Schoettler, C, Parker, RJ, Arnold, B et al. (3 more authors) (2019) Dynamical evolution of star-forming regions: III. Unbound stars and predictions for Gaia. Monthly Notices of the Royal Astronomical Society, 487 (4). pp. 4615-4630. ISSN 0035-8711
Abstract
We use N-body simulations to probe the early phases of the dynamical evolution of star-forming regions and focus on mass and velocity distributions of unbound stars. In this parameter space study, we vary the initial virial ratio and degree of spatial and kinematic substructure and analyse the fraction of stars that become unbound in two different mass classes (above and below 8 M⊙). We find that the fraction of unbound stars differs depending on the initial conditions. After 10 Myr, in initially highly subvirial, substructured simulations, the high-mass and lower mass unbound fractions are similar at ∼23 per cent. In initially virialized, substructured simulations, we find only ∼16 per cent of all high-mass stars are unbound, whereas ∼37 per cent of all lower mass stars are. The velocity distributions of unbound stars only show differences for extremely different initial conditions. The distributions are dominated by large numbers of lower mass stars becoming unbound just above the escape velocity of ∼3 km s−1 with unbound high-mass stars moving faster on average than lower mass unbound stars. We see no high-mass runaway stars (velocity > 30 km s−1) from any of our initial conditions and only an occasional lower mass runaway star from initially subvirial/substructured simulations. In our simulations, we find a small number of lower mass walkaway stars (with velocity 5–30 km s−1) from all of our initial conditions. These walkaway stars should be observable around many nearby star-forming regions with Gaia.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). This is an author produced version of an article published in Monthly Notices of the Royal Astronomical Society. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | methods: numerical, stars: formation, stars: kinematics and dynamics, open clusters and associations: general |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mathematics (Leeds) > Pure Mathematics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 23 Sep 2020 13:00 |
Last Modified: | 23 Sep 2020 13:00 |
Published Version: | http://dx.doi.org/10.1093/mnras/stz1487 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Identification Number: | 10.1093/mnras/stz1487 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:165766 |