Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud

M. S. Oey, J. Dorigo Jones, N. Castro, P. Zivick, Gurtina Besla, H. C. Januszewski, M. Moe, N. Kallivayalil, D. J. Lennon

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We use Gaia Data Release 2 proper motions of field OB stars from the Runaways and Isolated O-Type Star Spectroscopic Survey of the Small Magellanic Cloud (SMC) to study the kinematics of runaway stars. The data reveal that the SMC Wing has a systemic peculiar motion relative to the SMC Bar of (vα, vδ) = (62 ± 7, -18 ± 5) km s-1 and relative radial velocity +4.5 ± 5.0 km s-1. This unambiguously demonstrates that these two regions are kinematically distinct: the Wing is moving away from the Bar, and towards the Large Magellanic Cloud with a 3D velocity of 64 ± 10 km s-1. This is consistent with models for a recent, direct collision between the Clouds. We present transverse velocity distributions for our field OB stars, confirming that unbound runaways comprise on the order of half our sample, possibly more. Using eclipsing binaries and double-lined spectroscopic binaries as tracers of dynamically ejected runaways, and high-mass X-ray binaries (HMXBs) as tracers of runaways accelerated by supernova kicks, we find significant contributions from both populations. The data suggest that HMXBs have lower velocity dispersion relative to dynamically ejected binaries, consistent with the former group corresponding to less energetic supernova kicks that failed to unbind the components. Evidence suggests that our fast runaways are dominated by dynamical, rather than supernova, ejections.

Original languageEnglish (US)
Article numberL8
JournalAstrophysical Journal Letters
Volume867
Issue number1
DOIs
StatePublished - Nov 1 2018

Fingerprint

star distribution
Magellanic clouds
kinematics
supernovae
wings
tracers
tracer
stars
proper motion
ejection
radial velocity
low speed
x rays
energetics
velocity distribution
collision
collisions

Keywords

  • binaries: general
  • galaxies: star clusters: general
  • Magellanic Clouds
  • stars: kinematics and Dynamics
  • stars: massive
  • X-rays: binaries

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Oey, M. S., Jones, J. D., Castro, N., Zivick, P., Besla, G., Januszewski, H. C., ... Lennon, D. J. (2018). Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud. Astrophysical Journal Letters, 867(1), [L8]. https://doi.org/10.3847/2041-8213/aae892

Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud. / Oey, M. S.; Jones, J. Dorigo; Castro, N.; Zivick, P.; Besla, Gurtina; Januszewski, H. C.; Moe, M.; Kallivayalil, N.; Lennon, D. J.

In: Astrophysical Journal Letters, Vol. 867, No. 1, L8, 01.11.2018.

Research output: Contribution to journalArticle

Oey, MS, Jones, JD, Castro, N, Zivick, P, Besla, G, Januszewski, HC, Moe, M, Kallivayalil, N & Lennon, DJ 2018, 'Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud', Astrophysical Journal Letters, vol. 867, no. 1, L8. https://doi.org/10.3847/2041-8213/aae892
Oey, M. S. ; Jones, J. Dorigo ; Castro, N. ; Zivick, P. ; Besla, Gurtina ; Januszewski, H. C. ; Moe, M. ; Kallivayalil, N. ; Lennon, D. J. / Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud. In: Astrophysical Journal Letters. 2018 ; Vol. 867, No. 1.
@article{4ed7c03396fa4856932dc2160ece540d,
title = "Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud",
abstract = "We use Gaia Data Release 2 proper motions of field OB stars from the Runaways and Isolated O-Type Star Spectroscopic Survey of the Small Magellanic Cloud (SMC) to study the kinematics of runaway stars. The data reveal that the SMC Wing has a systemic peculiar motion relative to the SMC Bar of (vα, vδ) = (62 ± 7, -18 ± 5) km s-1 and relative radial velocity +4.5 ± 5.0 km s-1. This unambiguously demonstrates that these two regions are kinematically distinct: the Wing is moving away from the Bar, and towards the Large Magellanic Cloud with a 3D velocity of 64 ± 10 km s-1. This is consistent with models for a recent, direct collision between the Clouds. We present transverse velocity distributions for our field OB stars, confirming that unbound runaways comprise on the order of half our sample, possibly more. Using eclipsing binaries and double-lined spectroscopic binaries as tracers of dynamically ejected runaways, and high-mass X-ray binaries (HMXBs) as tracers of runaways accelerated by supernova kicks, we find significant contributions from both populations. The data suggest that HMXBs have lower velocity dispersion relative to dynamically ejected binaries, consistent with the former group corresponding to less energetic supernova kicks that failed to unbind the components. Evidence suggests that our fast runaways are dominated by dynamical, rather than supernova, ejections.",
keywords = "binaries: general, galaxies: star clusters: general, Magellanic Clouds, stars: kinematics and Dynamics, stars: massive, X-rays: binaries",
author = "Oey, {M. S.} and Jones, {J. Dorigo} and N. Castro and P. Zivick and Gurtina Besla and Januszewski, {H. C.} and M. Moe and N. Kallivayalil and Lennon, {D. J.}",
year = "2018",
month = "11",
day = "1",
doi = "10.3847/2041-8213/aae892",
language = "English (US)",
volume = "867",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud

AU - Oey, M. S.

AU - Jones, J. Dorigo

AU - Castro, N.

AU - Zivick, P.

AU - Besla, Gurtina

AU - Januszewski, H. C.

AU - Moe, M.

AU - Kallivayalil, N.

AU - Lennon, D. J.

PY - 2018/11/1

Y1 - 2018/11/1

N2 - We use Gaia Data Release 2 proper motions of field OB stars from the Runaways and Isolated O-Type Star Spectroscopic Survey of the Small Magellanic Cloud (SMC) to study the kinematics of runaway stars. The data reveal that the SMC Wing has a systemic peculiar motion relative to the SMC Bar of (vα, vδ) = (62 ± 7, -18 ± 5) km s-1 and relative radial velocity +4.5 ± 5.0 km s-1. This unambiguously demonstrates that these two regions are kinematically distinct: the Wing is moving away from the Bar, and towards the Large Magellanic Cloud with a 3D velocity of 64 ± 10 km s-1. This is consistent with models for a recent, direct collision between the Clouds. We present transverse velocity distributions for our field OB stars, confirming that unbound runaways comprise on the order of half our sample, possibly more. Using eclipsing binaries and double-lined spectroscopic binaries as tracers of dynamically ejected runaways, and high-mass X-ray binaries (HMXBs) as tracers of runaways accelerated by supernova kicks, we find significant contributions from both populations. The data suggest that HMXBs have lower velocity dispersion relative to dynamically ejected binaries, consistent with the former group corresponding to less energetic supernova kicks that failed to unbind the components. Evidence suggests that our fast runaways are dominated by dynamical, rather than supernova, ejections.

AB - We use Gaia Data Release 2 proper motions of field OB stars from the Runaways and Isolated O-Type Star Spectroscopic Survey of the Small Magellanic Cloud (SMC) to study the kinematics of runaway stars. The data reveal that the SMC Wing has a systemic peculiar motion relative to the SMC Bar of (vα, vδ) = (62 ± 7, -18 ± 5) km s-1 and relative radial velocity +4.5 ± 5.0 km s-1. This unambiguously demonstrates that these two regions are kinematically distinct: the Wing is moving away from the Bar, and towards the Large Magellanic Cloud with a 3D velocity of 64 ± 10 km s-1. This is consistent with models for a recent, direct collision between the Clouds. We present transverse velocity distributions for our field OB stars, confirming that unbound runaways comprise on the order of half our sample, possibly more. Using eclipsing binaries and double-lined spectroscopic binaries as tracers of dynamically ejected runaways, and high-mass X-ray binaries (HMXBs) as tracers of runaways accelerated by supernova kicks, we find significant contributions from both populations. The data suggest that HMXBs have lower velocity dispersion relative to dynamically ejected binaries, consistent with the former group corresponding to less energetic supernova kicks that failed to unbind the components. Evidence suggests that our fast runaways are dominated by dynamical, rather than supernova, ejections.

KW - binaries: general

KW - galaxies: star clusters: general

KW - Magellanic Clouds

KW - stars: kinematics and Dynamics

KW - stars: massive

KW - X-rays: binaries

UR - http://www.scopus.com/inward/record.url?scp=85056119108&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85056119108&partnerID=8YFLogxK

U2 - 10.3847/2041-8213/aae892

DO - 10.3847/2041-8213/aae892

M3 - Article

VL - 867

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

SN - 2041-8205

IS - 1

M1 - L8

ER -