TY - JOUR

T1 - Kinematics of Stars from the TGAS (Gaia DR1) Catalogue

AU - Vityazev, V. V.

AU - Popov, A. V.

AU - Tsvetkov, A. S.

AU - Petrov, S. D.

AU - Trofimov, D. A.

AU - Kiyaev, V. I.

N1 - Vityazev, V.V., Popov, A.V., Tsvetkov, A.S. et al. Kinematics of Stars from the TGAS (Gaia DR1) Catalogue. Astron. Lett. 44, 236–247 (2018). https://doi.org/10.1134/S1063773718030040

PY - 2018

Y1 - 2018

N2 - Based on the stellar proper motions of the TGAS (Gaia DR1) catalogue, we have analyzed the velocity field of main-sequence stars and red giants from the TGAS catalogue with heliocentric distances up to 1.5 kpc. We have obtained four variants of kinematic parameters corresponding to different methods of calculating the distances from the parallaxes of stars measured with large relative errors. We have established that within the Ogorodnikov–Milne model changing the variant of distances affects significantly only the solar velocity components relative to the chosen centroid of stars, provided that the solution is obtained in narrow ranges of distances (0.1 kpc). The estimates of all the remaining kinematic parameters change little. This allows the Oort coefficients and related Galactic rotation parameters as well as all the remaining Ogorodnikov–Milne model parameters (except for the solar terms) to be reliably estimated irrespective of the parallax measurement accuracy. The main results obtained from main-sequence stars in the range of distances from 0.1 to 1.5 kpc are: A = 16.29 ± 0.06 km s−1 kpc−1, B = −11.90 ± 0.05 km s−1 kpc−1, C = −2.99 ± 0.06 km s−1 kpc−1, K = −4.04 ± 0.16 km s−1 kpc−1, and the Galactic rotation period P = 217.41 ± 0.60 Myr. The analogous results obtained from red giants in the range from 0.2 to 1.6 kpc are: the Oort constants A = 13.32 ± 0.09 km s−1 kpc−1, B = −12.71 ± 0.06 km s−1 kpc−1, C = −2.04 ± 0.08 km s−1 kpc−1, K = −2.72 ± 0.19 km s−1 kpc−1, and the Galactic rotation period P = 236.03 ± 0.98 Myr. The Galactic rotation velocity gradient along the radius vector (the slope of the Galactic rotation curve) is −4.32 ± 0.08 km s−1 kpc−1 for main-sequence stars and −0.61 ± 0.11 km s−1 kpc−1 for red giants. This suggests that the Galactic rotation velocity determined from main-sequence stars decreases with increasing distance from the Galactic center faster than it does for red giants.

AB - Based on the stellar proper motions of the TGAS (Gaia DR1) catalogue, we have analyzed the velocity field of main-sequence stars and red giants from the TGAS catalogue with heliocentric distances up to 1.5 kpc. We have obtained four variants of kinematic parameters corresponding to different methods of calculating the distances from the parallaxes of stars measured with large relative errors. We have established that within the Ogorodnikov–Milne model changing the variant of distances affects significantly only the solar velocity components relative to the chosen centroid of stars, provided that the solution is obtained in narrow ranges of distances (0.1 kpc). The estimates of all the remaining kinematic parameters change little. This allows the Oort coefficients and related Galactic rotation parameters as well as all the remaining Ogorodnikov–Milne model parameters (except for the solar terms) to be reliably estimated irrespective of the parallax measurement accuracy. The main results obtained from main-sequence stars in the range of distances from 0.1 to 1.5 kpc are: A = 16.29 ± 0.06 km s−1 kpc−1, B = −11.90 ± 0.05 km s−1 kpc−1, C = −2.99 ± 0.06 km s−1 kpc−1, K = −4.04 ± 0.16 km s−1 kpc−1, and the Galactic rotation period P = 217.41 ± 0.60 Myr. The analogous results obtained from red giants in the range from 0.2 to 1.6 kpc are: the Oort constants A = 13.32 ± 0.09 km s−1 kpc−1, B = −12.71 ± 0.06 km s−1 kpc−1, C = −2.04 ± 0.08 km s−1 kpc−1, K = −2.72 ± 0.19 km s−1 kpc−1, and the Galactic rotation period P = 236.03 ± 0.98 Myr. The Galactic rotation velocity gradient along the radius vector (the slope of the Galactic rotation curve) is −4.32 ± 0.08 km s−1 kpc−1 for main-sequence stars and −0.61 ± 0.11 km s−1 kpc−1 for red giants. This suggests that the Galactic rotation velocity determined from main-sequence stars decreases with increasing distance from the Galactic center faster than it does for red giants.

KW - Gaia DR1

KW - Galactic kinematics

KW - TGAS

KW - proper motions

UR - http://www.scopus.com/inward/record.url?scp=85045414951&partnerID=8YFLogxK

U2 - 10.1134/S1063773718030040

DO - 10.1134/S1063773718030040

M3 - Article

VL - 44

SP - 236

EP - 247

JO - Astronomy Letters

JF - Astronomy Letters

SN - 1063-7737

IS - 4

ER -