From birth associations to field stars: mapping the small-scale orbit distribution in the Galactic disc

  title={From birth associations to field stars: mapping the small-scale orbit distribution in the Galactic disc},
  author={Johanna Coronado and Hans–Walter Rix and Wilma H. Trick and Kareem El-Badry and Jan Rybizki and Maosheng Xiang},
  journal={Monthly Notices of the Royal Astronomical Society},
  • J. Coronado, H. Rix, M. Xiang
  • Published 21 February 2020
  • Physics, Geology
  • Monthly Notices of the Royal Astronomical Society
Stars born at the same time in the same place should have formed from gas of the same element composition. But most stars subsequently disperse from their birth siblings, in orbit and orbital phase, becoming 'field stars'. Here we explore and provide direct observational evidence for this process in the Milky Way disc, by quantifying the probability that orbit-similarity among stars implies indistinguishable metallicity. We define the orbit similarity among stars through their distance in… 

Figures from this paper

The power of coordinate transformations in dynamical interpretations of Galactic structure

$Gaia$ DR2 has provided an unprecedented wealth of information about the positions and motions of stars in our Galaxy, and has highlighted the degree of disequilibria in the disc. As we collect data

Chemically Peculiar A and F Stars with Enhanced s-process and Iron-peak Elements: Stellar Radiative Acceleration at Work

We present ≳15,000 metal-rich ([Fe/H] > −0.2 dex) A and F stars whose surface abundances deviate strongly from solar abundance ratios and cannot plausibly reflect their birth material composition.

Pearls on a String: Numerous Stellar Clusters Strung Along the Same Orbit

Stars originate from the dense interstellar medium, which exhibits filamentary structure to scales of ∼1 kpc in galaxies like our Milky Way. We explore quantitatively how much resulting large-scale

Measuring Chemical Likeness of Stars with Relevant Scaled Component Analysis

Identification of chemically similar stars using elemental abundances is core to many pursuits within Galactic archeology. However, measuring the chemical likeness of stars using abundances directly

Disentangled Representation Learning for Astronomical Chemical Tagging

A data-driven method for isolating the chemical factors of variation in stellar spectra from those of other parameters (i.e., T eff, log g, [Fe/H]), which enables to build a spectral projection for each star with these parameters removed.

Age–metallicity dependent stellar kinematics of the Milky Way disc from LAMOST and Gaia

We investigate the stellar kinematics of the Galactic disc in 7 < R < 13 kpc using a sample of 118 945 red giant branch (RGB) stars from LAMOST and Gaia. We characterize the median, dispersion and

Spatial and Kinematic Clustering of Stars in the Galactic Disk

The Galactic disk is expected to be spatially and kinematically clustered on many scales due to both star formation and the Galactic potential. In this work we calculate the spatial and kinematic

The ACTIONFINDER: An Unsupervised Deep Learning Algorithm for Calculating Actions and the Acceleration Field from a Set of Orbit Segments

We introduce the ACTIONFINDER, a deep learning algorithm designed to transform a sample of phase-space measurements along orbits in a static potential into action and angle coordinates. The algorithm

Orbital Torus Imaging: Using Element Abundances to Map Orbits and Mass in the Milky Way

Many approaches to galaxy dynamics assume that the gravitational potential is simple and the distribution function is time invariant. Under these assumptions there are traditional tools for inferring



Galactic Doppelgängers: The Chemical Similarity Among Field Stars and Among Stars with a Common Birth Origin

We explore to what extent stars within Galactic disk open clusters resemble each other in the high-dimensional space of their photospheric element abundances and contrast this with pairs of field

Measuring Radial Orbit Migration in the Galactic Disk

We develop and apply a model to quantify the global efficiency of radial orbit migration among stars in the Milky Way disk. This model parameterizes the possible star formation and enrichment

Stars that Move Together Were Born Together

It is challenging to reliably identify stars that were born together outside of actively star-forming regions and bound stellar systems. However, conatal stars should be present throughout the


The Galactic disk retains vast amount of information about how it came to be and how it evolved over cosmic time. However, we know very little about the secular processes associated with disk

The Galactic disc in action space as seen byGaiaDR2

The quality and quantity of 6D stellar position-velocity measurements in the second Gaia data release (DR2) allows to study small-scale structure in the orbit distribution of the Galactic disc beyond

Extended stellar systems in the solar neighborhood

We present a novel view on the morphology and dynamical state of ten prominent, nearby (≤500 pc), and young (∼30–300 Myr) open star clusters with Gaia DR2: α Per, Blanco 1, IC 2602, IC 2391, Messier


It is now well-established that the elemental abundance patterns of stars hold key clues not only to their formation, but also to the assembly histories of galaxies. One of the most exciting

HIPPARCOS age metallicity relation of the solar neighbourhood disc stars

We derive age-metallicity relations (AMRs) and orbital parameters for the 1658 solar neighbourhood stars to which accurate distances are measured by the HIPPARCOS satellite. The sample stars comprise

The parent populations of six groups identified from chemical tagging in the solar neighbourhood

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

The contribution of dissolving star clusters to the population of ultra faint objects in the outer halo of the Milky Way

In the last decade, several ultra faint objects (UFOs, MV −3.5) have been discovered in the outer halo of the Milky Way. For some of these objects, it is not clear whether they are star clusters or