Identifying Accelerating Stars Based on Long-term Multi-epoch Data

Previous observational investigations have revealed that roughly 50% of binary systems have orbital periods over a century. Binary systems with such long periods typically have large angular distances between the component stars, hence called wide binaries. It is then difficult to derive their precise orbital parameters by using only high precision observational data collected in recent several decade years. In fact, even identifying them as non-single stars is sometimes a challenge. Combining recent high precision and some early low precision star catalogs, we compile a multi-epoch star catalogue. And, based on observational errors and a time factor, we develop a novel weighting scheme, with which the weights of early low precision observational data in our least-square fitting are reasonably increased. Based on the null hypothesis of uniform rectilinear motion, the chi-square significance test is applied to the stars in the multi-epoch star catalog. As a result, 2214 accelerating stars, of which 1565 are new, are identified as candidates for wide binary stars. Upon cross-matching with existing binary star catalogs, the result suggests that the detection methodology based on early star catalogs and developed in this study shows remarkable superiority in terms of the identification efficiency of wide binary star systems.