The Discovery of Hot Stars near the Galactic Center, Thermal Radio Filaments

Angela S. Cotera(1), Edwin F. Erickson(2), Sean W. J. Colgan(2,3),, Janet P. Simpson (2,4), David A. Allen(5,6), and Michael G. Burton(7)

(1) Stanford University, Applied Physics Department, Stanford, CA 94305 (2) NASA/Ames Research Center, MS 245-6, Moffett Field, CA 94035 (3) The SETI Institute (4) University of California, Berkeley (5) Deceased, 1994 July 26, depriving us prematurely of a versatile and capable astronomer and a good friend to many of us. --Editor (6) Anglo-Australian Observatory (7) University of New South Wales, School of Physics, P.O. Box 1, 2033 Kensington, NSW, Australia

Paper: [Ap.J. in press]



We report the discovery of a highly unusual cluster of stars at G0.121+0.017 near the Arched (thermal) Filaments, ~10' northeast of the Galactic Center. H (1.65 \micron\ ) and K^\prime(2.1 \micron\ ) images are used to estimate a distance to the cluster consistent with a Galactic Center location. K^\prime band spectroscopy reveals that the cluster contains 13 stars with Br\gagt;~mma (2.166 \mum) emission, 12 of these stars also have \hei\ (2.112/3 \mum) emission, and 2 show fainter \heii\ (2.189 \mum) emission. Based on a spectral comparison with optically classified stars, we suggest the new emission stars are late WN stars. If the classification is correct, the cluster contains ~14% of all known galactic WN stars. Observations of emission line stars near G0.15--0.05, the \lq Pistol \rq, are also presented. There are four stars near the Pistol which contain emission lines. Three of these stars differ spectroscopically from the stars in the new cluster; one has a spectrum similar to the new cluster stars. Together with the cluster stars, these newly discovered hot young stars provide evidence for recent star formation and the stellar ionization of the thermal radio emission regions in the vicinity of the Galactic Center.

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