Orbital and Physical Parameters of Visual Binary: WDS 17190-3459 ($\alpha 2000 = 17^\mathrm{h} 18^\mathrm{m} 56^\mathrm{s}$ and $\delta 2000 = - 34^\circ 59' 22"$)


Since the Bosscha Observatory was established in 1923 researches on visual binary stars played an important role in astronomical studies in Indonesia. The visual binary of WDS 17190-3459 = MLO 4AB = HD156384 = HIP84709 was extensively observed at our observatory and other observatories. This system has already passed periastron three times since observed in the end of year 1876. The observation data is more than enough to construct an orbit. By using Thiele-Innes method we computed the orbit, and physical parameters are determined by using mass-luminosity relation. The result is presented in the table. Orbital Parameters: $e = 0.578$, $P = 42.3$ years, $T = 1974.9$, $i = 132.7^\circ$,$\omega = 247.5^\circ$, $\Omega = 318.1^\circ$, $a = 1”.713$, $\mu = 8.51$ /years Physical Parameters: $p = 0”.134$, $M_ \mathrm{bol,1}=6.7$, $M_ \mathrm{bol,2}=7.4$, $M_ 1 = 0.6; M\odot$, $M_ 2 = 0.5; M\odot$, $q = 0.863$. At time being there are several new methods for determining the orbit; for example the method of Gauss done by Söderhjelm (1999) for calculating the orbit of the same stars WDS 17190-3459. Our results are relatively same.

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