LAMOST 1: A Disrupted Satellite in the Constellation Draco

TL;DR

This paper reports the discovery of a disrupted stellar satellite in Draco using LAMOST data, revealing a streaming group with specific metallicity, mass, and orbital characteristics, suggesting a globular cluster origin.

Contribution

First identification of a disrupted satellite in Draco with detailed spectroscopic analysis and orbital properties, indicating a globular cluster progenitor.

Findings

Identified a comoving stellar group in Draco at 2.6 kpc from the Sun.

The group has a metallicity of -0.64 dex and a mass of about 2.1E4 solar masses.

The system's properties suggest a globular cluster origin.

Abstract

Using LAMOST spectroscopic data, we find a strong signal of a comoving group of stars in the constellation of Draco. The group, observed near the apocenter of its orbit, is 2.6 kpc from the Sun with a metallicity of -0.64 dex. The system is observed as a streaming population of unknown provenance with mass of about 2.1E4 solar masses and an absolute V band magnitude of about -3.6. Its high metallicity, diffuse physical structure, and eccentric orbit may indicate that the progenitor satellite was a globular cluster rather than a dwarf galaxy or an open cluster.