Testing substellar models with dynamical mass measurements

T. J. Dupuy, M. C. Liu, M. J. Ireland

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

2 Citations (Scopus)
21 Downloads (Pure)


We have been using Keck laser guide star adaptive optics to monitor the orbits of ultracool binaries, providing dynamical masses at lower luminosities and temperatures than previously available and enabling strong tests of theoretical models. We have identified three specific problems with theory: (1) We find that model color-magnitude diagrams cannot be reliably used to infer masses as they do not accurately reproduce the colors of ultracool dwarfs of known mass. (2) Effective temperatures inferred from evolutionary model radii are typically inconsistent with temperatures derived from fitting atmospheric models to observed spectra by 100-300K. (3) For the only known pair of field brown dwarfs with a precise mass (3%) and age determination (≈25%), the measured luminosities are ∼2-3× higher than predicted by model cooling rates (i.e., masses inferred from Lbol and age are 20-30% larger than measured). To make progress in understanding the observed discrepancies, more mass measurements spanning a wide range of luminosity, temperature, and age are needed, along with more accurate age determinations (e.g., via asteroseismology) for primary stars with brown dwarf binary companions. Also, resolved optical and infrared spectroscopy are needed to measure lithium depletion and to characterize the atmospheres of binary components in order to better assess model deficiencies.

Original languageEnglish
Title of host publicationResearch, science and technology of brown dwarfs and exoplanets
Subtitle of host publicationproceedings of an international conference held in Shanghai on occasion of a total eclipse of the Sun
EditorsE. L. Martin, J. Ge, W. Lin
Place of PublicationLes Ullis, France
PublisherEDP Sciences
Number of pages7
ISBN (Electronic)9782759806645
Publication statusPublished - 2011
Externally publishedYes
EventInternational Conference Held in Shangai on Occasion of a Total Eclipse of the Sun - Shanghai, China
Duration: 20 Jul 200924 Jul 2009

Publication series

NameEPJ Web of Conferences
PublisherEDP Sciences
ISSN (Electronic)2100-014X


OtherInternational Conference Held in Shangai on Occasion of a Total Eclipse of the Sun

Bibliographical note

Copyright the Author(s) 2011. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


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