Abstract

The new generation of instruments (JWST, IRAM, ALMA, and soon SKA) is ushering in an unprecedented era for the study of molecular tracers by revealing surprising chemical complexity in the interstellar medium, circumstellar envelopes, comets, and exoplanetary atmospheres. Analyzing these observations requires access to an ever-increasing amount of fundamental physics data (spectroscopy, collisions, chemical reaction constants) as well as state-of-the-art numerical models that use this data to simulate the processes occurring in the systems under study. One change compared to previous years is the rapid increase in the complexity of the data that must be analyzed: reaction efficiency as a function of the quantum states of the products, photoprocesses with wavelength-selective effects, reaction rates depending on the nature of the ice matrices, etc. Stronger coordination among data producers, the agencies that disseminate the data, the data scientists who incorporate it into models, and the analysts who make use of it all is essential to fully leverage the observations from the new large-scale instruments and address scientific challenges. 
The workshop (June 8–11, Saint-Florent) will bring together physicists, chemists, and astrophysicists, as well as representatives from the National Observation Services responsible for data dissemination. Its goal is to assess current needs, prioritize efforts, and define shared strategies for the production and dissemination of molecular data. Two roundtable discussions will provide an opportunity to discuss the operational aspects of data dissemination and the needs of modelers. A final summary will be shared with the community through the PN Astro thematic initiatives, with a particular focus on involving young researchers.

Scientific justification

New generations of instruments (JWST, IRAM, ALMA, and soon SKA) are providing an ever-increasing amount of spectroscopic data. Their sensitivity has already made it possible to detect more than 300 molecules in the interstellar medium and circumstellar envelopes, including complex species. Deep surveys (e.g., QUIJOTE in TMC1) thus reveal hundreds of spectral lines and an unexpected chemical richness. At the same time, observations of comets and planetary atmospheres are deepening our understanding of their chemical complexity. Measurements of abundance, isotopic fractionation, and molecular excitation are key diagnostic tools for studying physical processes and tracing the history of stellar and planetary formation, including that of exoplanets. Finally, the detection of more than 70 extragalactic molecules highlights the growing importance of new molecular tracers for studying galaxies and gas at high redshifts. A major breakthrough is the ability to access highly excited quantum states. The JWST (MIRI, NIRSPEC) detects numerous H₂ transitions up to v = 6 (and up to v = 13 with IGRINS), as well as similar lines for CO and other species in certain environments. Radio lines from atomic recombination are also becoming more accessible (NenuFAR, followed by SKA).

However, the scientific analysis of this data requires state-of-the-art numerical astrochemical models (that account for chemistry and excitation) and a wealth of physical data (spectroscopy, collision rates, reaction constants, etc.). These data come from laboratory experiments and complex calculations carried out by physicists and chemists; they are costly to produce and can sometimes be complex to use. Reference databases (KIDA, EMAA) and e-infrastructures (VAMDC) therefore play a key role in cataloging, documenting, and formatting these data to facilitate their access and use by astrophysicists. Several challenges are emerging: the rapid increase in data requirements as instruments become more sensitive; the need to prioritize the systems to be studied and to define acceptable approximations; and the increasing complexity of the expected data (e.g., it is becoming increasingly necessary to have chemical reaction rates as functions of quantum states). For example, it is crucial to consider the excited state of H₂ in certain reactions to explain the intensity of spectral lines from molecules such as CH⁺, SH⁺, or excited CO in irradiated environments; Similarly, accounting for quantum states in the photodissociation of H₂O to produce OH is necessary to interpret the excitation observed in disks, and these processes are now being explored in cometary atmospheres.

To address these challenges, a workshop is being organized to bring together data producers, heads of national observation services and data dissemination infrastructures (KIDA, EMAA, VAMDC), teams providing interpretation tools (MIS & Jets Platform, CASSIS, Meudon PDR Code, etc.), as well as modelers and observers. Each participant will present their work and needs; the goal is to take stock of the current situation, coordinate efforts, and discuss the methods for disseminating data. Two roundtable discussions will address, in concrete terms, the dissemination of molecular physics data and the needs of modelers and observers. A closing discussion will summarize the exchanges, and a summary of the discussion will be shared with the community via the PN Astro mailing lists, with a strong focus on young researchers.

This workshop will bring together astrophysicists, physicists, and chemists. We will also ensure that representatives from the relevant National Observatories (SNO) are invited. For example, three SNOs from the Paris Observatory will be in attendance (VAMDC, MIS & Jets Platform, and the PDR Code in Meudon). For this first edition, we’re expecting just over forty people. Several invitations will be sent out in October to ensure the participation of several key teams in the French scene.

The workshop will take place from June 8 to 11 in Saint Florent, Corsica. It will be hosted by CESM Saint Florent, a nonprofit organization under the French Law of 1901. The workshop will follow a format very similar to that of the biannual workshops on “physicochemical processes of astrophysical interest” regularly organized by some of the organizers (F. Lique & A. Faure). Given the workshop’s location and the relative difficulty of getting there, all participants will attend every session. Organizing group meals will encourage interaction and discussion among participants.

Preliminary program

Monday, June 8
11:00 a.m. – 12:00 p.m. Registration
12:15 p.m. – 1:15 p.m. Lunch
1:30 p.m. – 5:30 p.m. Presentations
7:30 p.m. – 9:00 p.m. Cocktail reception / dinner

Tuesday, June 9
9:00 a.m. – 12:15 p.m. Presentations
12:30 p.m. – 1:30 p.m. Lunch
1:30 p.m. – 5:00 p.m. Break
5:00 p.m. – 7:30 p.m. Presentations

Wednesday, June 10
9:00 a.m. – 12:15 p.m. Presentations
12:30 p.m. – 1:30 p.m. Lunch
1:30 p.m. – 5:00 p.m. Break
5:00 p.m. – 7:30 p.m. Roundtable Discussion
7:30 p.m. – 9:30 p.m. Conference Dinner

Thursday, June 11
9:00 a.m. – 11:30 a.m. Presentations
11:30 a.m. – 12:30 p.m. Discussions
1:30 p.m. – 6:00 p.m. Tour of the Agriates Desert