Runaways and shells around the CMa OB1 association

Abstract

The origin of the arc-shaped Sh2-296 nebula is still unclear. Mainly due to its morphology, the nebula has been suggested to be a 0.5 Myr-old supernova remnant (SNR) that could be inducing star formation in the CMa OB1 association. We aim to show, for the first time, that the nebula is part of a large, shell-like structure, which we have designated the ``CMa shell'', enclosing a bubble created by successive supernova (SN) explosions. We identified three runaway stars, associated with bow-shock structures, in the direction of the CMa shell and we investigate the possibility that they have originated in the center of the shell. By analyzing images of the CMa OB1 association at several wavelengths, we clearly see that the Sh2-296 nebula is in fact part of a large structure, which can be approximated by a large (with a diameter of ~60 pc) elliptical shell. Using the recent Gaia-DR2 astrometric data, we trace back the path of the three runaway stars, in order to find their original position in the past, with relation to the CMa shell. We also revise the heating and ionization of the Sh2-296 nebula, by comparing the photon budget provided by the O stars in the region with results from radio observations. We find that the runaway stars have likely been ejected from a Trapezium-like progenitor cluster on three successive SN explosions having taken place ~6, ~2 and ~1 Myr ago. We also show that the few late-type O stars in the region cannot explain the ionization of the Sh~2-296 nebula and other mechanisms need to be at work. We argue that, though we now have evidence for several SNe events in the CMa OB1 association, the SNe probably played a minor role in triggering star formation in these clouds. In contrast, the CMa OB1 association, as it is now, likely testifies to the last stages of a star-forming region.

arXiv comment15 pages, 10 figures, accepted by A&A

References in corpus (48)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Validation of the new Hipparcos reduction
• Local Kinematics and the Local Standard of Rest
• A new calibration of stellar parameters of Galactic O stars
• The Infrared Astronomical Mission AKARI
• Astrophysical parameters of Galactic open clusters
• The SuperCOSMOS Sky Survey. Paper I: Introduction and Description
• Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
• The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars
• The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-Violet at R~2500
• Pulkovo Compilation of Radial Velocities for 35495 Hipparcos Stars in a Common System
• A catalogue of young runaway Hipparcos stars within 3kpc from the Sun
• Signatures of a two million year old supernova in the spectra of cosmic ray protons, antiprotons and positrons
• X-Rays from Superbubbles in the Large Magellanic Cloud. VI. A Sample of Thirteen Superbubbles
• The Galactic Distribution of Large HI Shells
• A comprehensive search for stellar bowshock nebulae in the Milky Way: a catalog of 709 mid-infrared selected candidates
• E-BOSS: An Extensive stellar BOw Shock Survey. II. Catalogue second release
• Cosmic ray induced ionisation of a molecular cloud shocked by the W28 supernova remnant
• A very massive runaway star from Cygnus OB2
• Astrophysical Shrapnel: Discriminating Among Near-Earth Stellar Explosion Sources of Live Radioactive Isotopes
• Nested shells reveal the rejuvenation of the Orion-Eridanus superbubble
• Hierarchical progressive surveys. Multi-resolution HEALPix data structures for astronomical images, catalogues, and 3-dimensional data cubes
• Feedback by massive stars and the emergence of superbubbles II. X-ray properties
• A WISE Census of Young Stellar Objects in Canis Major
• Dynamics and Energy Loss in Superbubbles
• GSH 138-01-94, an old supernova remnant in the far outer Galaxy
• A molecular shell with star formation toward the supernova remnant G349.7+0.2
• A new catalog of HI supershell candidates in the outer part of the Galaxy
• A Young GMC Formed at the Interface of Two Colliding Supershells: Observations Meet Simulations
• CMF models of hot star winds I. Test of the Sobolev approximation in the case of pure line transitions
• XMM-Newton observations of a superbubble in N 158 in the LMC
• Kompaneets Model Fitting of the Orion-Eridanus Superbubble II: Thinking Outside of Barnard's Loop
• XMM-Newton view of the N 206 superbubble in the Large Magellanic Cloud
• Star formation history of CMa R1: I. Wide-field X-ray study of the young stellar population
• The Neutron Star Born in the Antlia Supernova Remnant
• Star formation activity in the Galactic H II region Sh2-297
• New Young Star Candidates in BRC 27 and BRC 34
• The Stellar Composition of the Star Formation Region CMa R1. II. Spectroscopic and Photometric Observations of 9 Young Stars
• Low-Mass Runaway Stars from the Orion Trapezium Cluster
• Extended Red Objects and Stellar Wind Bow Shocks in the Carina Nebula
• Spectroscopic characterization of X-ray emitting young stars associated with the Sh 2-296 nebula
• Star formation history of Canis Major OB1 - II. A bimodal X-ray population revealed by XMM-Newton
• Instability, finite amplitude pulsation and mass-loss in models of massive OB-type stars
• The long-period massive binary HD~54662 revisited
• FIT{\it spec}: a new algorithm for the automated fit of synthetic stellar spectra for OB stars
• GSH 90-28-17: a Possible Old Supernova Remnant
• Galactic HI supershells: Kinetic energies and possible origin

Cited by in corpus (13)

• OB associations and their origins
• Molecular cloud catalogue from ${}^{13}$CO(1-0) data of the Forgotten Quadrant Survey
• Quantitative spectroscopy of late O-type main-sequence stars with a hybrid non-LTE method
• Canis Major OB1 stellar groups contents revealed by Gaia
• Halpha emission-line stars in molecular clouds III. Canis Major
• Searching for active low-mass stars in CMa star-forming region: multi-band photometry with T80S
• The K supergiant runaway star HD 137071
• A High-Mass Young Star-forming Core Escaping from Its Parental Filament
• Survey of Profile Parameters of the $6196\mathring{A}$ Diffuse Interstellar Band. From Uniform Profiles to Doppler Splitting and Blueshifts
• Large-Scale Ejecta of Z CMa -- Proper Motion Study and New Features Discovered
• Current status and future plan of Osaka Prefecture University 1.85-m mm-submm telescope project
• Comparing the spatial and kinematic distribution of gas and young stars around the shell-like structure in the CMa OB1 association
• A closer look at the young stellar group around Sh 2-295