Ringberg Meeting: Puzzles of Star Formation II

May  4-7, 2025


Scope of the meeting

Welcome to this workshop to explore the boundaries and puzzles in the field of star formation. This is the second incarnation of the Puzzles of Star Formation meeting (PoSFII), where the first edition took place at Ringberg castle in 2021. We do not anticipate the classical meeting where everybody presents and summarizes the most recent results, but rather we would like to dig deeper and decipher the real problems in the field that still need to be solved.

Star formation is a topic of active research since the seventies and a lot of progress has certainly been made since then. Nevertheless, there are still many conceptual issues and central puzzles that are not solved yet. These include processes and physics related to the origin of turbulence in the ISM, the formation, evolution and lifetimes of molecular clouds in the turbulent environment of galaxies, the condensation of these clouds into stars, multiple systems and stellar clusters via gravitational collapse and the energetic processes by which these stars affect their gaseous environment and by this self-regulate star formation. With this meeting we want to make an attempt to identify and clarify some of the most pending questions in the field, and to seek paths to solve them, from a theoretical as well as observational point of view.

This requires a new workshop style that is not focused primarily on presentations of most recent insights and successes but, just on the opposite, about what you think is fascinating but not understood, why it is important and (if you have an idea) suggestions of how to solve the puzzle, maybe in a concerted effort. Your task as participant will be to suggest such questions and lead a subsequent discussion.

Approach

With an anticipated 40 participants, there is sufficient room for various forms of discussions. Every participant has a 20min slot where an important question or puzzle in the field can be introduced and a discussion be started. In this 20min slot, a maximum of 10min should be devoted to introduce the topic/question and/or show some initial results. The remaining part of the time should be dedicated to discussion. Furthermore, it is possible to "cumulate" slots. Check out the list of participants below. If you want to introduce/discuss a question/puzzle with another participant, two or three slots can be cumulated to 40min or 60min slots. The share of 50% intro/results and 50% discussion should remain.

We are looking forward to a lively and exciting meeting!


Program

Sunday, May 4, 2025: Afternoon and early evening: Arrival at castle

18:30             Dinner

Monday, May 5, 2025
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Chair: Eve Ostriker

09:00 - 09:20 Andreas Burkert & Henrik Beuther: Welcome and Introduction
09:20 - 09:40 Neil Evans: How does the Milky Way compare to, and illuminate, the molecular gas and star formation properties of other galaxies?
09:40 - 10:00 Sophia Stuber: The puzzling extragalactic dense gas view
10:00 - 10:20 Alvaro Hacar: How can we characterise the hierarchical structure of the ISM?

10:20 - 10:50 Coffee break

10:50 - 11:30 Philippe Andre & Michael Mattern: Are star-forming moelcular clouds really hierarchical and scale-free?
11:30 - 12:10 Steffi Walch-Gassner & Vittoria Brugaletta: Star formation in the multi-phase ISM

12:30-14:30 Lunch break & discussion sub-groups

Chair: Sam Pearson

14:30 - 14:50 Eva Schinnerer: What mechanism(s) is inhibiting the formation of massive stars in central molecular gas reservoirs?
14:50 - 15:10 Veena Vadamattom: Bar fights and a smoking chimney - The Galactic Centre's star formation struggle
15:10 - 15:30 Juan Soler: How are star-forming clouds connected to the diffuse ISM?
15:30 - 15:50 Andrea Socci: Shaping filaments: the role of the interstellar environment

15:50-16:20 Coffee break

16:20 - 16:40 Alice Nucara: Which magnetic field scale(s) are most responsible for regulating star formation? from the initial clump formation to its evolution and eventual fragmentation into protostellar objects?
16:40 - 17:00 Henrik Beuther: How do magnetic fields and dynamics influence each other?
17:00 - 17:20 Maria Jose Maureira: Are gravitational  unstable disks common during the embedded stages?

17:30        Castle tour

18:30       Dinner

Tuesday, May 6, 2025
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Chair: Neal Evans

09:00 - 09:20 Arshia Jacob: HI-to-H2 transition
09:20 - 09:40 Alyssa Goodman: How do young stars "leave home," and why might that matter?
09:40 - 10:00 Molly Wells: What Secrets Do Accretion Flows Hold in the Formation of Stars?
10:00 - 10:20 Friedrich Wyrowski: Gas flows from cloud to core scales

10:20-10:50 Coffee break

10:50 - 11:30 Eve Ostriker & Sanghyuk Moon: Is there a characteristic mass for star formation?
11:30 - 11:50 Thomas Henning: What regulates the mass of a star?
11:50 - 12:10 Adam Ginsburg: How do the most massive stars form? (What bounds the IMF?)

12:30-14:30 Lunch break & discussion sub-groups

Chair: Alison Young

14:30 - 14:50 Peter Schilke: Mapping the diversity of Star Formation
14:50 - 15:10 Chiara Minini: How does infall evolve at different scales and which tracers to use?
15:10 - 15:30 Sarwar Khan: Early stage of HII regions and methanol maser
15:30 - 15:50 Simon Reyes: Measuring accretion rates onto high-mass protostars

15:50-16:20 Coffee break

16:20-16:40 Beth Jones: Is precision astrophysics possible against the complexity of star forming cores?
16:40-17:20 Jaime Pineda & Maria Teresa Valdivia-Mena: Are the physical processes shaping molecular clouds affecting disk formation and evolution?
17:20-17:40 Matthew Bate: The impact of stellar core formation on young, massive protostellar discs
17:40-18:00 Theo Richardson: Which theories of star formation fit the observations?

18:30       Dinner

Wednesday, May 7, 2025
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Chair: Steffi Walch

09:00 - 09:20 Macla Ramirez-Tannus: The formation of close massive binaries
09:20 - 09:40 Wolfgang Brandner: The “curious” case of the anti-correlation between the sub-100 au solar-type binary frequency and metallicity
09:40 - 10:00 Sam Pearson: Infrared Spectra of Young Planetary Mass Objects: Models vs. Standard Spectra
10:00 - 10:20 Mark McCaughrean: What do we really see in jets and outflows?

10:20 - 10:50 Coffee break

10:50 - 11:10 Alison Young: Where are the first hydrostatic cores?
11:10 - 11:30 Hans Zinnecker: Star formation near the Galactic center SMBH
11:30 - 12:10 Stefan Heigl & Andreas Burkert: Can turbulence delay collapse?

12:30 - 14:00 Lunch

Afterwards: Departure

List of participants

Philippe Andre
Matthew Bate
Henrik Beuther
Wolfgang Brandner
Vittoria Brugaletta
Andreas Burkert
Neil Evans
Adam Ginsburg
Alyssa Goodman
Alvaro Hacar
Stefan Heigl
Thomas Henning
Arshia Jacob
Beth Jones
Sarwar Khan
Michael Mattern
Maria Jose Maureira
Mark McCaughrean
Chiara Mininni
Sanghyuk Moon
Alice Nucara
Eve Ostriker
Sam Pearson
Thushara Pillai
Jaime Pineda
Maria Claudia Ramirez-Tannus
Simon Reyes
Theo Richardson
Peter Schilke
Eva Schinnerer
Andrea Socci
Juan Soler
Sophia Stuber
Veena Vadamatton
Maria Teresa Valdivia-Mena
Steffanie Walch
Molly Wells
Friedrich Wyrowski
Alison Young
Hans Zinnecker