AAS 203rd Meeting, January 2004
Session 25 Young Stars and Clusters
Oral, Monday, January 5, 2004, 10:00-11:30am, Centennial IV

[25.01] Infrared Observations of LBV 1806-20 and Nearby Cluster Stars

S. Eikenberry (University of Florida), K. Matthews (California Institute of Technology), J. L. LaVine (University of Florida), M. Garske (Cornell Univ., Northwest Nazarene Univ.), D. Hu, M.A. Jackson (Cornell University), S.G. Patel (Univ. of Florida, Cornell Univ.), D.J. Barry, M.R. Colonno, J.R. Houck (Cornell University), J.C. Wilson (Univ. of Virginia, Cornell Univ.), S. Corbel (Univ. Paris VII, CEA Saclay), J.D. Smith (Steward Observatory)

We report near-infrared photometry, spectroscopy, and speckle imaging of the hot, luminous star we identify as LBV 1806-20. We also present photometry and spectroscopy of 3 nearby stars, which are members of the same star cluster containing LBV 1806-20 and SGR 1806-20. The spectroscopy and photometry show that LBV 1806-20 is similar in many respects to the luminous Pistol Star'', albeit with some important differences. They also provide estimates of the effective temperature and reddening of LBV 1806-20, and confirm distance estimates, leading to an estimate for the luminosity of this star of > 5 \times 106 \ L\odot. The nearby cluster stars have spectral types and inferred absolute magnitudes which confirm the distance (and thus luminosity) estimate for LBV 1806-20. Furthermore, based on very high angular-resolution speckle images, we determine that LBV 1806-20 is not a cluster of stars, but is rather a single star or binary system. Simple arguments based on the Eddington luminosity lead to an estimate of the total mass of LBV 1806-20 (single or binary) exceeding 200 \ M\odot. We discuss the possible uncertainties in these results, and their implications for the star formation history of this cluster.

Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.