TY - JOUR
T1 - Mixing of metals during star cluster formation
T2 - Statistics and implications for chemical tagging
AU - Armillotta, Lucia
AU - Krumholz, Mark R.
AU - Fujimoto, Yusuke
N1 - Publisher Copyright:
© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.
PY - 2018/12/1
Y1 - 2018/12/1
N2 - Ongoing surveys are in the process of measuring the chemical abundances in large numbers of stars, with the ultimate goal of reconstructing the formation history of the MilkyWay using abundances as tracers. However, interpretation of these data requires that we understand the relationship between stellar distributions in chemical and physical space. We investigate this question by simulating the gravitational collapse of a turbulent molecular cloud extracted from a galaxy-scale simulation, seeded with chemical inhomogeneities with different initial spatial scales. We follow the collapse from galactic scales down to resolutions scales of ≈10-3 pc, and find that, during this process, turbulence mixes the metal patterns, reducing the abundance scatter initially present in the gas by an amount that depends on the initial scale of inhomogeneity of each metal field. However, we find that regardless of the spatial structure of the metals at the onset of collapse, the final stellar abundances are highly correlated only on distances below a few pc. Consequently, the star formation process defines a natural size scale of ~1 pc for chemically homogeneous star clusters, suggesting that any clusters identified as homogeneous in chemical space must have formed within ~1 pc of one another. However, in order to distinguish different star clusters in chemical space, observations across multiple elements are required, and the elements that are likely to be most efficient at separating distinct clusters in chemical space are those whose correlation length in the interstellar medium is of the order of tens of pc, comparable to the sizes of individual molecular clouds.
AB - Ongoing surveys are in the process of measuring the chemical abundances in large numbers of stars, with the ultimate goal of reconstructing the formation history of the MilkyWay using abundances as tracers. However, interpretation of these data requires that we understand the relationship between stellar distributions in chemical and physical space. We investigate this question by simulating the gravitational collapse of a turbulent molecular cloud extracted from a galaxy-scale simulation, seeded with chemical inhomogeneities with different initial spatial scales. We follow the collapse from galactic scales down to resolutions scales of ≈10-3 pc, and find that, during this process, turbulence mixes the metal patterns, reducing the abundance scatter initially present in the gas by an amount that depends on the initial scale of inhomogeneity of each metal field. However, we find that regardless of the spatial structure of the metals at the onset of collapse, the final stellar abundances are highly correlated only on distances below a few pc. Consequently, the star formation process defines a natural size scale of ~1 pc for chemically homogeneous star clusters, suggesting that any clusters identified as homogeneous in chemical space must have formed within ~1 pc of one another. However, in order to distinguish different star clusters in chemical space, observations across multiple elements are required, and the elements that are likely to be most efficient at separating distinct clusters in chemical space are those whose correlation length in the interstellar medium is of the order of tens of pc, comparable to the sizes of individual molecular clouds.
KW - Hydrodynamics
KW - Methods: numerical
KW - Open clusters and associations: general
KW - Stars: abundances
KW - Turbulence
UR - http://www.scopus.com/inward/record.url?scp=85056767324&partnerID=8YFLogxK
U2 - 10.1093/MNRAS/STY2625
DO - 10.1093/MNRAS/STY2625
M3 - Article
SN - 0035-8711
VL - 481
SP - 5000
EP - 5013
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -