Re: [BAA Comets] A Note on the Phase Law and Light Curve of Comet Tsuchinshan-ATLAS (C/2023 A3) Nick James 19 Jul 2024 07:03 UTC

Morning all,

Over on comets-ml Ignacio Ferrin has posted an email in support of the
imminent demise of this comet:

https://groups.io/g/comets-ml/message/32346

It is worth reading to get an alternative view although he tends to see
fragmentation in many comets where others do not. Ferrin is cited in
Sekanina's papers.

He has used photometry from 4627 observations obtained from the MPC and
claims that this does not show a phase effect. My problem with this
method is that the MPC photometry doesn't use a standardised aperture so
the scatter in the photometry is huge.

He does agree that the images show no sign of "conventional"
fragmentation but proposes that the nucleus is currently disintegrating
due to rapid sublimation and rotation. This seems a rather weak argument
to me. The images show no sign of any kind of trouble with a strong
central condensation and no astrometry bias.

We will see...

Nick.