The nearest star of spectral type O3: a component of the multiple system HD 150136

NIEMELA, V. S.; GAMEN, R. C.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Año: 2005 vol. 356 p. 974 - 978

0035-8711

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. HeII absorptions appear double at quadratures, but single lines of NV and NIV visible in our spectra define a radial velocity orbit of higher semi-amplitude for the primary component than do the HeII lines. From our orbital analysis, we obtain minimum masses for the binary components of 27 and 18 Msolar. 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.