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Red giant clump in the Tycho-2 catalogue

Gontcharov, G. A.

The Tycho-2 proper motions and Tycho-2 and 2MASS photometry are used to select 97348 red giant clump (RGC) stars. The interstellar extinction and photometric distance are calculated for each of the stars. The selected stars are shown to form a selection-unbiased sample of RGC stars within about 350 pc of the Sun with the addition of more distant s…

Dynamical study of wide pairs of stars based on data from the WDS catalog

Kiselev, A. A.; Kiyaeva, O. V.; Izmailov, I. S.

Using the method of apparent motion parameters, we have studied the relative motion of the components in 561 pairs of wide ( ρ > 2″) and relatively nearby (Hipparcos parallaxes > 0.01″) visual double stars based on data from the WDS catalog. The minimum masses of the double stars have been calculated at given parallaxes. We have identified 3…

OB stars in the Tycho-2 and 2MASS catalogues

Gontcharov, G. A.

The Tycho-2 proper motions and five-band Tycho-2 and 2MASS photometry for approximately 2.5 million common stars have been used to select OB stars and to determine the extinction and photometric distance for each of them. We have selected 37 485 stars and calculated their reddenings based on their positions in the two-color V _T - H, J-…

Inaccuracies in the spectral classification of stars from the Tycho-2 Spectral Type Catalogue

Tsvetkov, A. S.; Popov, A. V.; Smirnov, A. A.

We compare the spectroscopic and trigonometric parallaxes of common stars from the Tycho-2 Spectral Type and Hipparcos Catalogues. This comparison has revealed that the distance estimations for the overwhelming majority of stars by both methods yield very similar results. However, there is a small fraction of stars for which the distance estimates…

Orientation of the hipparcos frame with respect to the reference frames of the DE403/LE403 and DE405/LE405 ephemerides based on asteroid observations

Chernetenko, Yu. A.

Highly accurate observations of 116 asteroids are used to determine the orientation of the Hipparcos frame with respect to the reference frames of the DE403/LE403 and DE405/LE405 majorplanet ephemerides. These observations include the photographic observations of 15 asteroids obtained as part of the programs for observing selected asteroids and re…