Cometary Science Newsletter

May 2024
Michael S. P. Kelley (

Conference Announcements

Announcements for cometary conferences or workshops. Limited to 2000 characters.

Dear colleagues,

In view of the Europlanet Science Congress 2024 that will be held in Berlin, Germany, 8-13 September 2024, we invite you to submit abstracts for our interdisciplinary session: “Exploring the links between comets and protoplanetary disks (SB11)”.

Convener: Manuela Lippi; Co-conveners: Linda Podio, Colin Snodgrass, Catherine Walsh, Martin Cordiner, Raphael Marschall, Cyrielle Opitom

You can find the session description and submit your abstract at the link:

The deadline for abstract submission is 15 May 2024, 13:00 CEST; additional instructions can be found at

Please, feel free to forward this message to colleagues that may be interested in this topic, and do not hesitate to contact me if you have any further questions.

I apologise in advance for any cross-postings.

Best regards,

Manuela Lippi and the SB11 SOC

Conference on Planetary Science and Space Exploration in Daejeon, South Korea

On behalf of the local organizing committee, I would like to invite you to attend the Conference on Planetary Science and Space Exploration. It will be held at the Institute for Basic Science (Daejeon, South Korea) on July 22-25 of 2024. The conference mainly is intended (but not limited) to gather scientists participating in COSPAR-2024 (Busan, South Korea; July 13-21), those who are interested to continue discussions and further enhance networking on various topics of planetary research in a less formal regime. The conference place, city of Daejeon, is located right between Busan and the main-gate airports to Korea (Incheon and Seoul), making travel there very simple. The deadline for submission of short abstracts (300 words) is May 17 of 2024. Please, find more details on the conference, invited speakers and SOC at

Refereed Articles

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

Pre-perihelion observations of long-period comet C/2013 X1 (PANSTARRS)

  • Shubina , O. 1 , 2
  • Ivanova , O. 1 , 2 , 3
  • Petrov, D. 4
  • Luk’yanyk, I. 3
  • Rosenbush, V. 3
  • N. Kiselev, N. 4
  1. Astronomical Institute of Slovak Academy of Sciences, Slovak Republic
  2. Main Astronomical Observatory of National Academy of Sciences of Ukraine, Ukraine
  3. Astronomical Observatory of Taras Shevchenko National University of Kyiv, Ukraine
  4. Crimean Astrophysical Observatory, Crimea

We present and analyse the results of quasi-simultaneous spectroscopic, photometric, and polarimetric observations of hyperbolic comet C/2013 X1 (PANSTARRS) obtained at the 6-m Big Telescope Alt-azimuth (BTA) telescope Special Astrophysical Observatory (SAO) and 2.6-m Shajn telescope Crimean Astrophysical Observatory (CrAO). A wide fan-shaped structure and a weak tail were detected in the comet. The mean V - R colour of the coma was estimated to be neutral compared to the solar value. The Afρ parameter, a proxy to the dust production in the comet, was about 1672 ± 21 cm in the R band. Emissions of the CN, C2, C3, and NH2 molecules were identified in the cometary spectrum, which covers the wavelength range 3800 - 7100 Å. When the comet was at a distance of 2.66 au from the Sun, the minimum degree of polarization of about -1.5 per cent was detected in the near-nucleus region of the coma, in the range up to about 10 000 km from the optocentre. Further, polarization gradually increased (in absolute value) with distance from the nucleus, reaching -6.5 per cent at about 50 000 km. To reproduce the observed values of linear polarization and the phase-angle dependence of polarization for long-period comets, we used the Sh-matrix method with conjugated Gaussian random particles as light scatters, and the chemical composition of dust particles in the coma of 74 per cent amorphous carbon, 25 per cent of Mg-rich silicates, and 1 per cent of water ice.

Monthly Notices of the Royal Astronomical Society (Published)

DOI: 10.1093/mnras/stae441 NASA ADS:  2024MNRAS.528.7027S

  • Robinson, J. E. 1
  • Malamud, U. 2
  • Opitom, C. 1
  • Perets, H. 2
  • Blum, J. 3
  1. Institute for Astronomy, University of Edinburgh
  2. Department of Physics, Technion - Israel Institute of Technology
  3. Institute for Geophysics and extraterrestrial Physics, Technische Universität Braunschweig

All cometary nuclei that formed in the early Solar System incorporated radionuclides and therefore were subject to internal radiogenic heating. Previous work predicts that if comets have a pebble-pile structure internal temperature build-up is enhanced due to very low thermal conductivity, leading to internal differentiation. An internal thermal gradient causes widespread sublimation and migration of either ice condensates, or gases released from amorphous ice hosts during their crystallisation. Overall, the models predict that the degree of differentiation and re-distribution of volatile species to a shallower near-surface layer depends primarily on nucleus size. Hence, we hypothesise that cometary activity should reveal a correlation between the abundance of volatile species and the size of the nucleus. To explore this hypothesis we have conducted a thorough literature search for measurements of the composition and size of cometary nuclei, compiling these into a unified database. We report a statistically significant correlation between the measured abundance of CO/H2O and the size of cometary nuclei. We further recover the measured slope of abundance as a function of size, using a theoretical model based on our previous thermophysical models, invoking re-entrapment of outward migrating high volatility gases in the near-surface pristine amorphous ice layers. This model replicates the observed trend and supports the theory of internal differentiation of cometary nuclei by early radiogenic heating. We make our database available for future studies, and we advocate for collection of more measurements to allow more precise and statistically significant analyses to be conducted in the future.

Monthly Notices of the Royal Astronomical Society (Published)

DOI: 10.1093/mnras/stae881 NASA ADS: 2024MNRAS.tmp..921R arXiv: 2403.15644