The Parent Populations of 6 groups identified from Chemical Tagging in the Solar neighborhood

Abstract

We estimate the size and distribution of the parent populations for the 6 largest (at least 20 stars in the Solar neighborhood) chemical groups identified in the Chemical Tagging experiment by Mitschang et al.~2014. Stars in the abundance groups tend to lie near a boundary in angular momentum versus eccentricity space where the probability is highest for a star to be found in the Solar neighborhood and where orbits have apocenter approximately equal to the Sun's galactocentric radius. Assuming that the parent populations are uniformly distributed at all azimuthal angles in the Galaxy, we estimate that the parent populations of these abundance groups contain at least 200,000 members. The spread in angular momentum of the groups implies that the assumption of a uniform azimuthal distribution only fails for the two youngest groups and only for the highest angular momentum stars in them. The parent populations of three thin disk groups have narrow angular momentum distributions, but tails in the eccentricity and angular momentum distributions suggest that only a small fraction of stars have migrated and increased in eccentricity. In contrast, the parent populations of the thick disk groups exhibit both wide angular momentum and eccentricity distributions implying that both heating and radial migration has taken place.

accepted for publication in MNRAS

References in corpus (6)

• The GALAH Survey: Scientific Motivation
• Is the Milky Way ringing? The hunt for high velocity streams
• Chemically Tagging the HR1614 Moving Group
• The absolute motion of the peculiar cluster NGC6791
• The Milky Way as a High Redshift Galaxy: The Importance of Thick Disk Formation in Galaxies
• Quest for finding the lost siblings of the Sun

Cited by in corpus (11)

• Star Clusters Across Cosmic Time
• Identifying the best iron-peak and $\alpha$-capture elements for chemical tagging: The impact of the number of lines on measured scatter
• Chemical tagging can work: Identification of stellar phase-space structures purely by chemical-abundance similarity
• The Surface Density Profile of the Galactic Disk from the Terminal Velocity Curve
• Prospects for Measuring Abundances of >20 Elements with Low-resolution Stellar Spectra
• The GALAH survey: Chemical Tagging of Star Clusters and New Members in the Pleiades
• APOGEE chemical tagging constraint on the maximum star cluster mass in the $\alpha$-enhanced Galactic disk
• The velocity ellipsoid in the Galactic disc using Gaia DR1
• From birth associations to field stars: mapping the small-scale orbit distribution in the Galactic disc
• Tidal debris from Omega Centauri discovered with unsupervised machine learning
• The GALAH survey: Multiple stars and our Galaxy. I. A comprehensive method for deriving properties of FGK binary stars