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Systematic error of the Gaia DR1 TGAS parallaxes from data for the red giant clump
Gontcharov, G. A.
Based on the Gaia DR1 TGAS parallaxes and photometry from the Tycho-2, Gaia, 2MASS, andWISE catalogues, we have produced a sample of 100 000 clump red giants within 800 pc of the Sun. The systematic variations of the mode of their absolute magnitude as a function of the distance, magnitude, and other parameters have been analyzed. We show that the…
Properties of the Tycho-2 catalogue from Gaia data release
Tsvetkov, A. S.; Vityazev, V. V.; Petrov, S. D. +2 more
Based on the measurements performed in the first 14 months of Gaia operation, we have solved the problem of obtaining the systematic differences between the stellar positions and proper motions of the TGAS (Tycho-Gaia Astrometric Solution) and Tycho-2 catalogues. By dividing the common stars from the TGAS and Tycho-2 catalogues into three G-magnit…
Spectroscopic studies of yellow supergiants in the Cepheid instability strip
Usenko, I. A.
High-resolution spectra of nine yellow nonvariable supergiants (NVSs) located within the canonical Cepheid instability strip from Sandage and Tammann (1969) ( α Aqr, ɛ Leo, µ Per, ω Gem, BD+60 2532, HD 172365, HD 187299, HD 190113, and HD 200102) were taken with the 1-m Zeiss and 6-m BTA telescopes at the Special Astrophysical Observatory of…