Expanding shells around young clusters -- S 171/Be 59
arXiv:2205.05372 · doi:10.1051/0004-6361/202142927
Abstract
Some HII regions that surround young stellar clusters are bordered by molecular shells that appear to expand at a rate inconsistent with our current model simulations. In this study we focus on the dynamics of Sharpless 171 (including NGC 7822), which surrounds the cluster Berkeley 59. We aim to compare the velocity pattern over the molecular shell with the mean radial velocity of the cluster for estimates of the expansion velocities of different shell structures, and to match the observed properties with model simulations. Optical spectra of 27 stars located in Berkeley 59 were collected at the Nordic Optical Telescope, and a number of molecular structures scattered over the entire region were mapped in CO(1-0) at Onsala Space Observatory. We obtained radial velocities and MK classes for the cluster's stars. At least four of the O stars are found to be spectroscopic binaries, in addition to one triplet system. From these data we obtain the mean radial velocity of the cluster. From the CO spectra we identify three shell structures, expanding relative to the cluster at moderate velocity (4 km/s), high velocity (12 km/s), and in between. The high-velocity cloudlets extend over a larger radius and are less massive than the low-velocity cloudlets. We performed a model simulation to understand the evolution of this complex. Our simulation of the Sharpless 171 complex and Berkeley 59 cluster demonstrates that the individual components can be explained as a shell driven by stellar winds from the massive cluster members. However, our relatively simple model produces a single component. Modelling of the propagation of shell fragments through a uniform interstellar medium demonstrates that dense cloudlets detached from the shell are decelerated less efficiently than the shell itself. They can reach greater distances and retain higher velocities than the shell.
arXiv comment27 pages, 14 figures, 8 tables, 3 appendices. Accepted for publication in Astronomy & Astrophysics
References in corpus (40)
- Array Programming with NumPy
- Gaia Data Release 2. Summary of the contents and survey properties
- Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
- New catalogue of optically visible open clusters and candidates
- Astrophysical parameters of Galactic open clusters
- Empirical extinction coefficients for the GALEX, SDSS, 2MASS and WISE passbands
- Kinematics in Young Star Clusters and Associations with Gaia DR2
- A spectroscopic survey on the multiplicity of high-mass stars
- Supernova Type Ia progenitors from merging double white dwarfs: Using a new population synthesis model
- Before the first supernova: combined effects of HII regions and winds on molecular clouds
- A catalog of newly identified star clusters in GAIA DR2
- Ionizing Photon Emission Rates from O- and Early B-type Stars and Clusters
- Massive stars and the energy balance of the ISM. I. The impact of an isolated 60 Msun star
- Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. II. On the Generality of Triggered Star Formation
- Radiation-magnetohydrodynamic simulations of HII regions and their associated PDRs in turbulent molecular clouds
- BRIDGE: A Direct-tree Hybrid N-body Algorithm for Fully Self-consistent Simulations of Star Clusters and their Parent Galaxies
- The modelling of feedback in star formation simulations
- Efficiently Cooled Stellar Wind Bubbles in Turbulent Clouds I. Fractal Theory and Application to Star-Forming Clouds
- StarBench: The D-type expansion of an HII region
- Efficiently Cooled Stellar Wind Bubbles in Turbulent Clouds II. Validation of Theory with Hydrodynamic Simulations
- Periodic bursts of Star Formation in Irregular Galaxies
- 3D simulations of globules and pillars formation around HII regions: turbulence and shock curvature
- N-body Integrators with Individual Time Steps from Hierarchical Splitting
- MONOS: Multiplicity Of Northern O-type Spectroscopic systems. I. Project description and spectral classifications and visual multiplicity of previously known objects
- Star Formation In Nearby Clouds (SFiNCs): X-ray And Infrared Source Catalogs And Membership
- Stellar contents and star formation in the young star cluster Be 59
- Modelling of the Effects of Stellar Feedback during Star Cluster Formation Using a Hybrid Gas and N-Body Method
- Pillars and globules at the edges of H ii regions, Confronting Herschel observations and numerical simulations
- The OCCASO survey: Presentation and radial velocities of twelve Milky Way Open Clusters
- When H II Regions are Complicated: Considering Perturbations from Winds, Radiation Pressure, and Other Effects
- Synthetic observations of star formation and the interstellar medium
- 3D simulations of pillars formation around HII regions: the importance of shock curvature
- Intracluster Age Gradients In Numerous Young Stellar Clusters
- Young Star Clusters In Nearby Molecular Clouds
- Young cluster Berkeley 59 : Properties, evolution and star formation
- MONOS.II. Orbit review and analysis for 35 single-lined spectroscopic binary systems and candidates
- Photometric search for variable stars in young open cluster Berkeley 59
- Simulating stellar winds in AMUSE
- Testing Models of Triggered Star Formation with Young Stellar Objects in Cepheus OB4
- Expanding shells around young clusters -- S 171/Be 59