Kinematics of the System of Young Open Clusters based on Gaia DR3 Data
astro-ph.GA
Submitted: 2026-09-17
Updated: 2026-09-17
Comments: 11 pages, 6 figures, Accepted to Astrophysical Bulletin
Code: https://github.com/elsid/newuoa-cpp
License: http://creativecommons.org/licenses/by/4.0/
The gist: We use a kinematical model including circular rotation of the Milky-Way disk incorporating effects produced by a spiral density wave with constant radial and vertical components of the velocity
Terminology
Abstract
We use a kinematical model including circular rotation of the Milky-Way disk incorporating effects produced by a spiral density wave with constant radial and vertical components of the velocity dispersion tensor and adopted solar Galactocentric distance R 0=8.277kpc (inferred by GRAVITY collaboration in 2022) to derive the velocity field parameters for a sample of 2384 open clusters from the Hunt and Reffert (2024) catalog having ages no greater than 100 Myr almost all of which reside at Galactoaxial distances between 5 and 14 kpc. We estimate the velocity-field parameters using maximum-likelyhood method and the affine-invariant variant of the Markov chain Monte-Carlo method proposed by Goodman and Weare (2010) with both methods yieilding almost identical parameter values. The inferred rotation curve, on the whole, is consistent with the results based on our kinematical analysis of a sample of Galactic masers. We find the linear rotation velocity at the solar distance to be V=242.3+/-1.1 km/s; it reaches its maximum V 244 km/s at Galactoaxial distance of about R g 7 kpc followed by a slow and smooth decline with V 227 km/s at R g=14 kpc. The inferred radial and vertical components of the velocity dispersion tensor are (sigma U 0, sigma W 0) (10.63+/-0.15, 4.56+/-0.15) km/s. We find the pitch angle and the phase of the Sun for a four-armed spiral pattern to be i-11.7+/-0.3 degrees and chi 0 138+/-5 degrees, respectively, and the amplitudes of radial and tangential perturbations, f R=-3.0+/-0.4 and f theta=-3.1+/-0.4 km/s, respectively.
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