Insights into star formation and dispersal from the synchronization of stellar clocks

Núria Miret Roig, João Alves, David Barrado, Andreas Burkert, Sebastian Ratzenböck, Ralf Konietzka

Age is one of the most fundamental parameters of stars, yet it is one of the hardest to determine as it requires modelling various aspects of stellar formation and evolution. When we compare the ages derived from isochronal and dynamical traceback methods for six young stellar associations, we find a systematic discrepancy. Specifically, dynamical traceback ages are consistently younger by an average of $\langle\Delta_{\rm Age}\rangle = 5.5 \pm 1.1$ Myr. We rule out measurement errors as the cause of the age mismatch and propose that $\Delta_{\rm Age}$ indicates the time a young star remains bound to its parental cloud before moving away from its siblings. In this framework, the dynamical traceback "clock" starts when a stellar cluster or association begins to expand after expelling most of the gas, while the isochronal "clock" starts earlier when most stars form. The difference between these two age-dating techniques is a powerful tool to constraint evolutionary models, as isochronal ages cannot be younger than dynamical traceback ages. Measuring the $\Delta_{\rm Age}$ accurately and understanding its variations across different environments will provide further information on the impact of local conditions and stellar feedback on the formation and dispersal of stellar clusters.

Department of Astrophysics, Research Network Data Science
External organisation(s)
Centro de Astrobiología (CSIC-INTA), Ludwig-Maximilians-Universität München, Max-Planck-Institut für extraterrestrische Physik, Excellence Cluster ORIGINS, Harvard University
Nature Astronomy
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
103004 Astrophysics
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