Mapping young stellar populations towards Orion with Gaia DR1

Abstract

We use the first data release of the Gaia mission to explore the three dimensional arrangement and the age ordering of the many stellar groups towards the Orion OB association, aiming at a new classification and characterization of the stellar population. We make use of the parallaxes and proper motions provided in the Tycho Gaia Astrometric Solution (TGAS) sub-set of the Gaia catalogue, and of the combination of Gaia and 2MASS photometry. In TGAS we find evidence for the presence of a young population, at a parallax $\varpi \sim 2.65\mathrm{mas}$, loosely distributed around some known clusters: 25 Ori, $\epsilon$ Ori and $\sigma$ Ori, and NGC 1980 ($\iota$ Ori). The low mass counterpart of this population is visible in the color-magnitude diagrams constructed by combining Gaia and 2MASS photometry. We study the density distribution of the young sources in the sky. We find the same groups as in TGAS, and also some other density enhancements that might be related to the recently discovered Orion X group, the Orion dust ring, and to the $\lambda$ Ori complex. We estimate the ages of this population and we infer the presence of an age gradient going from 25 Ori (13-15 Myr) to the ONC (1-2 Myr). We confirm this age ordering by repeating the Bayesian fit using the Pan-STARRS1 data. The estimated ages towards the NGC 1980 cluster span a broad range of values. This can either be due to the presence of two populations coming from two different episodes of star formation or to a large spread along the line of sight of the same population. Our results form the first step towards using the Gaia data to unravel the complex star formation history of the Orion region in terms of the different star formation episodes, their duration, and their effects on the surrounding interstellar medium.

arXiv comment17 pages, 17 figures

References in corpus (46)

• The Gaia mission
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones
• A Hipparcos census of the nearby OB associations
• Planck 2013 results. XI. All-sky model of thermal dust emission
• The distance to the Orion Nebula
• Improving PARSEC models for very low mass stars
• Gaia Data Release 1: Astrometry - one billion positions, two million proper motions and parallaxes
• A Full-Sky H-alpha Template for Microwave Foreground Prediction
• Spitzer Space Telescope study of disks in the young $\sigma$ Orionis cluster
• New PARSEC evolutionary tracks of massive stars at low metallicity: testing canonical stellar evolution in nearby star forming dwarf galaxies
• Gaia broad band photometry
• Introduction to astroML: Machine Learning for Astrophysics
• Pre-main-sequence isochrones -- II. Revising star and planet formation timescales
• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• Lithium and Halpha in stars and brown dwarfs of sigma Orionis
• Distance to Orion KL Measured with VERA
• A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations
• Quantitative Evidence for an Intrinsic Age Spread in the Orion Nebula Cluster
• Tracing the young massive high-eccentricity binary system Theta 1 Orionis C through periastron passage
• IN-SYNC IV - The Young Stellar Population in the Orion A Molecular Cloud
• Dynamical Mass Constraints on Low-Mass Pre-Main-Sequence Stellar Evolutionary Tracks: An Eclipsing Binary in Orion with a 1.0 Msun Primary and an 0.7 Msun Secondary
• 25 Orionis: A Kinematically Distinct 10 Myr Old Group in Orion OB1a
• Orion Revisited - I. The massive cluster in front of the Orion Nebula Cluster
• A refurbished convergent point method for finding moving groups in the Hipparcos Catalogue
• A Tale of Three Cities: OmegaCAM discovers multiple sequences in the color-magnitude diagram of the Orion Nebula Cluster
• Kinematic structure in the young Sigma Orionis association
• Main-Seqence Fitting Distance to the sigma Ori Cluster
• The Structure, Dynamics and Star Formation Rate of the Orion Nebula Cluster
• The distance to the Orion Nebula Cluster
• Gaia data release 1: Principles of the photometric calibration of the G band
• Core-Halo Age Gradients and Star Formation in the Orion Nebula and NGC~2024 Young Stellar Clusters
• Nested shells reveal the rejuvenation of the Orion-Eridanus superbubble
• Orion revisited. II. The foreground population to Orion A
• Gaia data release 1, the photometric data
• Identification of Moving Groups and Member Selection using Hipparcos Data
• NGC 1980 is not a foreground population of Orion: Spectroscopic survey of young stars with low extinction in Orion A
• Gaia Data Release 1. Cross-match with external catalogues - Algorithm and results
• 3D Dust Mapping Reveals that Orion Forms Part of a Large Ring of Dust
• The old open cluster NGC 2112: updated estimates of fundamental parameters based on a membership analysis
• Orion revisited III. The Orion Belt population
• Bayesian isochrone fitting and stellar ages
• Characterizing the stellar population of NGC 1980
• A new method to unveil embedded stellar clusters

Cited by in corpus (23)

• The APOGEE-2 Survey of the Orion Star Forming Complex II: Six-dimensional structure
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18
• Untangling the Galaxy I: Local Structure and Star Formation History of the Milky Way
• 3D mapping of young stars in the solar neighbourhood with Gaia DR2
• Disruption of the Orion Molecular Core 1 by the stellar wind of the massive star ${\theta }^1$ Ori C
• OB associations and their origins
• Structure, kinematics, and ages of the young stellar populations in the Orion region
• Significance Mode Analysis (SigMA) for hierarchical structures. An application to the Sco-Cen OB association
• 3D Morphology of Open Clusters in the Solar Neighborhood with Gaia EDR3 II: Hierarchical Star Formation Revealed by Spatial and Kinematic Substructures
• The Gaia-ESO Survey: Asymmetric expansion of the Lagoon Nebula cluster NGC 6530 from GES and Gaia DR2
• Evidence for Radial Expansion at the Core of the Orion Complex with Gaia EDR3
• Detailed 3D structure of OrionA in dust with Gaia DR2
• Discovery of a 21 Myr old stellar population in the Orion complex
• Discovery of new stellar groups in the Orion complex
• Orion A's complete 3D magnetic field morphology
• System IMF of the 25 Ori Group from Planetary-Mass Objects to Intermediate/High-Mass Stars
• Carbon radio recombination lines from gigahertz to megahertz frequencies towards Orion A
• The cosmic-ray content of the Orion-Eridanus superbubble
• The ionization fraction in OMC-2 and OMC-3
• Gaia: the Galaxy in six (and more) dimensions
• A complete Herbig disk mass survey in Orion
• Pre-main sequence population of Sco-Cen unveiled with Gaia DR2
• Spectropolarimetry of Magnetic Chemically Peculiar Stars in the Orion OB1 Association