WORKSHOP: Unstable and Time-Variable Accretion Flows from Core to Disk to Star

Special Events // September 16, 2025 //

Recent observations and simulations have revealed various non-smooth and irregular structures on both the prenatal core and the protoplanetary disk scales (e.g. streamers, arcs, rings, and cavities). The central forming stars and the outflows also reveal episodic signatures. Combined, these observational results imply that star formation is not as smooth and orderly as suggested by the ‘standard model’.

This workshop aims to bring together a diverse group of observers and theorists to discuss unstable and time-variable stellar mass assembly. We will explore the significance of the observed complex structures and flow patterns in determining the outcome of star formation and identify key observational diagnostics and theoretical tests that will advance our understanding of the underlying physical processes.

The goal of the meeting is to plan out and put together a future-looking white paper to highlight the key observational diagnostics needed to answer the big questions in the field.

Format: Up to 30 participants (by invitation). While there is no registration fee, we cannot provide additional financial support to attendees. See CITA hotel guide.

FULL SCHEDULE and TALK ABSTRACTS


The WORKSHOP is running from October 15 through October 17 at CITA's Flagship location at the University of Toronto in Canada.

Address: 60 St. George Street, McLennan Physical Laboratories, 13 floor, IdeaLab

Organizers: Shantanu Basu (CITA), Doug Johnstone (NRC-HAA)

Topics:

Core collapse (substructure/streamers)
Disk formation and evolution (magnetic braking, disk spreading)
Disk accretion (viscosity/MHD winds/MRI/instabilities)
Protostellar accretion (magnetospheric accretion/diagnostics)
Episodic accretion (mechanisms, monitoring, chemistry, bullets)

Confirmed participants (evolving list):

Hector Arce (Yale)

Asmita Bhandare (LMU)

Shantanu Basu (CITA)

Carlos Contreras (SNU)

Michael Cecil (Heidelberg)

Indrani Das (ASIAA)

Eleonora Fiorellino (Bologna)

Doug Johnstone (NRC-HAA)

Kundan Kadam (IWF, Graz)

Rajika Kuruwita (Heidelberg)

Jeong-Eun Lee (SNU)

Nagayoshi Ohashi (ASIAA)

Yuki Okoda (NRC-HAA)

Ralph Pudritz (McMaster)

Hsien Shang (ASIAA)

Ayumu Soshi (Kyushu)

Michihiro Takami (ASIAA)

Shinsuke Takasao (Musashino)

Kazuki Tokuda (Kagawa)

Yisheng Tu (Michigan)

Han-Gyeol Yun (SNU)

Guillermo Blázquez Calero (IoA Andalucia)

Paulo Cortes (ALMA Obs)

Rahul Khanna (Western)

Majd Noel (Western)