Full ​​​​​Comet Environment Working Group (CEWG) Meeting

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2025

1) 23rd January 2025, online, ~30 people

  1. INTRODUCTION

Elena welcomes the participants and introduces the meeting. First meeting of the year 2025. Soon the new IDS will be appointed. Overview of the last sub-WG meetings since the last Full CEWG, which took place during the Comet-I SWT on the last November in ESTEC.

  1. REPORTS from sub-Working Groups:
  1. Nucleus WG (Aurelie): In her working groups they have decided on what topics to concentrate in the following months/years - Nucleus rotation - Processes [cometary activities /brightness]
  2. Near-Environment WG (Jean-Baptiste): Ivano's phase function paper made good progresses The next version will be issued next week
  3. Far-Environment WG (Charlotte): Some superposition on the activities with the target working group to be resolved

  1. Discussion

Elena highlights that is important to prioritize the interactions with the instrument leads (for the models?).

  1. NEXT Meetings & Conferences

The next Full team meeting will be in ESTEC 31 March - 1 April, during the #6 Comet-I SWT. For all the other meeting list, see slides.

Conferences:

  • EPSC-DPS Helsinki September; Discussion with Colin about proposal of sessions related to comets and the Comet Interceptor mission;
  • Dust meeting in Venice, Giovanna Rinaldi explains the organization, venue, deadline for talk titles, and registration.
  • Oort Workshop in Stockolm (a couple of people will participate)

  1. REMINDER of the Special Issues deadlines

  1. AOB

 

2) 27th March 2025, online, ~30 people

  1. INTRODUCTION

Elena welcomes the participants and introduces the meeting. This is the second meeting of the year 2025, and new changes in the team has occurred. The new IDS for the Comet Environment WG was recently appointed, and is Sonia Fornasier, from the Université Paris Cité. Furthermore, Raphael Marschall took over the chairing of Near-Environment sub-WG or few months.

Overview of the last sub-WG meetings since the last Full CEWG (23rd January 2025).

  1. REPORTS from sub-Working Groups:
  1. Nucleus WG (Aurelie): Main topic of research are characterizing cometary brightning and make prediction on how it varies with solar distance. Any modelling activity should be kept simple in the first investigation, and the outputs should be compared and fitted to observational data.
  2. Near-Environment WG (Raphael): Ivano's phase function paper was submitted to the PSS Sp. Issue. It includes the development of a composite phase function for the dust, obtained with a compound Henyey-Greenstein curve and compared it with previous models which were not including recent literature data constituting fine follow-ups of comets at small and large phase angles.
  3. Far-Environment WG (Charlotte): Focus is comparing different simulations and verifying which are best suited for a given scenario, with the goal of a better understanding of the outputs vs. the input assumptions.

  1. Dust Meeting (18-20 March, 2025 in Venice)

Giovanna presented a short overview about the Dust meeting. The scientific programme was distributed over seven sessions, and consisted on talks investigating cometary dust from the observational, modelling, and laboratory analysis approaches. Of importance was the round table for each dedicated topic. A theather art perfomance developed by Stavro was part of the meeting. Next one will be on March 2026, in Graz (Austria).

  1. Discussion

Elena highlights that is important to prioritize the cooperation between the various sub-groups to improve our predictive cometary activity by means of multiple models, and strengthen the interactions with the instrument leads.

  1. NEXT Meetings & Conferences

This Full team meeting is in replace of the one usually taking place during the Comet-I SWT. In the week after (31 March - 1 April), a summary report during the #6 Comet-I SWT in ESTEC will be given. For the list on next meeting and conferences, see meeting slides.

  1. Special Issues

It is still under debate the possibility of an extention of the deadline for the Universe journal (refer to Stavro Ivanovski)

  1. AOB

 

3) 26th June 2025, online, up to 37 people

  1. INTRODUCTION

Elena welcomes the participants, and Sonia introduces herself and her project as IDS within the Comet Environment WG. This is the third meeting of the year 2025, and the last one before the summer break. A quick introduction of all the meetings over the past year was given (Fig. 1).

Fig. 1. Overview of the meetings, seminars, and workshops in the Oct. 2024 - June 2025 period.

 

  1. PRESENTATIONS from sub-Working Groups:​​​​​​​

Chairs (A. Guilbert-Lepoutre, R. Marchall for J.-B. Vincent, and C. Goetz) briefly introduced the main current research topics of their sub-groups, and the stage was then left to the team members, to shortly present to the audience their recent and up-coming research and results. The different meeting format was also conceived to allow a better spread of the hot-topic in the cometary field and favour a deeper collaborations between the three sub-groups. In Fig. 2, the list of the speaker, whereas for a more detailed outline of the presentations, see the circulated pdf.
 

Fig. 2. Agenda with the list of the meeting speakers..

Additionall​​​​​​​y, also Andris Slavinskis presented. He is part of a research team under an ESA contract, having the goal of carrying out modelling to support future acquisitions of instruments like OPIC, MIRMIS NIR, and EnVisS. He provided also the links about their modelling outputs:

https://zenodo.org/records/15111943

https://space-travel.blog/ci3d-flow-3d136b7baafc

https://drive.google.com/file/d/1utwZuGlZGpqZZwkSdoAXK6mfHIbrL4Je/view

https://bitbucket.org/planetarysystemresearch/asteroid-image-simulator/branch/ci3d

 

  1. Closing Remarks

     Publications overview, available in the pdf.

 

  1. AOB and Discussion

Elena prioritized again the importance of cooperation between the various sub-groups to improve the systematic prediction of cometary behaviour and characterizations.

It is important to recall that there are several live documents: in addition to the simple/engineering models collection, there are (1) the instruments constraints during fly-by fulfilling the science requirements (contact person: Arnaud Beth), and (2) cometary parameters for systematic simulations (contact person: Herbert Gunell).

Next possible CEWG meeting can likely take place in person, during the EPSC-DPS 2025 meeting in Helsinki, in conjunction with the TIWG. Save the date for the CI SWT (27-28 October), and for the Dust Workshop (17-19 March 2026).

 

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EPSC-DPS 2025, Helsinki, Finland.

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