The historical record of massive star formation in Cygnus

Abstract

The Cygnus region, which dominates the local spiral arm of the Galaxy, is one of the nearest complexes of massive star formation. Its massive stellar content, regions of ongoing star formation, and molecular gas have been studied in detail. However, little is known of the history of the region beyond the past 10 Myr. The brightness and spectroscopic characteristics of red supergiants make it easy to identify them and build up a virtually complete sample of such stars at the distance of the Cygnus region, thus providing a record of massive star formation extending several tens of Myr into the past, a period inaccessible through the O and early B stars observable at present. We have made a selection of a sample of bright, red stars in an area of 84 square degrees covering the whole present extension of the Cygnus region. We have obtained spectroscopy in the red visible range allowing an accurate, homogeneous spectral classification as well as a reliable separation between supergiants and other cool stars. Our data are complemented with Gaia Data Release 2 astrometric data. We have identified 29 red supergiants in the area, 17 of which had not been previously classified as supergiants. Twenty-four of the 29 most likely belong to the Cygnus region and four of the remaining to the Perseus arm. We have used their derived luminosities and masses to infer the star formation history of the region. Intense massive star formation activity is found to have started approximately 15 Myr ago, and we find evidence for two other episodes, one taking place between 20 and 30 Myr ago and another one having ended approximately 40 Myr ago. There are small but significant differences between the kinematic properties of red supergiants younger or older then 20 Myr, hinting that stars of the older group were formed outside the precursor of the present Cygnus complex, possibly in the Sagittarius-Carina arm.

arXiv commentAccepted for publication in Astronomy and Astrophysics

References in corpus (44)

• Gaia Data Release 2: The astrometric solution
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• A Hipparcos census of the nearby OB associations
• The mass distribution and gravitational potential of the Milky Way
• Color Transformations for the 2MASS Second Incremental Data Release
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• Gaia Data Release 2: using Gaia parallaxes
• A Gaia DR2 view of the Open Cluster population in the Milky Way
• Astrophysical parameters of Galactic open clusters
• Northern Sky Variability Survey (NSVS): Public data release
• The Effective Temperature Scale of Galactic Red Supergiants: Cool, But Not As Cool As We Thought
• Parallaxes and proper motions of interstellar masers toward the Cygnus X star-forming complex. I. Membership of the Cygnus X region
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• Clusters and mirages: cataloguing stellar aggregates in the Milky Way
• A Stellar Rotation Census of B Stars: from ZAMS to TAMS
• ON the Nature of the Local Spiral Arm of the Milky Way
• A Study of Cyg OB2: Pointing the Way Towards Finding Our Galaxy's Super Star Clusters
• Distances and parallax bias in Gaia DR2
• The Massive Star Population of Cygnus OB2
• Broad-band photometric colors and effective temperature calibrations for late-type giants. I. Z=0.02
• The local spiral structure of the Milky Way
• Late-Type Red Supergiants: Too Cool for the Magellanic Clouds?
• New very massive stars in Cygnus OB2
• Convergent flows and low-velocity shocks in DR21(OH)
• Hic sunt dracones: Cartography of the Milky Way spiral arms and bar resonances with Gaia Data Release 2
• Early-A stars from IPHAS, and their distribution in and around the Cyg OB2 association
• The Galactic spiral structure as revealed by O- and early B-type stars
• Internal motions in OB-associations with Gaia DR2
• A spectroscopic investigation of the O-type star population in four Cygnus OB associations. II. Determination of the fundamental parameters
• Convective cells in Betelgeuse: imaging through spectropolarimetry
• The outskirts of Cygnus OB2
• New massive members of Cygnus OB2
• Physical Properties of Red Supergiants
• Streaming Motions and Kinematic Distances to Molecular Clouds
• Red supergiants and stellar evolution
• Statistics on 24 spiral galaxies having different observed arm locations using different arm tracers
• Meta-analysis from different tracers of the small Local Arm around the Sun - extent, shape, pitch, origin
• Kinematic study of the association Cyg OB3 with Gaia DR2
• The Enigma of the Open Cluster M29 (NGC 6913) Solved
• Analysis of the Kinematic Structure of the Cygnus OB1 association
• The spiral potential of the Milky Way
• Young open cluster IC 4996 and its vicinity: multicolor photometry and Gaia DR2 astrometry
• Star-forming regions at the periphery of the supershell surrounding the Cyg OB1 association. I. The star cluster vdB 130 and its ambient gas and dust medium
• On the possible common origin of M16 and M17

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• Filamentary structures of ionized gas in Cygnus X
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• A low density-wave spiral pattern speed, from the tracer separations (age gradient) across a spiral arm in the Milky Way
• Subaru Hyper Suprime-Cam Survey of Cygnus OB2 Complex -- I: Introduction, Photometry and Source Catalog
• A Spatial Gap in the Sky Distribution of Fast Radio Burst Detections Coinciding with Galactic Plasma Overdensities
• Star formation in two irradiated globules around Cygnus OB2
• Deciphering the gamma-ray emission in the Cygnus region