Three Moving Groups Detected in the LAMOST DR1 Archive

Abstract

We analyze the kinematics of thick disk and halo stars observed by the Large sky Area Multi-Object Fiber Spectroscopic Telescope. We have constructed a sample of 7,993 F, G and K nearby main-sequence stars (\textit{d} $<$ 2 kpc) with estimates of position (x, y, z) and space velocity ($U$, $V$, $W$) based on color and proper motion from the SDSS DR9 catalog. Three `phase-space overdensities' are identified in [\textit{V}, $\sqrt{U^2+2V^2}$] with significance levels of $\sigma$ $>$ 3. %[L${}_Z$, eccentricity], [L${}_Z$, L${}_{\perp }$], and [V${}_{az}$, V${}_{△}E$]. Two of them (Hyades-Pleiades stream, Arcturus-AF06 stream) have been identified previously. We also find evidence for a new stream (centered at \textit{V} $\sim$ -180 km s${}^{-1}$) in the halo. The formation mechanisms of these three streams are analyzed. Our results support the hypothesis the Arcturus-AF06 stream and the new stream originated from the debris of a disrupted satellite, while Hyades-Pleiades stream has a dynamical origin.

7 pages, 5 figures

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Cited by in corpus (4)

• Overview of the LAMOST survey in the first decade
• Estimation of distances to stars with stellar parameters from LAMOST
• Kinematic structures of the Solar neighbourhood revealed by Gaia DR1/TGAS and RAVE
• The substructures in the local stellar halo from Gaia and LAMOST