Home Program Information

Block 1

14:00 Multiplicity of cool stars - Current Developments and Challenges
A foreword by the organisers.
14:05 PLENARY TALK 1 - Detecting companions around cool stars
Dr Léa Planquart (Chalmers University of Technology)
Several methods exist to detect (sub)stellar companions and extract their orbital elements, a key ingredient for understanding their evolution. When applied to cool stars with dynamic and complex atmospheres, additional challenges arise in disentangling the orbital signature of a faint companion from the intrinsic variability of the primary star. In this talk, I will review the different observational techniques for characterizing the orbits and the interaction imprints of companions around cool stars, along with their caveats. Their complementary power will be highlighted through illustrative examples, and I will emphasize the potential of upcoming large-scale survey releases to characterize the multiplicity of cool stars, from exoplanets to black-hole companions.
14:20 PLENARY TALK 2
Dr Natalie Gosnell (Colorado College)
Full abstract to come.
14:35 Contributed Talks
Alexandra Boone (University of Wyoming) - 'Fundamental Parameters of Low-Mass Doubly Eclipsing SB2 Binaries'

Florian Driessen (KU Leuven) - 'Mass loss in AGB binary systems'

Mark Giovinazzi (Amherst College) - 'A Volume-limited Sample of Companions to Accelerating Stars from Hipparcos and Gaia'

Michael Greklek-McKeon (Carnegie Science, Earth & Planets Laboratory) - 'Confirmation of three Earth-sized planets in the most compact known planet-hosting M-dwarf binary'

Axel Hahlin (Keele University) - 'Characterisation of eclipsing binary benchmark stars and their M-dwarf companions'

Fabian Kaczmarek (Astronomical Observatory Institute, Adam Mickiewicz University in Poznań) - 'Insights on binary stars from interferometric observations'

Jaroslav Merc (Astronomical Institute of Charles University) - 'Probing stellar interaction in cool stars beyond the Roche lobe overflow'
7 submitted talks on emerging results or open questions in Cool Stellar Multiplicity
15:10 PLENARY TALK 3 - Binary interactions with evolved giants and their progeny
Dr Onno Pols (Radboud Universiteit)
In this talk I will discuss stellar systems that have previously undergone binary interaction with an evolved giant: post-RGB and post-AGB binaries, chemically polluted stars, and related systems.  I will focus on what their currently observed properties (orbital parameters, surface abundances etc) can tell us about the past interaction with an RGB or AGB star, and discuss the physical processes (such as tides, stellar winds and mass transfer) that shape this interaction, with insights from hydrodynamic simulations and detailed binary evolution modelling. I will also highlight the many open questions in this field.
15:25 Poster-Pop
Thomas Baycroft - Tsung-Dao Lee Institute, Shanghai Jiao Tong University
Gemma Cheng - University of Hertfordshire
Matthew De Furio - University of Texas at Austin
Kunal Mehta - University of Michigan Ann Arbor
Sean Ivor Mills - Maynooth University
Ayush Moharana - Keele University
Benjamin Tofflemire - SETI Institute
Maximiliano Dirk Vega Aguilera - University of Hertfordshire
Rebecca Woody - Center for Astrophysics | Harvard & Smithsonian
Short 30 second poster-pops to highlight related posters before coffee break.
15:30 Coffee & Tea Break

Block 2

16:00 Preparing for the future - Future missions and Cool Stars Multiplicity
A foreword by the organisers.
16:05 PLENARY TALK 4 - Binary Stars and RR Lyrae Variables with the Vera Rubin Observatory's LSST: Preparing for a New Era of Cool Star Science
Kelly Hambleton (Villanova University)
The Vera Rubin Observatory's Legacy Survey of Space and Time (LSST) is poised to transform cool star variable science. With its unprecedented combination of depth, multiband photometry, and ten-year temporal baseline, LSST will detect vast numbers of eclipsing, ellipsoidal, and pulsating variables across the southern sky. Binary stars and RR Lyrae variables represent two of the most compelling cool star science cases for LSST: the former benefiting from LSST's depth and multiband photometry to unlock faint, low-mass multiple systems currently out of reach, and the latter from LSST's sky coverage and color information to refine distances, metallicities, and pulsation properties across the Galaxy.

In this talk, I will outline the science case for both populations with LSST, drawing on my work leading the Pulsating Stars Subgroup and the Transients and Variable Stars Science Collaboration Roadmap. I will present early commissioning light curves from the Vera Rubin Observatory, offering a first glimpse of LSST's capabilities in practice. I will discuss our ongoing work simulating Rubin-like light curves from TESS data to realistically assess LSST's period recovery and light curve characterization capabilities for RR Lyrae variables across different cadence strategies and sky regions, alongside similar works that address binary star systems. I will also highlight how LSST's multiband photometry opens new possibilities for binary star parameter determination and RR Lyrae identification, distance refinement, and temperature characterization.
16:25 PLENARY TALK 5 - Multiplicity in cool stars: current status and looking forward to PLATO
John Southworth (Keele University).
Multiplicity is an unavoidable feature of stars: the majority have at least one companion. Multiplicity arises from the star formation process, decreases as stars age, and complicates the study of stellar populations. It also enables measurement of the basic physical properties of stars, especially their masses. Eclipsing binary systems allow stellar radii to be measured directly, yielding properties of stars that can be used to critique theoretical predictions. I will summarise the current knowledge of the multiplicity and properties of low-mass stars, then look to a future dominated by the PLATO mission. This is scheduled for launch by ESA in January 2027, will be the next great space-based planet-hunter, and will obtain high-quality light curves of hundreds of thousands of stars. A high priority with PLATO is the detection of planets around M-dwarfs - the P4 sample - because they enable the detection of smaller and cooler planets via the transit method. As a byproduct of this work, PLATO is almost certain to discover many new eclipsing cool-star binaries which we can use to improve our understanding of the most numerous stars in our galaxy.
16:45 Contributed Talks
Zachary Hartman (ORAU/ NASA Ames Research Center) - 'Updating the MUGSHOTS'

Silva Järvinen (Leibniz Institute for Astrophysics Potsdam) - 'The magnetism of interacting systems in open clusters'

Sara Muñoz Torres (Instituto de Astrofísica de Canarias) - 'A Rare Wide L/T Binary in the Field Discovery: The First Resolved Substellar System from Euclid'

Thomas Vandal (Trottier Institute for Research on Exoplanets, Université de Montréal) - 'Constraining the multiplicity of the coldest brown dwarfs down to planetary masses between 0.5 and 1000 au with JWST'
4 submitted talks with a glimpse into potential future avenues of Cool Stellar Multiplicity.
17:05 Discussion
-
The session will conclude with a panel-style dialogue highlighting the most pressing unsolved problems and opportunities for collaboration, giving early-career researchers a central role in articulating future directions.