Jeremy,

This is an interesting paper definitely worth a read. 108P is an odd
object and this leads to it regularly being the subject of
disintegration reports. There are lots of images of it in our archive:

https://britastro.org/cometobs/108p/index.html

and it was the subject of quite a bit of speculation at its last return
in the winter of 21/22.

The paper contains an HST image taken on 2022 Feb 5. It is interesting
to compare it with the amateur images taken at the same time.

Nick.

On 13/02/2023 13:39, Jeremy Shears wrote:
>
> 
> AJ preprint: https://arxiv.org/abs/2302.03697<https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Farxiv.org%2Fabs%2F2302.03697&data=05%7C01%7C%7C9dc5ee68b7124e9787fc08db0d88555d%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638118651416299934%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=yU20WOmQDlLPtePDuuegBwA2H%2F4u%2FtlIFJGHkRDqYEs%3D&reserved=0>
>
> Comet 108P/Ciffreo: The Blob
>
> Yoonyoung Kim, David Jewitt, Jane Luu, Jing Li, Max Mutchler
>
> Short-period comet 108P/Ciffreo is known for its peculiar double morphology, in which the nucleus is accompanied by a co-moving, detached, diffuse 'blob'. We report new observations of 108P/Ciffreo taken with the Hubble Space Telescope and the Nordic Optical Telescope and use them to determine the cause of this unusual morphology. The separation and the longevity of the blob across several orbits together rule out the possibility of a single, slow-moving secondary object near the primary nucleus. We use a model of coma particle dynamics under the action of solar gravity and radiation pressure to show that the blob is an artifact of the turn-around of particles ejected sunward and repelled by sunlight. Numerical experiments limit the range of directions which can reproduce the morphology and explain why the co-moving blob appearance is rare.
>
> To unsubscribe from this list please go to https://archives.simplelists.com/confirm/?u=Aj4vCBHI6JSRpYRB2DWvMTYlWL2vuAnC
>