Discovery of a Metal-Poor Field Giant with a Globular Cluster Second-Generation Abundance Pattern

Abstract

We report on detection, from observations obtained with the APOGEE spectroscopic survey, of a metal-poor ([Fe/H] $=-1.3$ dex) field giant star with an extreme Mg-Al abundance ratio ([Mg/Fe] $=-0.31$ dex; [Al/Fe] $=1.49$ dex). Such low Mg/Al ratios are seen only among the second-generation population of globular clusters, and are not present among Galactic disk field stars. The light element abundances of this star, 2M16011638-1201525, suggest that it could have been born in a globular cluster. We explore several origin scenarios, in particular studying the orbit of the star to check the probability of it being kinematically related to known globular clusters. We performed simple orbital integrations assuming the estimated distance of 2M16011638-1201525 and the available six-dimensional phase-space coordinates of 63 globular clusters, looking for close encounters in the past with a minimum distance approach within the tidal radius of each cluster. We found a very low probability that 2M16011638-1201525 was ejected from most globular clusters; however, we note that the best progenitor candidate to host this star is globular cluster $\omega$ Centauri (NGC 5139). Our dynamical investigation demonstrates that 2M16011638-1201525 reaches a distance $|Z_{max}|<3$ kpc from the Galactic plane and a minimum and maximum approach to the Galactic center of $R_{min}<0.62$ kpc and $R_{max}<7.26$ kpc in an eccentric ($e\sim 0.53$) and retrograde orbit. Since the extreme chemical anomaly of 2M16011638-1201525 has also been observed in halo field stars, this object could also be considered a halo contaminant, likely been ejected into the Milky Way disk from the halo. We conclude that, 2M16011638-20152 is also kinematically consistent with the disk but chemically consistent with halo field stars.

Accepted for publication in ApJ

References in corpus (17)

• The Gaia mission
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• A new implementation of the infrared flux method using the 2MASS catalogue
• Spectroscopic and Photometric evidence of two stellar populations in the Galactic Globular Cluster NGC6121 (M4)
• Constraining the thick disc formation scenario of the Milky Way
• Exploring Anticorrelations and Light Element Variations in Northern Globular Clusters Observed by the APOGEE Survey
• New H-band Stellar Spectral Libraries for the SDSS-III/APOGEE survey
• An accurate and self-consistent chemical abundance catalogue for the APOGEE/Kepler sample
• A new abundance scale for the globular cluster 47 Tuc
• Chemical tagging in the SDSS-III/APOGEE survey: new identifications of halo stars with globular cluster origins
• The metallicity spread and the age-metallicity relation of Omega Centauri
• The Gaia-ESO Survey: A globular cluster escapee in the Galactic halo
• Searching for tidal tails around $\omega$ Centauri using RR Lyrae Stars
• A Global Correction to PPMXL Proper Motions
• Close encounters involving RAVE stars beyond the 47 Tucanae tidal radius

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