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HD 7774


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ICCD Speckle Observations of Binary Stars.XV.An Investigation of Lunar Occultation Systems
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....112.2260M&db_key=AST

UBV Photoelectric Observations of UV Piscium
Not Available

The 1986 Light Curves of UV Piscium
Not Available

Light and colour curve observations and analysis of the short period eclipsing binary system UV PSC
In the present work B and V light curves and the (B-V)-color curve ofthe short period (RS CVn type) binary system UV Psc are presented andanalyzed, and absolute information from the available data are derived.Chi-squared minimization procedures were utilized to a large extent infitting light and color curves. The solutions show the binary to be at adistance of about 90 pc with two detached components which are close tothe main sequence (G2 and K0). The inclination of the orbit is close to90 deg. Photometric irregularities present in the light curve arebriefly considered in relation to current ideas on RS CVn systems, andthe color information indicates that a locally hotter (rather thancooler) region is responsible for the irregularities.

UV Psc - a Short Period RS CVn Star
Not Available

Photoelectric observations of lunar occultations. X
Photoelectric occulation results for 461 events observed during 15months are reported. They include 77 reappearances, 4 determinations ofangular diameter, 38 analyses of double or multiple stars including twopreviously unknown bright stars, and 8 previously known bright double ormultiple stars.

On the problem of cohabitation between AM and delta-Scuti or 'normal' A stars - A unified theory
A previous interpretation (Baglin, 1972) of the occurrence of deltaScuti variables and Am stars in the same region of the H-R diagram foundan order of magnitude of the maximum rotational velocity that allows thestars to appear as Am. These stars are observed as nonpulsating stars asa consequence of the downward diffusion of helium. For higher rotationalvelocity, the turbulence in the external layers, due to the shearinstability of the meridional circulation, ensures a homogeneouschemical composition. It does not allow the diffusion processes to actefficiently and preserves the ability of the He ionization zone toenergize the pulsations, with the star appearing as a delta Scutivariable. This paper takes an alternate approach, assuming the rotationinduced by the meridional circulation to be time dependent and derivingReynolds and Richardson numbers for this differential rotation. It isshown, among other things, that the differential rotation maintains itsstability even if its Reynolds number is supercritical, as long as thedensity stratification is able to stabilize any perturbation accordingto the Richardson criterion.

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Observation and Astrometry data

Constellation:Poissons
Right ascension:01h17m34.47s
Declination:+07°09'00.3"
Apparent magnitude:9.373
Proper motion RA:26.2
Proper motion Dec:14.9
B-T magnitude:10.276
V-T magnitude:9.448

Catalogs and designations:
Proper Names
HD 1989HD 7774
TYCHO-2 2000TYC 26-271-1
USNO-A2.0USNO-A2 0900-00303554
HIPHIP 6038

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