Tracing the Origin of Moving Groups. III. Detecting Moving Groups in The LAMOST DR7

TL;DR

This study analyzes the moving groups in the solar neighborhood using LAMOST DR7 data, detecting multiple groups and a new candidate, and suggests their origin is linked to resonant effects from the Milky Way's bar or spiral arms.

Contribution

It introduces a new detection of moving groups in LAMOST DR7 data and provides evidence supporting their origin from Galactic resonant mechanisms.

Findings

Five moving groups detected along with a new candidate.

Moving groups are spaced by 15-25 km/s in velocity.

Origin likely due to resonant effects from Galactic bar or spiral arms.

Abstract

We revisit the moving groups (MGs) in the solar neighborhood with a sample of 91969 nearby stars constructed from LAMOST DR7. Using the wavelet technique and Monte Carlo simulations, five MGs together with a new candidate located at $V \simeq$ -130 km s$^{-1}$ are detected simultaneously in $V-\sqrt{U^2+2V^2}$ space. Taking into account the other known MGs, we conclude that MGs in the Galactic disk are spaced by approximately 15 $\sim$ 25 km s$^{-1}$ along $V$ velocity. The origin of detected MGs is analysed through the distributions of [Fe/H]$-$[Mg/Fe] and ages. Our results support attributing the origin to the continuous resonant mechanisms probably induced by the bar or spiral arms of the Milky Way.