منابع مشابه
Distances and absolute magnitudes from trigonometric parallaxes
In astrophysical applications, derived quantities like distances, absolute magnitudes and velocities are used instead of the observed quantities, such as parallaxes and proper motions. As the observed values are affected by random errors and selection effects, the estimates of the astrophysical quantities can be biased if a correct statistical treatment is not used. This paper presents and disc...
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Astrometry is one of the foundations of astrophysics. Accurate distances to stars and galaxies allow for significant tests of stellar evolution, galaxy formation and evolution and cosmology. NASA’s Space Interferometry Mission (SIM) will obtain extraordinary precision astrometry [1-10 μas positional accuracy] for ten to twenty thousand objects brighter than V=20 mag. In this paper we discuss a ...
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Abstract Alignment-free distance measures are generally less accurate but more efficient than traditional alignment-based metrics. In the context of genome sequence analysis, the efficiency gain is often so substantial that it outweights the loss in accuracy. However, a further disadvantage of alignment-free distances is that their relationship to evolutionary events such as substitutions is ge...
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,...
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ژورنال
عنوان ژورنال: Publications of the Astronomical Society of the Pacific
سال: 2015
ISSN: 0004-6280,1538-3873
DOI: 10.1086/683116