Hokupa'a-gemini discovery of two ultracool companions to the young star HD 130948

D. Potter, E. L. Martín, M. C. Cushing, P. Baudoz, W. Brandner, O. Guyon, R. Neuhäuser

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99 Scopus citations


We report the discovery of two faint ultracool companions to the nearby (d ∼ 17.9 pc) young G2 V star HD 130948 (HR 5534, HIP 72567) using the Hokupa'a adaptive optics (AO) instrument mounted on the Gemini North 8 m telescope. Both objects have the same common proper motion as the primary star as seen over a 7 month baseline and have near-IR photometric colors that are consistent with an early L classification. Near-IR spectra taken with the NIRSPEC AO instrument on the Keck II telescope reveal K I lines, FeH, and H 2O band heads. Based on these spectra, we determine that both objects have a spectral type of dL2 with an uncertainty of two spectral subclasses. The position of the new companions on the H-R diagram in comparison with theoretical models is consistent with the young age of the primary star (<0.8 Gyr) estimated on the basis of X-ray activity, lithium abundance, and fast rotation. HD 130948B and C likely constitute a pair of young contracting brown dwarfs with an orbital period of about 10 yr and will yield dynamical masses for L dwarfs in the near future.

Original languageEnglish (US)
Pages (from-to)L133-L136
JournalAstrophysical Journal
Issue number2 II
StatePublished - Mar 10 2002


  • Binaries: close
  • Binaries: visual
  • Stars: evolution
  • Stars: fundamental parameters
  • Stars: imaging
  • Stars: low-mass, brown dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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