Comet 12P/Pons-Brooks (aka the "Millenium Falcon" Comet) Flares Again!

By: Bob King October 6, 2023 4

Comet 12P/Pons-Brooks has awakened again from its recent slumbers with a fresh outburst. It’s now bright enough to see in a modest telescope.

Comet 12P/Pons-Brooks outburst — Taken on October 5th, this photo matches the comet's visual appearance with a strongly-condensed inner coma surrounded by a somewhat larger and considerably fainter outer coma. A faint tail trails off to the northeast.
*Eliot Herman*

Periodic Comet 12P/Pons-Brooks remains in character as it heads toward perihelion next April. Famous for its unpredictable outbursts during previous appearances, it blew up again around October 5.2 UT, waxing nearly 100 times brighter (nearly 5 magnitudes!) compared to the night prior. Had you sought the comet on October 3rd, you might have looked in vain for a diffuse 14.5-magnitude object. By late the next evening, it had catapulted to magnitude 11.0 with a nearly stellar appearance, surrounded by a tiny, dense coma just half an arcminute across.

12P/Pons-Brooks map — Lucky for us, Comet 12P/Pons-Brooks happens to pass between the 4th-magnitude star Iota Herculis and the bright globular cluster M92 in Hercules, making it straightforward to find. The map plots stars to magnitude 13 with north up. There are no deep sky objects brighter than 13th magnitude along the comet's path, shown nightly from Oct. 7 through Nov. 1.
*MegaStar, courtesy of Emil Bonanno*

I hauled out my 15-inch between rain showers on Thursday night (Oct. 5th) and, using 64×, spotted the bright but slightly fuzzy nub at magnitude 11.3, with a degree of condensation of 8. I suspected a faint, short tail pointing east, as shown in the images.

Now, it's within reach of smaller scopes. The coma will expand, and the comet will gradually fade over time, but for now it's within grasp of a 6-inch telescope from dark skies. The scarce visitor — it only drops by every 71 years —is currently crossing northern Hercules, not far from the bright globular cluster M92.

Bonus! The Moon stays out of the way until around October 21st.

Comet 12P/Pons-Brooks outburst July 2023 — The comet's expanding coma on July 26th mimicked the appearance of the Star Wars Millennium Falcon. Early indications are it's evolving into a similar shape during the current outburst.
*Gianluca Masi*

This is the fourth recorded outburst for 12P/Pons-Brooks this apparition. The first occurred on July 20th and was similarly bright. In the aftermath its coma expanded to resemble a horseshoe crab or, more fancifully, the Millennium Falcon from Star Wars. Two fainter flares followed on September 4th and 23rd, with respective magnitude increases of approximately 0.5 and 0.9.

The bursts are believed to originate from the outgassing of carbon monoxide and dioxide in the comet's core, which escape when solar heating weakens and fractures the overlying crust. The explosive eruption releases up to a million tons of dust, ice, and other detritus. Illuminated by sunlight the expanding cloud of debris swiftly ratchets up the comet's brightness.

Comet 12P/Pons-Brooks Oct. outburst — The Millennium Falcon flies again! The comet is again developing its trademark outburst coma as seen in this Oct. 6th image.
*Comet Chasers (Helen Usher) with the Faulkes Telescope North via LCO*

Jose Manuel Pérez Redondo (Institut d’Alcarras, Spain) and Ben Wooding's students (St Mary's Primary School, Bridgend) discovered this second strong outburst in images made with the Faulkes Telescope North 2-meter telescope in Haleakala in Maui, Hawai'i. They and other members of the Comet Chasers education and outreach project and the LCO Outbursting Objects Key (LOOK) Project have been regularly monitoring the comet. You can read more discovery details in The Astronomers Telegram and an analysis of its current appearance by Richard Miles (British Astronomical Association) on the Comet 12P Observations site.

12P/Pons-Brooks detail — A stack of six images made with the 2.0-meter Faulkes Telescope North reveals new details in the comet's expanding coma. "The image was taken about 25 hours after the 11th magnitude outburst that took place on 2023 October 05.16 ± 0.03," said Richard Miles. "There is much fine detail visible in the remarkable fast-moving outflows that exhibit two-axis symmetry, together with what looks like two circularly symmetric coma, one concentric within the other."
*Courtesy Richard Miles*

I hope you get a chance to see this fitful visitor, one of the best examples of what makes comets so much fun to watch.

Comments

OwlEye

October 7, 2023 at 11:40 am

Hi Bob,

As we had hoped, 12P did it again!

I did not have a chance see your article until just this morning, but after seeing photos by Yaeger and Ruppel on Spaceweather.com yesterday, I decided to give it a go last night with the 6-inch f/8 reflector, since the comet's size appeared to be less than 1 arcminute.

Starting at 30 X, I could see nothing, but upping the magnification to 94 X with a 13 mm eyepiece made it quite easy to see . . . with averted vision. Direct vision showed nothing.

I was quite pleased with this observation, considering the faint Bishop's Ring visible before sunset, betraying the presence of smoke in the upper air, and the limits of my Bortle 6.5 skies.

After a long, careful look, I was able determine 12P's angular size was close to the separation of two particular stars in the field of view measuring ~ 42 arcseconds, while a nearby star thrown out of focus to the comet's apparent size and compared to the comet in focus gave an ~ magnitude of 11.6.

Hopefully, we will have at least a trifecta of outbursts before 12P arrives at perihelion next April 21st ! !

Regards,
DZ

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Bob KingPost Author

October 7, 2023 at 4:38 pm

Hi Doug,

You did well with that 6-inch! Observers with similar sized instruments will hopefully read how you ultimately pulled in the comet and use it as a template to finding it themselves. I also observed it at about the same time and derived a similar size and magnitude using my 15-inch. I'm up for any and all trifectas involving astronomical phenomena! Quadfectas also acceptable 🙂

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OwlEye

October 7, 2023 at 12:29 pm

Whoops, I did not mean trifecta, but quadfecta (quadfecta?).

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OwlEye

October 8, 2023 at 11:53 am

Hi Bob,

We had a much clearer and therefore darker sky last night, and again using the 6-inch at 94 X, I had a look at 12P.

It was nearly undetectable, and only very long, steady observations using averted vision would show it. The brightest part of the coma appeared to have at least doubled in size in the last 24 hours. Too difficult to see to measure, or estimate magnitude (though I imagine the magnitude had not changed much).

If it remains clear tonight, my only chance in my skies would be to use the 12.5-inch.

Regards,
DZ

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