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Multiperiodicities from the Hipparcos epoch photometry and possible pulsation in early A-type stars
A selection criterion based on the relative strength of the largestpeaks in the amplitude spectra, and an information criterion are used incombination to search for multiperiodicities in Hipparcos epochphotometry. The method is applied to all stars which have beenclassified as variable in the Hipparcos catalogue: periodic, unsolvedand microvariables. Results are assessed critically: although there aremany problems arising from aliasing, there are also a number ofinteresting frequency combinations which deserve further investigation.One such result is the possible occurrence of multiple periods of theorder of a day in a few early A-type stars. The Hipparcos catalogue alsocontains a number of these stars with single periodicities: such starswith no obvious variability classifications are listed, and informationabout their properties (e.g., radial velocity variations) discussed.These stars may constitute a new class of pulsators.
| The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
| Photoelectric photometry of stars in the Vilnius system in Kapteyn areas SA 2, 4 and 6
Photoelectric photometry in the Vilnius system of 114 standard stars inKapteyn areas SA 2, 4, and 6 is presented with mean square errors of thearithmetic mean +/- 0.005 mag. Photometrically determined spectral typesand luminosity classes of the stars are also presented.
| Photoelectric Photometry of Stars in Kapteyn Area SA:6 in the Vilnius Photometric System
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Membre dels grups següents:
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Dades d'Observació i Astrometria
| Constel·lació: | Ursa Minor |
| Ascensió Recta: | 16h04m15.65s |
| Declinació: | +75°47'11.0" |
| Magnitud Aparent: | 7.907 |
| Distancia: | 1886.792 parsecs |
| Moviment propi RA: | 0.3 |
| Moviment propi Dec: | -38.3 |
| B-T magnitude: | 9.937 |
| V-T magnitude: | 8.075 |
Catàlegs i designacions:
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