Pleiades distances
Posted: 16.06.2006, 22:56
Does the stars.dat file take into account the systematic error in the Hipparcos measurements of the Pleiades distances or not?
The current version of stars.dat contains exactly the information provided in the Hipparcos database. Modified values are provided in STC catalog files, primarily in revised.stc. I think some corrections may be in nearstars.stc.
Although the parallaxes of maybe 3 or 4 stars in the Pleiades have been measured by other projects, most of them have not.
Has ESA published anything about what might have caused the systematic error? Whatever it was, I'm sure it would have affected more than just the Pleiades. At least two other clusters are believed to have similar but smaller errors.
See astro-ph/9803233
Title: The Problem of Hipparcos Distances to Open Clusters: I. Constraints from Multicolor Main Sequence Fitting
Authors: Marc H. Pinsonneault, John Stauffer, David R. Soderblom, Jeremy King, Robert B. Hanson
The abstract is available at http://arxiv.org/abs/astro-ph/9803233
It discusses the Hyades, Pleiades, Alpha Per, Praesepe, and Coma Ber cluster distances.
Hyades & Alpha Per are in agreement, Praesepe and Coma Ber may be in conflict, Pleiades disagrees by more than 3 sigma.