Fundamental Parameters of 4 Massive Eclipsing Binaries in Westerlund 1

Home , Contact binary, Luminous blue variable

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o Binary P(days) M1(M⊙) M2(M⊙) R1(R⊙) R2(R⊙) logg1 logg2 eccentr Incl( ) Wddeb 4.447 9.62 13.84 5.47 6.22 3.94 3.99 0.177 84.46 Wd36 3.182 10.75 12.51 9.45 10.15 3.52 3.52 0(fixed) 72.72 WR77o 3.520 49.67 19.87 18.06 11.81 3.62 3.59 0(fixed) 58.53 Wd13 9.267 29.91 23.86 26.88 24.08 3.05 3.05 0(fixed) 55.08 Table 1: Fundamental Parameters of Eclipsing Binaries in Wd1 Wd13: is a semi-detached, double-lined spectroscopic binary (B0.5Ia+ and OB types, Negueruela et al. 2010) in a circular orbit. We can see both absorption and emission lines in its spectra. Wd36: is an overcontact, double-lined spectroscopic binary system (OB-type) in a circular orbit (see Fig. 1). WR77o: is probably a double contact binary system in an almost circular orbit. It is a single lined spectroscopic binary and thus it is difficult to determine the parameters of its component stars. The spectroscopic visible star is a Wolf-Rayet star of spectral type WN6-7 (Negueruela & Clark 2005), given the large line widths of 2000 km s−1. Wddeb: is a detached, double-lined spectroscopic binary system (OB-type) with an eccentricity of almost 0.2.

Figure 1: Phased I, R light curves and radial velocity curve of Wd36, respectively. References Bonanos, A.Z. 2007, AJ, 133, 2696 Lanz, T. & Hubeny, I. 2003, ApJS, 146, 417 Muno, M. P., Clark, J. S., Crowther, P. A. et al. 2006, ApJ, 636, 41 Negueruela, I. & Clark, J. S. 2005, A&A, 436, 541 Negueruela, I., Clark, J. S. & Ritchie, B. W. 2010, A&A, 516, 78 Prsa, A. & Zwitter, T. 2005, ApJ, 628, 426 Westerlund, B. 1961, AJ, 66, 57