TY - JOUR
T1 - The peculiar population of hot stars at the galactic center
AU - Tamblyn, Peter
AU - Rieke, G. H.
AU - Hanson, Margaret Murray
AU - Close, L. M.
AU - McCarthy, D. W.
AU - Rieke, M. J.
N1 - Funding Information:
This study was supported in part by the National Science Council of the Republic of China under contract numbers NSC 96-2520-S-024-004-MY3 and NSC 97-2631-S-024-002.
PY - 1996
Y1 - 1996
N2 - Brγ and He I 2.058 μm images of the Galactic center reveal that most of the Brγ emission is associated with interstellar gas but that the He I is largely concentrated on individual, luminous stars that therefore must be hot. High-resolution spectra of these stars, emphasizing He I 2.058 μm through Brγ 2.166 μm, are compared with spectra of 98 hot, luminous stars from the literature and new spectra of 43 luminous galactic emission-line stars including late nitrogen sequence Wolf-Rayet, luminous blue variable (LBV), Oe, Of, and ON supergiant stars. Combining our data with other observations from the literature, the He I sources in the central parsec include approximately five Ofpe/WN stars and one late-WC star. The inferred luminosity and detection of Mg II emission lines in the spectrum of IRS 16NE make it a likely LBV candidate. However, we find six stars with line widths < 500 km s-1 which defy easy classification, even from the extensive library of comparison spectra we have compiled. Considering the ultraviolet constraints of Serabyn & Lacy and Shields & Ferland and the large number of peculiar hot stars, either we see this stellar population at a very distinctive moment in its evolution, or the conditions of formation or the evolution of the stars must be significantly altered by the environment in the central parsec.
AB - Brγ and He I 2.058 μm images of the Galactic center reveal that most of the Brγ emission is associated with interstellar gas but that the He I is largely concentrated on individual, luminous stars that therefore must be hot. High-resolution spectra of these stars, emphasizing He I 2.058 μm through Brγ 2.166 μm, are compared with spectra of 98 hot, luminous stars from the literature and new spectra of 43 luminous galactic emission-line stars including late nitrogen sequence Wolf-Rayet, luminous blue variable (LBV), Oe, Of, and ON supergiant stars. Combining our data with other observations from the literature, the He I sources in the central parsec include approximately five Ofpe/WN stars and one late-WC star. The inferred luminosity and detection of Mg II emission lines in the spectrum of IRS 16NE make it a likely LBV candidate. However, we find six stars with line widths < 500 km s-1 which defy easy classification, even from the extensive library of comparison spectra we have compiled. Considering the ultraviolet constraints of Serabyn & Lacy and Shields & Ferland and the large number of peculiar hot stars, either we see this stellar population at a very distinctive moment in its evolution, or the conditions of formation or the evolution of the stars must be significantly altered by the environment in the central parsec.
KW - Galaxy: Center
KW - Infrared: Stars
KW - Stars: Emission-line, be
KW - Stars: Wolf-rayet supergiants
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U2 - 10.1086/176641
DO - 10.1086/176641
M3 - Article
AN - SCOPUS:21844491856
SN - 0004-637X
VL - 456
SP - 206
EP - 216
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1 PART I
ER -