On the age, spectral type, orbit, and comparison to evolutionary models of AB Dor C

L. M. Close, E. L. Nielsen, J. C. Guirado, B. A. Biller, R. Lenzen, W. Brandner, M. Hartung, C. Lidman

Research output: Contribution to journalReview articlepeer-review


We expand upon the results of Close et al. 2005 regarding the young, low-mass object AB Dor C and its role as a calibration point for theoretical tracks. We argue for a new 70±30 Myr age estimate and present two additional detections of C with the Simultaneous Differential Imaging (SDI) camera. Our improved analysis (Nielsen et al. 2005) confirms our spectral type of M8 (±1) and mass of 0.090 ±0.003 Msun for AB Dor C. However, Luhman & Potter (2006) argue for a hotter spectral type (M6±1). Here we adopt the consistent spectral range of M7±1 in this paper as a final spectral type. Plotting AB Dor C (and all other young (<0.12 Myr), low-mass (0.3-0.05Msun) objects with accurate dynamical masses) on the HR diagram suggests a trend where current evolutionary models tend to over-predict the temperature (or under-predict the mass) for young low-mass stars and high-mass brown dwarfs. With our uncertainties, there is a ∼90% chance that the mass of AB Dor C is underestimated by the DUSTY tracks in the HR diagram.

Original languageEnglish (US)
Pages (from-to)11-18
Number of pages8
JournalProceedings of the International Astronomical Union
Issue numberC200
StatePublished - 2005


  • Brown Dwarfs
  • Infrared: Stars
  • Stars: Formation
  • Stars: Individual: AB Dor
  • Stars: Low-Mass
  • Stars: Pre-Main-Sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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