kevin.
?
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Latest 29P lightcurve showing the October 20 and October 22 mini-outbursts
Observations through to October 26:
29P is becoming more observable now that its solar elongation has passed 65¡ã and the Moon is parting company with the comet.
The first 6 weeks coverage of a new apparition is always difficult but we probably have obtained are best data yet for the early part of the observing window having recorded 4 mini-outbursts to date.
?
This object is very different to a 'normal' comet in that by far the majority of dust is ejected from the nucleus by way of sudden and discrete cryovolcanic eruptions. The first 3 outbursts from this year's coverage have already shown how mini-outbursts continue to feed the coma even though the casual observer would consider the comet to be essentially quiescent. However, we also know that there exists an underlying outgassing from the nucleus and this has been well shown by last year's James Webb Space Telescope observations of CO and CO2 continuing to escape. Although a large fraction of the surface crust blocks gas escaping, some regions remain relatively porous.
?
Clear skies,
Richard
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Re: 29P: Two new mini-outbursts in quick succession> Alert for follow-up
Kevin,
?
That is really helpful having your observations from early today.
We often have gaps in our coverage when 29P is close to the Moon in the sky.
I'll incorporate your observations and send out an up-to-date lightcurve.
?
One question though - Can you confirm the radius of your measuring aperture in pixels and also the image scale on the sky in arcseconds per pixel?
The default for your 0.25-m telescope that I have is 4 pixels radius and 1.36 "/pixel.
?
Clear skies,
Richard
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Re: 29P: Two new mini-outbursts in quick succession> Alert for follow-up
Observation update: This morning, the moon was at 24% illumination and positioned 8¡ã from 29P. Captured data includes two stacks of 90-second subs.
---------------------------------------------------------------
? ? ? JD ? ? ? ? mag ? ? Flt ? SNR ? ?ZeroPt ? ? ?Cat ? Design.
---------------------------------------------------------------
2460610.69300 ? 16.909 R ?C ? 39.71 ? 25.843 ? ?UCAC4 ? 29P/Schwassmann-Wachmann
2460610.71009 ? 16.982 R ?C ? 42.98 ? 25.972 ? ?UCAC4 ? 29P/Schwassmann-Wachmann
---- end -----
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! astrometry Astrometrica 4.15.0.455
! photometry Astrometrica 4.15.0.455
permID |provID ? ? |trkSub ?|mode|stn |obsTime ? ? ? ? ? ? ? ?|ra ? ? ? ? |dec ? ? ? ?|rmsRA|rmsDec|astCat ?|mag ?|rmsMag|band|photCat |photAp|logSNR|seeing|exp |rmsFit|nStars|notes|remarks
? ? 29P| ? ? ? ? ? | ? ? ? ?| CCD|M64 |2024-10-27T04:37:56Z ? |150.49973 ?|+10.71170 ?|0.34 |0.40 ?| ? UCAC4|16.9 |0.15 ?| ? R| ? UCAC4| 4.8 ?|1.60 ?|3.4 ? |1350|0.49 ?| ? 105|K ? ?|
? ? 29P| ? ? ? ? ? | ? ? ? ?| CCD|M64 |2024-10-27T05:02:32Z ? |150.50115 ?|+10.71066 ?|0.29 |0.40 ?| ? UCAC4|17.0 |0.16 ?| ? R| ? UCAC4| 4.8 ?|1.63 ?|3.4 ? |1350|0.46 ?| ? 113|K ? ?|
?
Kevin J.
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Re: 29P: Two new mini-outbursts in quick succession> Alert for follow-up
Here's what the follow-up photometry looks like:
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0029P ? ? ? ?KC2024 10 23.44995 10 00 19.17 +10 54 43.2 ? ? ? ? ?16.35R ? ? ?U94 5.74" (6.15") 3x60s Lum T11 Herman
0029P ? ? ? ? C2024 10 24.11583 10 00 37.51 +10 52 35.0 ? ? ? ? ?16.44R ? ? ?L09 5.18" (5.55") r 180s Miles
0029P ? ? ? ?KC2024 10 24.16618 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?16.40R ? ? ?M64 5.44" (6.12") 12x90s Lum Johnson
0029P ? ? ? ?KC2024 10 24.18581 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?16.45R ? ? ?M64
0029P ? ? ? ?KC2024 10 24.20543 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?16.46R ? ? ?M64
0029P ? ? ? ? C2024 10 24.46382 10 00 47.03 +10 51 26.0 ? ? ? ? ?16.44R ? ? ?U94 5.74" (6.15") 180s Lum T11 Manteca
0029P ? ? ? ? C2024 10 24.46616 10 00 47.12 +10 51 25.2 ? ? ? ? ?16.45R ? ? ?U94
0029P ? ? ? ? C2024 10 24.57714 10 00 50.12 +10 51 03.9 ? ? ? ? ?16.54R ? ? ?T03 5.18" (5.55") r 180s Miles
----- end -----
Thanks Pep¨¦, Kevin and Eliot for your contributions, which give an idea of the good accuracy observers are obtaining even though the 'comet' is faint at 16th magnitude.
It is also reassuring to know that the 29P-ml group can respond effectively even when the observations requested are in the early hours of the morning.
?
Thanks all,
Richard
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Re: 29P: Two new mini-outbursts in quick succession> Alert for follow-up
Peter - Let's correspond offline to get you up to speed. I will need to have some of your FITS files (flat, dark and stack of 3 frames say).
Pep¨¦ Manteca and Kevin Johnson also obtained images, etc. so it will be a good opportunity to check your observations against others.
?
Thanks for observing,
Richard
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Re: 29P: Two new mini-outbursts in quick succession> Alert for follow-up
Richard,
Results of my observation of 29p earlier this morning (24th).
3 stacks of 12x90s subs.
Aperture 5.44¡±
OBSERVER: ? ?K Johnson
OBS CODE: ? ?M64
TELESCOPE: ? 0.25m f/7.0 Meade SCT
EXPOSURE JD: Mid-exposure, not corrected for light time
---------------------------------------------------------------
? ? ? JD ? ? ? ? mag ? ? Flt ? SNR ? ?ZeroPt ? ? ?Cat ? Design.
---------------------------------------------------------------
2460607.66618 ? 16.398 R ?C ? 66.03 ? 26.029 ? ?UCAC4 ? 29P/Schwassmann-Wachmann
2460607.68581 ? 16.447 R ?C ? 65.61 ? 26.111 ? ?UCAC4 ? 29P/Schwassmann-Wachmann
2460607.70543 ? 16.460 R ?C ? 68.08 ? 26.111 ? ?UCAC4 ? 29P/Schwassmann-Wachmann
----- end -----
Kevin J.
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Re: 29P: Two new mini-outbursts in quick succession> Alert for follow-up
Hello Richard
I managed 45 x 60 second images unguided between 03:35 UT and 04:19 UT using an ASI432MM and 0.68 reducer with my 14inch f/10 SCT.?? I also took flats but have temporarily forgotten how to incorporate them in Astrometrica.? Without the flats I have grouped together the images in threes = 180 seconds per image.? Two sets have failed to read properly due to passing satellite trails but the first four sets that do read are between mag 16.3 and mag 16.4.?? I will try to work further on the data to send a photometric report but if I could be reminded how I combine sets with the flats I'd be grateful.
Regards,
Peter T
On Wed, 23 Oct 2024 at 21:08, Richard Miles via <rmiles.btee= [email protected]> wrote: If you can observe and image 29P tonight, we would like photometry confirmation of the significant outburst that appears to have taken place about 24 hours ago.
Please post to the Group if you are successful.
Clear skies,
Richard
?
P.S. Here are all the recent data showing the two sudden eruptions of the nucleus:
?
UCAC4
0029P ? ? ? ? C2024 10 19.63590 09 58 30.63 +11 07 20.2 ? ? ? ? ?17.30R ? ? ?F65 5.61" (5.72") r 90s Malaric
0029P ? ? ? ? C2024 10 19.63702 09 58 30.55 +11 07 20.6 ? ? ? ? ?17.26R ? ? ?F65
0029P ? ? ? ? C2024 10 19.63813 09 58 30.60 +11 07 19.8 ? ? ? ? ?17.29R ? ? ?F65
Mini-outburst at 2024 10 20.11¡À0.37 ?17.30 => 16.97 (Intensity = 0.78 nucleus-equivalents)
0029P ? ? ? ? C2024 10 20.58462 09 58 58.12 +11 04 12.6 ? ? ? ? ?16.94R ? ? ?T03 5.18" (5.55") r 180s Miles
0029P ? ? ? ?KC2024 10 21.12994 09 59 13.77 +11 02 23.1 ? ? ? ? ?16.88R ? ? ?L27 5.96" (6.70") Clear Soulier
0029P ? ? ? ?KC2024 10 21.14123 09 59 14.09 +11 02 20.7 ? ? ? ? ?16.96R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.15252 09 59 14.40 +11 02 18.5 ? ? ? ? ?16.94R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.16580 09 59 14.79 +11 02 15.8 ? ? ? ? ?16.91R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.17824 09 59 15.14 +11 02 13.4 ? ? ? ? ?16.96R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.18953 09 59 15.46 +11 02 11.2 ? ? ? ? ?16.97R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.20099 09 59 15.79 +11 02 08.9 ? ? ? ? ?16.98R ? ? ?L27
0029P ? ? ? ? C2024 10 21.58460 09 59 26.77 +11 00 52.7 ? ? ? ? ?17.03R ? ? ?T03 5.18" (5.55") r 180s Miles
0029P ? ? ? ? C2024 10 22.58458 09 59 55.05 +10 57 34.4 ? ? ? ? ?17.09R ? ? ?T04 5.18" (5.55") r 180s Miles
Mini-outburst at 2024 10 22.82¡À0.19 ?17.10 => 16.35 (Intensity = 2.6 nucleus-equivalents)
0029P ? ? ? ?KC2024 10 23.07249 10 00 08.68 +10 55 57.2 ? ? ? ? ?16.29R ? ? ?C10 6.48¡å (7.29¡å) Clear Soulier
0029P ? ? ? ?KC2024 10 23.08540 10 00 09.04 +10 55 54.7 ? ? ? ? ?16.22R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.09882 10 00 09.38 +10 55 52.3 ? ? ? ? ?16.35R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.11257 10 00 09.77 +10 55 49.7 ? ? ? ? ?16.30R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.12987 10 00 10.24 +10 55 46.3 ? ? ? ? ?16.26R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.14356 10 00 10.62 +10 55 43.6 ? ? ? ? ?16.30R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.15595 10 00 10.97 +10 55 41.1 ? ? ? ? ?16.30R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.16833 10 00 11.31 +10 55 38.7 ? ? ? ? ?16.24R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.18355 10 00 11.72 +10 55 35.8 ? ? ? ? ?16.29R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.19664 10 00 12.10 +10 55 33.3 ? ? ? ? ?16.33R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.21315 10 00 12.54 +10 55 30.3 ? ? ? ? ?16.30R ? ? ?C10
----- end -----
?
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29P: Two new mini-outbursts in quick succession> Alert for follow-up
If you can observe and image 29P tonight, we would like photometry confirmation of the significant outburst that appears to have taken place about 24 hours ago.
Please post to the Group if you are successful.
Clear skies,
Richard
?
P.S. Here are all the recent data showing the two sudden eruptions of the nucleus:
?
UCAC4
0029P ? ? ? ? C2024 10 19.63590 09 58 30.63 +11 07 20.2 ? ? ? ? ?17.30R ? ? ?F65 5.61" (5.72") r 90s Malaric
0029P ? ? ? ? C2024 10 19.63702 09 58 30.55 +11 07 20.6 ? ? ? ? ?17.26R ? ? ?F65
0029P ? ? ? ? C2024 10 19.63813 09 58 30.60 +11 07 19.8 ? ? ? ? ?17.29R ? ? ?F65
Mini-outburst at 2024 10 20.11¡À0.37 ?17.30 => 16.97 (Intensity = 0.78 nucleus-equivalents)
0029P ? ? ? ? C2024 10 20.58462 09 58 58.12 +11 04 12.6 ? ? ? ? ?16.94R ? ? ?T03 5.18" (5.55") r 180s Miles
0029P ? ? ? ?KC2024 10 21.12994 09 59 13.77 +11 02 23.1 ? ? ? ? ?16.88R ? ? ?L27 5.96" (6.70") Clear Soulier
0029P ? ? ? ?KC2024 10 21.14123 09 59 14.09 +11 02 20.7 ? ? ? ? ?16.96R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.15252 09 59 14.40 +11 02 18.5 ? ? ? ? ?16.94R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.16580 09 59 14.79 +11 02 15.8 ? ? ? ? ?16.91R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.17824 09 59 15.14 +11 02 13.4 ? ? ? ? ?16.96R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.18953 09 59 15.46 +11 02 11.2 ? ? ? ? ?16.97R ? ? ?L27
0029P ? ? ? ?KC2024 10 21.20099 09 59 15.79 +11 02 08.9 ? ? ? ? ?16.98R ? ? ?L27
0029P ? ? ? ? C2024 10 21.58460 09 59 26.77 +11 00 52.7 ? ? ? ? ?17.03R ? ? ?T03 5.18" (5.55") r 180s Miles
0029P ? ? ? ? C2024 10 22.58458 09 59 55.05 +10 57 34.4 ? ? ? ? ?17.09R ? ? ?T04 5.18" (5.55") r 180s Miles
Mini-outburst at 2024 10 22.82¡À0.19 ?17.10 => 16.35 (Intensity = 2.6 nucleus-equivalents)
0029P ? ? ? ?KC2024 10 23.07249 10 00 08.68 +10 55 57.2 ? ? ? ? ?16.29R ? ? ?C10 6.48¡å (7.29¡å) Clear Soulier
0029P ? ? ? ?KC2024 10 23.08540 10 00 09.04 +10 55 54.7 ? ? ? ? ?16.22R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.09882 10 00 09.38 +10 55 52.3 ? ? ? ? ?16.35R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.11257 10 00 09.77 +10 55 49.7 ? ? ? ? ?16.30R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.12987 10 00 10.24 +10 55 46.3 ? ? ? ? ?16.26R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.14356 10 00 10.62 +10 55 43.6 ? ? ? ? ?16.30R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.15595 10 00 10.97 +10 55 41.1 ? ? ? ? ?16.30R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.16833 10 00 11.31 +10 55 38.7 ? ? ? ? ?16.24R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.18355 10 00 11.72 +10 55 35.8 ? ? ? ? ?16.29R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.19664 10 00 12.10 +10 55 33.3 ? ? ? ? ?16.33R ? ? ?C10
0029P ? ? ? ?KC2024 10 23.21315 10 00 12.54 +10 55 30.3 ? ? ? ? ?16.30R ? ? ?C10
----- end -----
?
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Re: Two possible mini-outbursts of 29P buried in our data
Here's the updated plot, three mini-outbursts of amplitude 0.30 mag, 0.20 mag and 0.33 mag.
?
This plot is a good example of why working together on this observing campaign allows us to see eruptions that would otherwise be missed.?
That's because at 17th magnitude the scatter of the individual data points is around 0.10- 0.15 mag.
Having five or six observations every 2-3 days enables us to recognise mini-outbursts with high certainty despite being almost another 4 months before 29P reaches opposition.
?
Richard
?
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Two possible mini-outbursts of 29P buried in our data
Dear All,
?
Here's an expanded plot of the 58 observing epochs so far this season.
Buried amongst the datapoints are two mini-outbursts of about 0.30 mag and 0.20 mag amplitude.
?
Do people agree?
?
Richard
|
2024 - 2025 lightcurve of 29P / JWST observations
The observing season is properly commencing for observers now that the comet is approaching 60¡ã solar elongation and so it is becoming properly accessible in the morning sky.
We have had good coverage over nearly 40 Earth-days so far and there is no really significant outburst as yet. The last time an apparition was so quiet from the outset was in 2013!
Here's the lightcurve taken from the :
?
?
Despite the nucleus being quiescent, it is clear from last year's James Webb Space Telescope observations (on 2023 Feb 20) that a quiescent coma is maintained thanks mainly to significant outgassing of CO, which was largely from the northern hemisphere of the nucleus at that time. This finding confirms our own observations that suggest the coma stabilises (when no outburst has happened for 20-40 days) such that the projected area of dust in the quiescent coma (5.7" radius) is almost the same as the area of the bare nucleus. Our data in the past also shows that an outburst becomes highly likely when the reduced magnitude drops below R(1,1,0) > 9.00. That condition appears to be approaching. as I write.
?
Interestingly, I have been able to analyse the JWST data recently measuring the coma profile and the brightness of the nucleus in several hundred different parts of the spectrum ranging from 0.60 microns to 5.30 microns. It is good that JWST coverage starts at 0,60 microns because the first 7 slices from 0.600 to 0.635 cover the central region of the SDSS-r filter. That means we can do comparisons between MISSION 29P observations such as the coma profile before and just hours after the JWST epoch. We also witnessed a strong outburst about 30 hours after the JWST coverage and so we know which part of the nucleus it emanated from. It turns out that it was from a region that showed little if any outgassing of CO suggesting that the pressure beneath the crust was slowly accumulating without any effective 'safety valve' to leak CO gas. Hence the rupture in the crust and the ejection within 10 minutes or so of almost 20 times as much coma material as JWST measured one day earlier. Dramatic!
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I am planning to publish an extra MISSION 29P webpage in which I shall report the comparisons between our observations and JWST. But also, I have been studying the entire set of spectral slices, which comprise about 940 in all, so there are one two other interesting features I would like to draw your attention to.
?
More images and photometry would be much welcomed over the coming days as we may very well see another outburst within the next week or two.
?
Richard
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First 29P outburst of the 2024-25 observing season looks to have taken place earlier today (October 01)
We look to have had the first outburst of the new apparition. It is a mini-outburst of 0.5 mag amplitude on 2024 October 01. It was evident from photometry by Denis Buczynski and Richard Miles, this event is quite weak amounting to only 1.5 nucleus-equivalents in intensity. Detection was only possible thanks to 29P having faded to a quiescence level that was last seen on 2023 Dec 08 just before it exhibited a strong outburst on that date. The latter part of the previous 2023?2024 apparition saw an enhanced level of activity around quiescence: a consequence of lots of repeated mini-outbursts.
?
Final confirmation of this outburst will have to wait for 1.0-m and/or 2.0-m images tomorrow (Oct 2).
?
The forthcoming season will be particularly interesting as I first began observing 29P using the Faulkes telescopes on 02 February 2010 when it had just outburst by chance. Those observations were the basis for a paper that was published in Icarus in 2016. Currently it is 14.66 years since that initial observation and the orbital period of 29P is 14.87 years. So we are about to reach a full revolution of the Sun. What was particularly interesting was that after that 2010 outburst virtually all strong outbursts that happened over the next 3-4 years all came from one side of the nucleus subtending <150¡ã in longitude. Whether we see a similar behaviour of the comet as it starts a new orbit of the Sun, we shall see. If the strong outbursts do come from one side of the nucleus, it will give us a second opportunity to derive its rotation period as the current 57.7-day period was evident in part from the 2010?2014 observations.
?
See for reported photometry.?
?
Richard
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Call to observe 29P ... ...
Just to say that observers are strongly encouraged to start contributing observations of 29P now that this bizarre object is about to exceed 35¡ã solar elongation and so should be easily visible low down in the morning sky before dawn.
The next few weeks are a good time to resume coverage of this object as even when it appears to pass close to the Moon on September 29, the Moon will just be a thin waning crescent and so moonlight should not interfere.
?
Thanks to the work of our indefatigable observer, Jean-Fran?ois Soulier observing from home in northern France we know that the 'comet' has been essentially quiescent over the last 12 days as can be seen from his results listed below.
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Best of luck for clear skies,
Richard?
?
NET UCAC-4
0029P ? ? ? ?KC2024 09 08.15563 09 33 46.62 +13 42 35.6 ? ? ? ? ?16.37R ? ? ?C10 6.48¡å (7.29¡å) Clear 40x20s Elong.=24.4¡ã Soulier
0029P ? ? ? ?KC2024 09 08.15876 09 33 46.78 +13 42 33.6 ? ? ? ? ?16.30R ? ? ?C10
0029P ? ? ? ?KC2024 09 08.16188 09 33 46.79 +13 42 33.6 ? ? ? ? ?16.57R ? ? ?C10
0029P ? ? ? ?KC2024 09 13.15029 09 37 08.09 +13 22 56.1 ? ? ? ? ?16.17R ? ? ?C10 6.48¡å (7.29¡å) Clear 40x20s Elong.=28.3¡ã Soulier
0029P ? ? ? ?KC2024 09 13.15681 09 37 08.45 +13 22 53.2 ? ? ? ? ?15.96R ? ? ?C10
0029P ? ? ? ?KC2024 09 13.16334 09 37 08.64 +13 22 52.1 ? ? ? ? ?16.36R ? ? ?C10
0029P ? ? ? ?KC2024 09 15.14108 09 38 27.20 +13 15 07.2 ? ? ? ? ?16.51R ? ? ?C10 6.48¡å (7.29¡å) Clear Elong.=29.9¡ã Soulier
0029P ? ? ? ?KC2024 09 15.14889 09 38 27.53 +13 15 04.2 ? ? ? ? ?16.48R ? ? ?C10
0029P ? ? ? ?KC2024 09 15.17734 09 38 28.62 +13 15 00.0 ? ? ? ? ?16.51R ? ? ?C10
0029P ? ? ? ?KC2024 09 18.15146 09 40 25.07 +13 03 21.7 ? ? ? ? ?16.56R ? ? ?C10 6.48¡å (7.29¡å) Clear Elong.=32.4¡ã Moon 100% Soulier
0029P ? ? ? ?KC2024 09 18.15927 09 40 25.40 +13 03 19.5 ? ? ? ? ?16.16R ? ? ?C10
0029P ? ? ? ?KC2024 09 18.16708 09 40 25.63 +13 03 18.7 ? ? ? ? ?16.85R ? ? ?C10
0029P ? ? ? ?KC2024 09 19.15144 09 41 03.98 +12 59 27.0 ? ? ? ? ?16.73R ? ? ?C10 6.48¡å (7.29¡å) Clear Elong.=33.2¡ã Soulier
0029P ? ? ? ?KC2024 09 19.16083 09 41 04.19 +12 59 26.2 ? ? ? ? ?16.96R ? ? ?C10
0029P ? ? ? ?KC2024 09 19.17022 09 41 04.58 +12 59 23.6 ? ? ? ? ?16.58R ? ? ?C10
0029P ? ? ? ?KC2024 09 20.14962 09 41 42.24 +12 55 35.6 ? ? ? ? ?16.48R ? ? ?C10 6.48¡å (7.29¡å) Clear Elong.=34.0¡ã Soulier
0029P ? ? ? ?KC2024 09 20.16212 09 41 42.70 +12 55 33.4 ? ? ? ? ?16.64R ? ? ?C10
0029P ? ? ? ?KC2024 09 20.17149 09 41 43.07 +12 55 31.0 ? ? ? ? ?16.73R ? ? ?C10
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2024-25 Observers' List:
C10 J.-F. Soulier ? ?Maisoncelles Observatory, France TEL 0.30-m f/3.8 Newtonian, ? ? ? ? ? ? ?no filter, ? ?6.48" (4pix)
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Start of the 2024-25 observing campaign
Jean-Fran?ois Soulier obtained the following impressive image on 2024 September 08 showing the comet to be largely quiescent at the moment.
The image was taken at an altitude of 7¡ã above the horizon and a solar elongation of 24.4¡ã.
The gap in observations owing to solar conjunction has been 74.0 days, which compares favourably with the average for the last TEN 29P apparitions of 70.8 days.
The effective photometric aperture of Jean-Fran?ois¡¯ measurement was 7.3¡å (radius) and so the measured mean value of 16.41R translates to a standard magnitude of about16.8R in a 5.7¡å radius aperture. The cometwas 6.229 au from the Sun at the time and 7.133 au from Earth (3.8¡ã phase angle), which is equivalent to an absolute R(1,1,0) mag of 8.5. It may therefore fade by up to a further 0.5 mag before we see the next outburst.
On the other hand, an outburst may happen tomorrow!
More observations are strongly encouraged.
Richard
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Re: Tea break over....back to work!
Yes indeed, Matt.
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Jean-Fran?ois tried imaging 29P a couple of days ago but could only reach a limiting magnitude of 10.
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Currently the 'comet' is approaching 20¡ã solar elongation (on September 3) so anytime after that date would be when to start picking it up again after solar conjunction.
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Clear skies,
Richard
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Tea break over....back to work!
I wish you all clear skies and serene early mornings for the coming 29P season.
Roeser Observatory
Luxembourg
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Richard Miles