Comparison of Gaia and Hipparcos parallaxes of close visual binary stars and the impact on determinations of their masses

Abstract

Precise measurement of the fundamental parameters of stellar systems, including mass and radius, depends critically on how well the stellar distances are known. Astrometry from space provides parallax measurements of unprecented accuracy, from which distances can be derived, initially from the Hipparcos mission, with a further refinement of that analysis provided by van Leeuwen in 2007. The publication of the Gaia DR2 catalogue promises a dramatic improvement in the available data. We have recalculated the dynamical masses of a sample of 1 700 close visual binary stars using Gaia DR2 and compared the results with masses derived from both the original and enhanced Hipparcos data. We show the van Leeuwen analysis yields results close to those of Gaia DR2, but the latter are significantly more accurate. We consider the impact of the Gaia DR2 parallaxes on our understanding of the sample of visual binaries.

Atmospheric and Fundamental Parameters of Eight Nearby Multiple Stars

“…Atmospheric and fundamental parameters of the components of BMSs have been estimated using Al-Wardat's method Al-Wardat et al (2021a). The method was successfully used to accurately analyze several BMSs (see, e.g., Al-Wardat 2002, 2009a, 2009bAl-Wardat et al 2014a, 2014b, 2016Masda et al 2016;Al-Wardat et al 2017;Masda et al 2018Masda et al , 2019aMasda et al , 2019bAl-Tawalbeh et al 2021;Yousef et al 2021;Al-Wardat et al 2021b).…”

“…These missions give one of the most fundamental pieces of information about a star or stellar system, the trigonometric parallax, from which a distance can be determined. Here, another potential benefit of studying binary stars is to study the precision of stellar parallaxes and to reveal any related systematic errors, such as in Gaia data release Gaia DR2 (Al-Wardat et al 2021a).…”

“…In this study, we estimate the atmospheric and fundamental parameters of the individual components of eight nearby multiple stellar systems, using Al-Wardat's method for analyzing binary and multiple stellar systems (BMSs; Al-Wardat 2002. Al-Wardatʼs method also gives important information about the accuracy of orbital parameters of multiple systems and also tests the accuracy of the parallax measurements (Al-Wardat et al 2021a). The reliability of Al-Wardat's method had been demonstrated in Al-Wardat et al (2021a), providing a useful consistency check for parallax measurements.…”

“…Al-Wardatʼs method also gives important information about the accuracy of orbital parameters of multiple systems and also tests the accuracy of the parallax measurements (Al-Wardat et al 2021a). The reliability of Al-Wardat's method had been demonstrated in Al-Wardat et al (2021a), providing a useful consistency check for parallax measurements. In addition, some of the parallaxes obtained by Hipparcos have been found to give more accurate masses than Gaia DR2 parallax measurements.…”

Physical and geometrical parameters of CVBS XIV: The two nearby systems HIP 19206 and HIP 84425

“…The preciseness of such studies is highly enhanced by the latest measurements of the distances to such systems, which were highly achieved by Gaia astrometric mission Collaboration et al(2018), Al-Wardat et al(2021).…”