A Hipparcos study of the Hyades cluster

We use the Hipparcos and Tycho-2 proper motions, which have a larger relative precision than the Hipparcos trigonometric parallaxes, to derive 3 times more precise distance estimates, by assuming that all members share the same space motion. These so-called secular parallaxes are, as a set, statistically consistent with the Hipparcos parallaxes (Section 6).

Table A1 contains, for all 218 members identified by Perryman et al. (1998A&A...331...81P; see also Cat. <J/A+A/331/81>; see Sections 4.1 and 5.1), the trigonometric parallaxes, the Hipparcos and Tycho-2 secular parallaxes, their errors and goodness-of-fit parameters (Sections 2.2 and 5.4), as well as fundamental stellar parameters (Section 9) based on the Hipparcos secular parallaxes and the V-band magnitudes (field H5) and B-V colours (field H37) listed in the Hipparcos Catalogue (1997HIP...C......0E; Cat. <I/239>).