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Inaccuracies in the spectral classification of stars from the Tycho-2 Spectral Type Catalogue
We compare the spectroscopic and trigonometric parallaxes of commonstars from the Tycho-2 Spectral Type and Hipparcos Catalogues. Thiscomparison has revealed that the distance estimations for theoverwhelming majority of stars by both methods yield very similarresults. However, there is a small fraction of stars for which thedistance estimates differ significantly. It is these stars that are thesubject of our study. We have been able to find the causes of thesedifferences.
| Near-Infrared Spectra of Centaurs and Kuiper Belt Objects
We present here an extensive survey of near-infrared (NIR) spectra ofKuiper belt objects (KBOs) and Centaurs taken with the Keck I Telescope.We find that most spectra in our sample are well characterized by acombination of water ice and a featureless continuum. A comparativeanalysis reveals that the NIR spectral properties have littlecorrelation to the visible colors or albedo, with the exception of thefragment KBOs produced from the giant impact on 2003 EL61. The resultssuggest that the surface composition of KBOs is heterogeneous, thoughthe exposure of water ice may be controlled by geophysical processes.The Centaurs also display diverse spectral properties, but the source ofthe variability remains unclear. The results for both the KBOs and theCentaurs point to inherent heterogeneity in either the processes actingon these objects or materials from which they formed.
| Photoelectric measurements of lunar occultations. VIII
Photoelectric timings are reported for 276 lunar occultation eventswhich were observed between March 1975 and February 1976. The timings(in UTC) are based on Loran G equipment of a lunar laser-ranging groupor on WWV signals. Angular diameters are determined for HR 5301, HD176124, Chi-1-Orionis, and HR 601. Twenty cases of possible or actualdouble stars, including Beta Capricorni, are noted along with oneprobable triple system (51 Piscium). Several technical and computationaldifficulties encountered in this program are discussed.
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Membre dels grups següents:
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Dades d'Observació i Astrometria
| Constel·lació: | Libra |
| Ascensió Recta: | 14h51m10.21s |
| Declinació: | -18°55'08.1" |
| Magnitud Aparent: | 8.254 |
| Distancia: | 274.725 parsecs |
| Moviment propi RA: | 2.1 |
| Moviment propi Dec: | -60.9 |
| B-T magnitude: | 9.452 |
| V-T magnitude: | 8.353 |
Catàlegs i designacions:
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