Orbit, Dynamical Mass, and MK Type of Visual Binary WOR 2

Abstract

On the basis of new speckle measurements with the 6 m telescope of the Special Astrophysical Observatory (Russia) and Hipparcos astrometry, an improved orbital solution with a period of P=24.1 yr for the visual binary WOR 2 is obtained. The dynamical mass of the system is 1.40+/-0.25 M_solar. Differential photometry (Δm=0.55 mag) allowed us to estimate the luminosity of individual components (M=+8.0 and +8.6 mag), which in turn led to individual masses of 0.65 and 0.61 M_solar, in good agreement with the systemic mass. The slit spectra obtained with the 2.6 m telescope of the Byurakan Astrophysical Observatory (Armenia) show that in the combined light WOR 2 is a K6 dwarf, whereas individually the components according to their luminosities are likely to be K6-K7 and M0 dwarfs. The equivalent width of the Hα absorption line (0.9 Å) is concordant with previous data, indicating the overall stability of this system.