2026A&A...705A.108H -
Astronomy and Astrophysics, volume 705A108 (2026/1-1)
The velocity field of the Scorpius-Centaurus OB association I. Method and general properties.
HUTSCHENREUTER S., ALVES J., POSCH L., GROSSSCHEDL J., PIECKA M., MIRET-ROIG N., RATZENBOCK S. and SWIGGUM C.
Abstract (from CDS):
We present a nonparametric reconstruction of the three-dimensional velocity field of the Scorpius-Centaurus OB association (Sco-Cen). Using Gaia DR3 astrometry and radial velocities, we inferred the velocity field using information field theory on a 70 × 70 × 50 grid at a 3 pc resolution. Our model suggests the existence of a primary stellar velocity field with a secondary field that accounts for an additional young kinematic component in Upper Scorpius and Lupus. We find clear tracers of a feedback-driven expansion of the association, while Galactic rotation appears to play a subordinate role. The results confirm the existence of cluster chains and reveal coherent large-scale expansion with characteristic speeds of 1-2 km s–1 and local maxima of about 10 km s–1. Power spectra indicate an excess of small-scale structure and slopes shallower than Kolmogorov, consistent with energy injection from stellar feedback. Maps of the divergence reveal net positive values, implying an approximate dispersal timescale of 10-15 Myr. A comparison with molecular gas in Lupus and Ophiuchus shows broadly consistent patterns but systematic velocity offsets of several km s–1, suggesting partial decoupling for optically visible young stars and gas. The framework presented provides a physically motivated description of the Sco-Cen velocity field and a basis for quantifying the dynamical state and feedback history of OB associations in the local Galaxy.
Abstract Copyright:
© The Authors 2026
Journal keyword(s):
stars: kinematics and dynamics - ISM: kinematics and dynamics - Galaxy: kinematics and dynamics - open clusters and associations: general - solar neighborhood - open clusters and associations: individual: Scorpius-Centaurus
Simbad objects:
46
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