Tycho-GaiaAstrometric Solution Parallaxes and Proper Motions for Five Galactic Globular Clusters
نویسندگان
چکیده
منابع مشابه
Accurate Internal Proper Motions of Globular Clusters
We have undertaken a long term program to measure high precision proper motions of nearby Galactic globular cluster (GC) stars using multi-epoch observations with the WFPC2 and the ACS cameras on-board the Hubble Space Telescope. The proper motions are used to study the internal cluster kinematics, and to obtain accurate cluster distances. In this paper, we also show how the proper motions of t...
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Context. A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming that the accuracies for nearly all stars brighter than magnitude Hp = 8 are improved, by up to a factor 4, compared to the original catalogue. As correlations between the underlying abscissa residuals have also been reduced by more than an order of magnitude to an insignificant lev...
متن کاملDistances and Absolute Ages of Galactic Globular Clusters from Hipparcos Parallaxes of Local Subdwarfs
High precision trigonometric parallaxes from the Hipparcos satellite and accurate metal abundances ((Fe/H], O/Fe], and /Fe]) from high resolution spectroscopy for about 30 local subdwarfs have been used to derive distances and ages for a carefully selected sample of nine globular clusters. We nd that Hipparcos parallaxes are smaller than the corresponding ground-based measurements leading, to a...
متن کاملDistances and Absolute Ages of Galactic Globular Clusters from Hipparcos Parallaxes of Local Subdwarfs *
High precision trigonometric parallaxes from the HIPPARCOS satellite and accurate metal abundances ([Fe/H], [O/Fe], and [α/Fe]) from high resolution spectroscopy for about 30 local subdwarfs have been used to derive distances and ages for a carefully selected sample of nine globular clusters. We find that HIPPARCOS parallaxes are smaller than the corresponding ground-based measurements leading,...
متن کاملHipparcos Parallaxes and Proper Motions of Cepheids and Their Implications *
A summary is given of an analysis of the Hippar-cos trigonometrical parallaxes and proper motions of classical Cepheids. It is possible for the first time to derive zero-points for the period-luminosity and period-luminosity-colour relations from paral-laxes alone, avoiding the problems of less direct methods. The results imply an increase of 8 to 10 percent in the extragalactic distance scale ...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2017
ISSN: 1538-4357
DOI: 10.3847/1538-4357/aa696f