9 replies to this topic

[Thomas Ashcraft]

Nov 20 2020 0317 UT. Single 100 second exposure.

 

Here is Comet 29P Schwassmann-Wachmann in outburst. I was expecting something more dramatic like a nice lop-sided coma that I have seen in 29P months and years ago. I had to wait to see movement to confirm. It looked like just another star.

 

Canon 6D, C14, Backyard EOS, New Mexico

Attached Thumbnails

• 

[MikeTahtib]

What does it mean for a comet to be "in outburst"?

Also, is that a galaxy to the left of the comet?  It looks like there might be a lot of galaxies in the picture.

[Thomas Ashcraft]

29P timelapse  Nov 20, 2020.  0321 Through 0441 UT

Attached Thumbnails

• 

[Thomas Ashcraft]

What does it mean for a comet to be "in outburst"?

Also, is that a galaxy to the left of the comet?  It looks like there might be a lot of galaxies in the picture.

https://www.scienced...019103515005217

 

Quoting from the paper listed above particularly for this comet 29P:  "An outburst occurs when insolation heating of the crust above a gas-laden subsurface reservoir softens paraffinic hydrocarbons and causes a crustal plate to dislodge under the accumulated gas pressure, the sudden release of which provokes the explosive ex-solution of dissolved gases, principally CO, propelling entrained dust and debris into space."

 

Yes, there are a few galaxies in the pic. Always happy to see that.

[BrooksObs]

What does it mean for a comet to be "in outburst"?

Also, is that a galaxy to the left of the comet?  It looks like there might be a lot of galaxies in the picture.

From an observational standpoint the initial phase of a cometary "outburst" is revealed by the appearance of a new bright star-like nucleus at the heart of the comet's coma accompanied by a distinct rise in the comet's apparent total brightness/magnitude (largely just the result of the newly formed bright nucleus). In subsequent days the star-like nucleus becomes increasing more diffuse in appearance, transitioning into a small fairly sharp disk-like feature which expands day by day until it diffuses away. In the end the comet may, or may not, retain its newly increased brightness, awaiting the next outburst, if any.

 

Brightenings of 29P always start out with the star-like phase as illustrated in the OP's image. In days the comet, due to the rotation of the nucleus, or perhaps our viewing angle of it, either the disk phase will evolve, or take on the appearance of a one-armed spiral galaxy. I would add that outbursts of 29P are typically among the largest displayed by any comet, often amounting to 8 to 10 magnitudes!

 

I believe that I was the first to call attention to the fact that outbursts of 29P were far more common than long believed (thought to be only once or twice a year, according to Dr. E. Roemer, USNO) when I began observing outbursts coming at the rate of nearly one a month back in the 1970's or early 80's. Since that time the comet has been frequently observed in outburst via monitoring by other advanced amateur astronomers.

 

BrooksObs

Edited by BrooksObs, 21 November 2020 - 11:04 AM.

[Thomas Ashcraft]

From my archives:  Here is a picture I took of Comet 29P/Schwassmann-Wachmann exhibiting a jet on Oct 04 2018  0223 UT through 0305 UT. Stacked in Nebulosity, 36 x 60 second exposures, 16000 ISO, C14, Canon 6D, BYEOS.

Attached Thumbnails

• 

[Sheol]

          Now this last pic is very similar to my view of Comet Halley back in November/December of 1985 in the Observatory at LSU. This really brings back the nostalgia for me. 

 

       Clear Skies,

          Matt.

       PS.

       I do not remember the exact diameter of that 'Scope only that it was a large refractor. They offered us a free viewing if interested that year. Of course, I took it. Some of my friends also.. Good thing, better sight than we got later.

[Thomas Ashcraft]

UPDATE: 29P showing shape now

 

Comet 29P Schwassmann-Wachmann in Outburst
November 22, 2020  0155 UT
Single 60 second exposure,     
Thomas Ashcraft, New Mexico

Attached Thumbnails

• 

[SNH]

Oh, thank you so much Thomas for this report!!! I've always wanted to see 29P Schwassmann-Wachmann, but never know when it will be in "outburst". Plus, as a star-hopper, making maps to find it aren't easy considering how faint it usually is.

 

Over on the Comet ATLAS thread, Dave Mitsky kindly gave a link to the awesome Comet OBServation database, which allowed me get a feel for how faint 29P might be. So this morning, armed with my 130mm reflector and a map from TheSkyLive, I tried for it. Used 108x to spot it, then could see it with 59x, then even with 34x. Did a magnitude estimate and got right at about +13.0 thanks to the +13.1 star close by. It had a bright little nucleus and a small softness around it - pretty much like the image posted above.

 

So, again, thank you for giving this report! I couldn't have see it without you!

Scott

[Thomas Ashcraft]

I've always wanted to see 29P Schwassmann-Wachmann, but never know when it will be in "outburst".

That's great. It is a neat comet for sure.  Maybe it will make a jet. Clear skies to you, Thomas