The nearest star of spectral type O3: a component of the multiple system HD 150136 |
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| Authors: | V S Niemela † R C Gamen †‡ |
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| Institution: | Facultad de Cs. Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina;Departamento de Física, Universidad de La Serena, Benavente 980, La Serena, Chile |
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| Abstract: | From radial velocities determined in high signal-to-noise digital spectra, we report the discovery that the brightest component of the binary system HD 150136 is of spectral type O3. We also present the first double-lined orbital solution for this binary. Our radial velocities confirm the previously published spectroscopic orbital period of 2.6 d. He ii absorptions appear double at quadratures, but single lines of N v and N iv visible in our spectra define a radial velocity orbit of higher semi-amplitude for the primary component than do the He ii lines. From our orbital analysis, we obtain minimum masses for the binary components of 27 and 18 M⊙ . The neutral He absorptions apparently do not follow the orbital motion of any of the binary components, thus they most probably arise in a third star in the system. |
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| Keywords: | binaries: spectroscopic stars: individual: HD 150136 |
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