Program and Invited Speakers

Essential Questions

Some of the questions that we will address include:

• What is the current state of our knowledge of stellar ages and how can we improve on that?
• How do we calibrate ages of systems and ensembles of stars, and what limits our ability to do so?
• What are current limits in the input physics for stellar models?
• How well can observations be matched to the models? How well can we model real spectra?
• How well do we, in fact, know the ages of ensembles and systems of stars? What limits the accuracy and precision of calculating and fitting isochrones for all kinds of stars at all stages of evolution? In other words, how well can we test and calibrate our models? To what extent does internal evolution within clusters limit us (e.g., blue stragglers)?
• What evidence is there for age spreads within systems and ensembles? How well does the lithium depletion boundary at the low end of the main sequence tell us ages?
• How good are ages of ensembles determined from tracing back kinematics?
• Can the morphology of the horizontal branch be used to determine ages?
• What do binary star systems tell us about ages and how can they help test models?
• Can we reach a point where we can reliably measure an accurate age for a single star in the field? How well does the nascent field of asteroseismology offer an independent means of determining ages?

Applying Knowledge of Ages

These subjects then lead to the essential question of the symposium: how well can we estimate the age of a single star or of groups of stars such as populations in nearby (resolved) stellar systems? Ages of stars can then be applied to some key astrophysical questions:

• How old are the primary components of our Galaxy; the thick disk and the thin disk; and over what span of time did they form? For instance, stars of the thick disk can be selected kinematically and from abundances of their alpha elements, but we need better and independent estimates of their ages.
• Over what span of time do stars within a cluster form?
• How old are the stars that have planets? In addition to the effect recently shown, in which metal- rich stars tend to be more likely to have planets, is there an age effect?
• How about the ages of stars with observed debris disks or other circumstellar material?
• Can we establish a well-defined comparison sample for the Sun, based on mass and age, so that we have a context for understanding long- and short-term changes in solar luminosity and activity?
• Are clusters, especially old ones, in fact representative of stars in the field? Or have they managed to survive as clusters because of different initial conditions?
• How well can we derive the star formation histories of composite systems such as the Local Group galaxies?
• How well can we extend our experience in our Galaxy to more distant realms, such as the halo of Andromeda, and what do we learn about the Milky Way as a result?

Invited speakers include:

• Sydney Barnes, Lowell Observatory
• Carla Cacciari, Osservatorio Astronomico di Bologna
• Marcio Catelan, Catholic University
• Brian Chaboyer, Dartmouth College
• Jorgen Christensen-Dalsgaard, University of Aarhus
• Francesca D'Antona, Osservatorio Astronomico di Roma
• Thibaut Decressin, Argelander-Institut für Astronomie, Bonn
• Sofia Feltzing, Lund Observatory
• David Fernández, Universitat de Barcelona
• Carme Gallart, Instituto de Astrofisica de Canarias
• Edward Guinan, Villanova University
• Vanessa Hill, Observatoire de Paris-Meudon
• Lynne Hillenbrand, California Institute of Technology
• Jonathan Irwin, IOA Cambridge
• Jason Kalirai, University of California, Santa Cruz
• Yveline Lebreton, Observatorire de Paris-Meudon
• Eric Mamajek, Harvard-Smithsonian Center for Astrophysics
• Robert Mathieu, University of Wisconsin at Madison
• Francesca Matteucci, Universitâ di Trieste
• Michael Meyer, Steward Observatory
• Georges Meynet, Observatoire de Geneve
• Dante Minniti, Pontifica Universidad Católica de Chile
• Ralph Neuhaeuser, University of Jena
• Francesco Palla, Arcetri Observatory
• Marc Pinsonneault, Ohio State University
• Giampaolo Piotto, Università di Padova
• Maurizio Salaris, Liverpool John Moores University
• Ata Sarajedini, University of Florida
• Peter Stetson, Dominion Astrophysical Observatory
• Genya Takeda, Northwestern University
• Monica Tosi, Osservatorio Astronomico di Bologna
• Andrew West, University of California, Berkeley

Scientific Organizing Committee

• David R. Soderblom (STScI), Chair
• H.M. Antia (Tata Institute for Fundamental Research)
• Nobuo Arimoto (National Astronomical Observatory of Japan)
• Michael S. Bessell (Mount Stromlo Observatory, ANU)
• Corinne Charbonnel (Observatoire of Geneve)
• Vanessa Hill (Observatoire de Paris, GEPI)
• Lynne Hillenbrand (Caltech)
• Birgitta Nordström (Niels Bohr Institute)
• Helio J. Rocha-Pinto (University of Virginia)
• Eline Tolstoy (Kapteyn Astronomical Institute)
• Don A. VandenBerg (University of Victoria)
• Rosemary Wyse (Johns Hopkins University)
• Manuela Zoccali (Universidad Católica de Chile)

Local Organizing Committee

• Jeff Valenti, Chair
• Jay Anderson
• Luigi Bedin
• Thomas Brown
• Roelof de Jong
• Katrina Exter
• I. Neill Reid
• Massimo Robberto
• Eva Villaver

Proceedings Editors

• Eric E. Mamajek, Harvard-Smithsonian Center for Astrophysics
• David R. Soderblom, Space Telescope Science Institute
• Rosemary Wyse, Johns Hopkins University