The European Astrometry Satellite, Hipparcos
نویسندگان
چکیده
منابع مشابه
Photocentre displacement of minor planets: analysis of Hipparcos astrometry
We present a study of the phase effect (or photocentre offset) on the astrometry of minor planets. Analysis of the high precision Hipparcos observations of the largest asteroids shows the validity of the model. Minor planets Ceres, Pallas, Vesta and Iris show a brightness distribution close to the lunar scattering properties, while Juno and Hebe are found to be more uniformly bright objects. Fo...
متن کاملWhite dwarfs observed by the HIPPARCOS satellite
TheHIPPARCOSsatellite hasmeasured trigonometric parallaxes for 20 white dwarfs. With the exception of one each of the spectral types DZ, DC, DB, DQ, the majority are of spectral type DA. We compare the parallaxes with the most recent ground-based determinations. Froma spectroscopic analysis of new optical observations we determine atmospheric parameters Teff and log g. From the angular diameter...
متن کاملACCELERATION AND STOCHASTIC HIPPARCOS SOLUTIONS Based on observations made with the ESA Hipparcos satellite
The Hipparcos astrometric parameters were obtained through the merging of abscissae data obtained by FAST and NDAC Consortia. Using a different weighting scheme, close but different astrometric solutions may be obtained. The resulting influence on acceleration (G) and stochastic (X) solutions is discussed; these solutions are studied from the point of view of the possible signature of astrometr...
متن کاملConfirmation of Errors in Hipparcos Parallaxes from Hst/fgs Astrometry of the Pleiades
We present absolute trigonometric parallaxes and relative proper motions for three members of the Pleiades star cluster, obtained with HST’s Fine Guidance Sensor 1r, a white-light interferometer. We estimate spectral types and luminosity classes of the stars comprising the astrometric reference frame from R ≈ 2, 000 spectra, VJHK photometry, and reduced proper motions. From these we derive esti...
متن کاملPulsating and nonpulsating stars in Hyades observed by Hipparcos satellite
A study of the stars in the instability strip of Hyades cluster has been performed taking into account the new estimate of the stellar parallaxes. For taking advantage of the improved accuracy of the distances and hence absolute magnitudes it is necessary to separate the photometric effects of close companions, which appear quite common in Hyades. The δ Scuti stars, differently from nonpulsatin...
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ژورنال
عنوان ژورنال: Highlights of Astronomy
سال: 1980
ISSN: 1539-2996
DOI: 10.1017/s1539299600004731