Cool Stars 23

15 – 19 June 2026, TOC Ariake, Tokyo Bay Area, Japan

The "Cambridge Workshops on Cool Stars, Stellar Systems and the Sun" are held biennially and have evolved to be the premier conference series for cool star research.

Splinter sessions are going to be held on Monday, Tuesday, and Thursday afternoon (the dates listed are nominal and subject to change until 3 months prior to the conference). There will be three splinter sessions in parallel. These sessions are organized separately from the main conference. Each splinter session will have its own website with contact information for contributors. The websites will be linked from the splinter session title in the list below when they are available. Splinter session organizers can set their own deadlines for contributions to their sessions.

Monday

1. Open Clusters as laboratories for cool star evolution
   Deepak Chahal, Beatrice Caccherano, Ed Gillen (Queen Mary University of London), Rob Jeffries (Keele University), Dario Fritzewski (KU Leuven)
2. Young Stars with Evolving Planetary Systems
   Norio Narita (University of Tokyo), John Livingston (Astrobiology Center, Japan), Kiyoe Kawauchi (Ritsumeikan, Japan), Enric Palle (Instituto de Astrofisica de Canarias), Jaume Orell-Miquel (University of Texas at Austin), Eric Gaidos, Fei Dai (University of Hawaii)
3. The coolest massive stars: winds, companions, and the aftermath of red supergiants
   Elvire De Beck (Chalmers University of Technology), Miguel Montargès (Paris Observatory), Markus Wittkowski (ESO), Emma Beasor (Liverpool John Moores University), Lee Patrick (Astrobiology Centre, Spain)

Tuesday

4. Connecting Granulation and Magnetic Activity in Radial Velocities: The Next Breakthrough for High-Precision Spectroscopy
   Ancy Anna John, Federica Rescigno (University of Birmingham), Khaled Al Moulla, Carmen San Nicolas Martinez (Center for Astrophysics at the University of Porto), Thomas Wilson (University of Warwick), Nadège Meunier (Institut de Planétologie et d’Astrophysique de Grenoble), Andrew Collier Cameron (University of St. Andrews), Sophia Sulis (Laboratoire d’Astrophysique de Marseille)
5. Connecting Cool Dwarfs' Stellar Chemistry to Exoplanet Structure and Atmospheres
   Diogo Souto (Federal University of Sergipe), Katia Cunha (Steward Observatory), Nuno Santos (Instituto de Astrofísica e Ciências do Espaço), Rafael Luque (Instituto de Astrofísica de Andalucía), Enric Palle (Instituto de Astrofísica de Canarias), Ian Crossfield (University of Kansas), Yui Kawashima (Kyoto University, Japan), Verne Smith (NOIRLab)
6. (Tentative title) Multiple systems among cool stars and their evolution
   Leen Decin (KU Leuven), Matthew I. Swayne (University of Glasgow), Orsola De Marco (Macquarie University), Pierre Kervella (Observatoire de Paris), Dorota Skowron (University of Warsaw), Theo Khouri (Chalmers University), Ayush Moharana (Keele University), Nikki J. Miller (Uppsala University), José A. Caballero (Centro de Astrobiología, Madrid), Krzysztof G. Helminiak (N. Copernicus Astronomical Center, Toruń), Thibault Merle (Université Libre de Bruxelles & Royal Observatory of Belgium), Valentin D. Ivanov (ESO, Garching), Swetlana Hubrig (Leibniz-Institut für Astrophysik Potsdam)

Thursday

7. Rotation and Magnetism off the Main Sequence
   Joel Ong (University of Sydney), Li Yaguang (University of Hawaii), Sébastien Deheuvels (IRAP Toulouse), Rachael Roettenbacher (University of Michigan)
8. Dissecting clouds and atmospheres of the coldest substellar worlds with JWST
   Emily Rickman (ESA/STScI), Daniella Bardalez Gagliuffi (Amherst), Elena Manjavacas, Julien Girard (STScI)
9. From Grains to Galaxies: Dust from Evolved Stars—Bridging Hydrodynamics, Chemistry, and Observations
   Matthias Maercker, Theo Khouri (Chalmers University of Technology)

The CS23 SOC invites the community to propose splinter sessions on current hot topics. Proposals for splinter sessions can be made by individuals or groups of individuals. At this time, we are planning on 9 splinter sessions. Each session is 180 minutes long.

Splinter organizers should be prepared to produce and maintain a website that includes the schedule and speakers, and describes opportunities for people to participate in the session. The splinter websites will be linked from the main CS23 website, so all meeting participants are aware of the splinter sessions and can make informed choices about which sessions they wish to attend. A complete program for each splinter should be online six weeks prior to the meeting, that is by May 1st, 2026 - and hopefully earlier.

Note that CS23 follows a "one person - one talk" rule. Plenary speakers cannot give a talk in a splinter session, nor can one person present in more than one splinter session. The list of plenary speakers will be shared with the splinter organizers once it is finalized.

Any splinter session proposal should include the following:

1. Title
2. Names of the session organizers with primary contact information; names of co-organizers if appropriate
3. Estimate of small (50-100 people), medium (100-200), or large (200+ people) session
4. Two page summary of the goal of the session, including discussion on why this is a timely and relevant topic for CS23
5. List of potential speakers, and a plan for how additional speakers will be solicited (Note that CS23 follows a "one person - one talk" rule. Plenary speakers cannot give a talk in a splinter session, nor can one person present in more than one splinters session.)
6. Proposed Splinter format that includes a description on how the audience will be involved
7. Commitment to set up a website in support of the splinter, with a complete program online by May 1st, 2026
8. Commitment to contribute a summary of the session for the proceedings

Please do not propose splinters that are too similar to the five main morning sessions (see the conference program) if you wish to maximize your chances of success.

Deadline for splinter session proposals is November 3rd, 2025. Instructions for splinter proposal submissions can be found at this Google Form.

We plan to announce accepted splinter sessions by mid-December January, 2026, and will provide links to your splinter session website for attendees to submit contributions to your splinter as soon as possible.