Cometary Science Newsletter

December 2020
Michael S. P. Kelley (

P/2019 LD2 Observing Campaign Coordination

P/2019 LD2 (ATLAS) is a recently discovered active centaur, on an unstable orbit that is evolving towards the inner solar system and a potential future as a Jupiter Family Comet. This object presents a unique opportunity, which enables us to monitor a Centaur as its activity evolves and it transitions to an inner solar system object for what is likely the first time. LD2 is currently (and starting April/May 2021) observable as a northern hemisphere nighttime object at ~18th visual magnitude. It is a high priority target for characterization of composition, continuous activity and outbursts.

We encourage the community - Those with planned, scheduled or completed observations - to participate in a observing campaign coordination, through the following webpage:

The webpage includes a short observing record form. Note that signing up here does not commit anyone to sharing their data, but we hope this will become a natural gathering place for researchers to see who else will be at the telescope and when, and perhaps initiate some new collaborations.

G. Sarid, L. Woodney, M. Womack

Refereed Articles

Abstracts of articles in press or recently published. Limited to 3000 characters.

Study of the physical properties of selected active objects in the main belt and surrounding regions by broadband photometry

  • Borysenko, S. 1
  • Baransky, A. 2
  • Kuehrt, E. 3
  • Hellmich, S. 3
  • Mottola, S. 3
  • Meech, K. 4
  1. Main Astronomical Observatory of NAS of Ukraine, Akademika Zabolotnoho Str. 27, 03143 Kyiv, Ukraine
  2. Astronomical Observatory of Taras Shevchenko National University of Kyiv, Observatorna Str. 3, 04053 Kyiv, Ukraine
  3. DLR-German Aerospace Center, Institute of Planetary Research, Rutherfordstr. 2, 12489 Berlin, Germany
  4. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA

Dynamically different groups of comets and active asteroids with orbits at 2 - 5 a.u. show dust activity in varying degrees and forms. Photometric study and comparison of physical parameters can help to classify mechanisms and nature of the activity for such objects. We present new observations using broadband photometry of 15 active objects in the main asteroid belt and surrounding regions obtained during 2012 - 2016. The study aims to compare the physical properties of main-belt comets (MBCs), quasi-Hilda comets (QHCs), and active asteroids (AAs). The observations were carried out with the 0.7-m telescope of the Kyiv Comet Station, Ukraine, and with the 1.23-m telescope at the Calar Alto Observatory, Spain, using BVR broadband filters. Upper limits for the nuclear radii, Afrho parameters, and color indices were measured. The results of 2012 - 2016 observations suggest that there exist systematic differences in the physical parameters of MBCs and QHCs.

Astronomische Nachrichten (In press)

DOI: 10.1002/asna.202013765 arXiv: 2011.13247