Astrophys. J., 548, 889-899 (2001/February-3)
Tomographic separation of composite spectra. VII. The physical properties of the massive triple system HD 135240 (δ Circini).
PENNY L.R., SEYLE D., GIES D.R., HARVIN J.A., BAGNUOLO W.G.Jr, THALLER M.L., FULLERTON A.W. and KAPER L.
Abstract (from CDS):
We present the results of a radial velocity study of the massive, double-lined, O binary HD 135240 based primarily on UV spectroscopy from the International Ultraviolet Explorer. Cross-correlation methods indicate the presence of a third stationary spectral line component which indicates that the system is a triple consisting of a central 3.9 day close binary with a distant companion. We measured radial velocities from the cross-correlation functions after removal of the third component, and we combined these with velocities obtained from Hα spectroscopy to reassess the orbital elements. We applied a Doppler tomography algorithm to reconstruct the individual UV spectra of all three stars, and we determine spectral classifications of O7 III-V, O9.5 V, and B0.5 V for the primary, secondary, and tertiary, respectively, using UV criteria defined by Penny, Gies, & Bagnuolo. We compare these reconstructed spectra to standard single-star spectra to find the UV flux ratios of the components (F2/F1=0.239±0.022, and F3/F1=0.179±0.021). Hipparcos photometry reveals that the central pair is an eclipsing binary, and we present the first model fit of the light curve from which we derive an orbital inclination, i=74°±3°. This analysis indicates that neither star is currently experiencing Roche lobe overflow. We place the individual components in the theoretical H-R diagram, and we show that the masses derived from the combined spectroscopic and photometric analysis (Mp/M☉=21.6±2.0 and Ms/M☉=12.4±1.0) are significantly lower than those computed from evolutionary tracks for single stars.
Stars: Binaries: Eclipsing - Stars: Binaries: Spectroscopic - Stars: Early-Type - Stars: Fundamental Parameters - stars: individual (HD 135240) - Ultraviolet: Stars
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