Orbital Elements of visual binary stars with very short arcs: With application to double stars from the 1829 southern double star catalog of James Dunlop

Abstract

Binary double stars are those whose binding energies are less than zero. Obtaining binary star orbits from short arcs has been a long-standing problem in astrophysics. A method is presented and tested here, which addresses the problem by using space-based astrometry, photometry, and astrophysical data, together with historic measures, to generate and constrain a range of possible first-order Grade 5 orbits. After testing the method on an established binary star, we apply the method to eight double stars from the first published catalog of southern double stars, that of Dunlop (1829) and generate orbits for five. The mean orbital period is ∼81,000 years, and the mean semi-major axis is ∼76 ′′ with a typical uncertainty of the Orbital Elements of ∼37%. Their Orbital Elements and associated plots are also presented.