We cross-correlate the Herbig & Bell and Hipparcos Catalogues in order to extract the results for young stellar objects (YSOs). We compare the distances of individual young stars and the distance of their presumably associated molecular clouds, taking into account post-Hipparcos distances to the relevant associations and using Hipparcos intermediate astrometric data to derive new parallaxes of ...

In this paper two methods, an area based matching and a so called dynamic line warping, for generating digital surface models (DSMs) from IKONOS image pairs are compared and their limitations and usability for the rapid generation of good DSMs are discussed. The new dynamic line warping method is based on techniques used in speech recognition for warping corresponding epipolar lines of the ster...

If the microlensing events now being detected toward the Large Magellanic Cloud (LMC) are due to lenses in the Milky Way halo, then the events should typically have asymmetries of order 1% due to parallax from the reflex motion of the Earth. By contrast, if the lenses are in the LMC, the parallax effects should be negligible. A ground-based search for such parallax asymmetries would therefore c...

Hipparcos trigonometrical parallaxes of Mira-type variables have been combined with ground-based angular diameter measurements to derive linear diameters. Of eight stars with ground-based data, six have diameters indicating overtone pulsation whilst two, both with periods over 400 day, are pulsating in the fundamental. Hipparcos parallaxes of 11 Miras have been combined with extensive infrared ...

Aims. This is the first paper in a series dedicated to investigating the kinematic properties of nearby associations of young stellar objects. Here we study the Taurus-Auriga association, with the primary objective of deriving kinematic parallaxes for individual members of this low-mass star-forming region. Methods. We took advantage of a recently published catalog of proper motions for pre-mai...

The spectroscopic parallaxes in the Hipparcos catalogue can be used to translate absolute stellar fluxes observed at Earth to the fluxes emerging at the stellar surface for nearby stars. The comparison of these fluxes with the predictions of theoretical model atmospheres allows us to determine the effective temperature and the metallicity of the stars. It is suggested that it is possible to stu...

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 ...