Enhanced Kinematics and Distribution Characteristics of Upper Scorpius and Ophiuchus Associations Based on Gaia DR3

Abstract

The kinematics within the solar vicinity have revealed interesting features relevant to both stellar and Galactic structures. This study examines three stellar associations in the Upper Scorpius and Ophiuchus regions, along with their sub-samples among Gaia DR3. The calculated kinematics and velocity ellipsoid characteristics, including the mean spatial velocity components (U, V, and W; km s⁻¹), yielding values of approximately (−5.84 ± 2.42, −16.14 ± 4.02, −7.31 ± 2.70; km s⁻¹). USC and Oph associations velocity dispersion within the ellipsoid (${\sigma }_i,\forall i=1,2,3$) was found to be (1.36 ± 0.02, 0.80 ± 0.01, 0.96 ± 0.01; km s⁻¹), their mean solar motion ($S_{\odot }$) was determined to be approximately 18.62 ± 4.32 km s⁻¹, convergent point coordinates ($A_o,D_o$) were (95.91 ± 0.09°, −44.42 ± 0.02°), and Oort's constants, yielding A = 17.80 ± 0.24 km s⁻¹ kpc⁻¹ and B = −9.61 ± 0.32 km s⁻¹ kpc⁻¹. Finally, the density distribution function per absolute magnitudes of USC and Oph associations is examined to obtain both luminosity and mass functions; their analysis revealed the absence of any peaks or dips as consistent with other recent studies.