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HD 191640


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Speckle Interferometry of New and Problem HIPPARCOS Binaries
The ESA Hipparcos satellite made measurements of over 12,000 doublestars and discovered 3406 new systems. In addition to these, 4706entries in the Hipparcos Catalogue correspond to double star solutionsthat did not provide the classical parameters of separation and positionangle (rho,theta) but were the so-called problem stars, flagged ``G,''``O,'' ``V,'' or ``X'' (field H59 of the main catalog). An additionalsubset of 6981 entries were treated as single objects but classified byHipparcos as ``suspected nonsingle'' (flag ``S'' in field H61), thusyielding a total of 11,687 ``problem stars.'' Of the many ground-basedtechniques for the study of double stars, probably the one with thegreatest potential for exploration of these new and problem Hipparcosbinaries is speckle interferometry. Results are presented from aninspection of 848 new and problem Hipparcos binaries, using botharchival and new speckle observations obtained with the USNO and CHARAspeckle cameras.

Speckle interferometry of HIPPARCOS link stars. II
A second list is presented of stars that have been tested for theirsuitability as astrometric links between the Hipparcos satellite and theSpace Telescope. A speckle interferometer and autocorrelator were used,first on the 1.9-m telescope of the Mt. Stromlo and Siding SpringObservatories, and then, after discarding 16 stars showing evidence of abinary nature, on the Anglo-Australian 3.9-m telescope. Results aregiven for 123 stars. Combining the present list with the 1984 list, itis estimated that 29 percent of the original selection of 'cleanlooking' stars (on sky survey prints) are expected to be multiple at theresolution of the 3.9-m telescope, 0.03-0.7 arcsec.

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Observation and Astrometry data

Constellation:やぎ座
Right ascension:20h11m26.91s
Declination:-15°51'54.6"
Apparent magnitude:10.574
Proper motion RA:6.3
Proper motion Dec:-24.7
B-T magnitude:11.048
V-T magnitude:10.614

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 191640
TYCHO-2 2000TYC 6315-919-1
USNO-A2.0USNO-A2 0675-35025172
HIPHIP 99491

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