J/ApJ/903/43 Kinematic & fundamental parameters; OB stars (Dorigo Jones+, 2020)
Runaway OB Stars in the Small Magellanic Cloud: Dynamical versus Supernova
Ejections.
Dorigo Jones J., Oey M.S., Paggeot K., Castro N., Moe M.
<Astrophys. J., 903, 43 (2020)>
=2020ApJ...903...43D 2020ApJ...903...43D
ADC_Keywords: Magellanic Clouds; Stars, OB; MK spectral classification;
Stars, masses; Effective temperatures
Keywords: Runaway stars ; Massive stars ; Small Magellanic Cloud ; Field
stars ; Stellar kinematics ; Binary stars ; Star clusters ; Be
stars ; Stellar rotation ; High mass x-ray binary stars
Abstract:
Runaway OB stars are ejected from their parent clusters via two
mechanisms, both involving multiple stars: the dynamical ejection
scenario (DES) and the binary supernova scenario (BSS). We constrain
the relative contributions from these two ejection mechanisms in the
Small Magellanic Cloud (SMC) using data for 304 field OB stars from
the spatially complete Runaways and Isolated O-Type Star Spectroscopic
Survey of the SMC (RIOTS4). We obtain stellar masses and projected
rotational velocities vrsini for the sample using RIOTS4 spectra,
and we use transverse velocities vloc from Gaia DR2 proper motions.
Kinematic analyses of the masses, vrsini, noncompact binaries,
high-mass X-ray binaries, and Oe/Be stars largely support predictions
for the statistical properties of the DES and BSS populations. We find
that dynamical ejections dominate over supernova ejections by a factor
of ∼2-3 in the SMC, and our results suggest a high frequency of DES
runaways and binary ejections. Objects seen as BSS runaways also
include two-step ejections of binaries that are reaccelerated by
supernova kicks. We find that two-step runaways likely dominate the
BSS runaway population. Our results further imply that any
contribution from in situ field OB star formation is small. Finally,
our data strongly support the post-mass-transfer model for the origin
of classical Oe/Be stars, providing a simple explanation for the
bimodality in the vrsini distribution and high, near-critical, Oe/Be
rotation velocities. The close correspondence of Oe/Be stars with BSS
predictions implies that the emission-line disks are long-lived.
Description:
In this paper, we perform a comprehensive follow-up analysis of the
preliminary work presented in Paper I (Oey+, 2018, J/ApJ/867/L8),
which exploits Gaia data for field OB stars in the Small Magellanic
Cloud (SMC). Our sample consists of 304 SMC field OB stars observed in
the spatially complete RIOTS4 survey
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 81 304 Kinematic data and fundamental parameters for
RIOTS4 field OB stars
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See also:
II/236 : UBVR CCD survey of the Magellanic clouds (Massey+, 2002)
J/AJ/123/855 : Magellanic Clouds Photometric Survey: SMC (Zaritsky+, 2002)
J/AJ/127/1632 : UBVR(UIT) photometry of O and OB stars in SMC (Oey+, 2004)
J/ApJS/161/118 : byHα photometry in open clusters (McSwain+, 2005)
J/AJ/133/1092 : vsini of B0-B3 stars in 7 young clusters (Wolff+, 2007)
J/AJ/137/3358 : Speckle interferometry of massive stars (Mason+, 2009)
J/other/Sci/337.444 : RV curves of Galactic massive O stars (Sana+, 2012)
J/ApJ/763/101 : Massive field OB stars in the SMC (Lamb+, 2013)
J/AcA/63/323 : OGLE-III SMC eclipsing binary stars (Pawlak+, 2013)
J/A+A/562/A135 : Northern Galactic OB stars vsini (Simon-Diaz+, 2014)
J/A+A/564/A40 : VFTS. O-type stellar content of 30 Dor (Walborn+, 2014)
J/A+A/586/A81 : High-mass X-ray binaries in the SMC (Haberl+, 2016)
J/ApJ/817/113 : RIOTS4: spectroscopic survey SMC field OB stars (Lamb+, 2016)
J/AcA/66/421 : Eclipsing binaries in the Magellanic System (Pawlak+, 2016)
J/ApJ/867/L8 : Gaia kinematic data runaway & field OB stars SMC (Oey+, 2018)
J/A+A/625/A104 : Stellar parameters OB stars in SMC wing (Ramachandran+, 2019)
J/A+A/624/A66 : Massive runaway and walkaway stars models (Renzo+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID [107/84544] Massey, 2002 II/236 identifier
(<M2002 SMC NNNNN> in Simbad)
7- 24 A18 --- SpType MK spectral type (1)
26- 32 A7 --- Subgroup Subgroup classifier (2)
34- 36 I3 km/s vloc [2/260] Local residual transverse velocity
from Oey+, 2018, J/ApJ/867/L8
38- 39 I2 km/s e_vloc [11/47] Error on vloc
41- 44 F4.1 Msun Mass [9.5/61.4]? Stellar mass
46- 48 A3 --- f_Mass Flag on M (3)
50- 53 F4.1 Msun e_Mass [0.7/26.5]? Error on M (4)
55- 55 A1 --- l_vsini Limit flag on vsini (5)
56- 58 I3 km/s vsini [43/439]? Projected rotational velocity (5)
60- 61 I2 km/s e_vsini [2/50]? Error on vsini
63- 66 F4.1 kK Teff [12.0/49.3]? Effective temperature
68- 71 F4.1 kK e_Teff [1.2/10.8]? Error on Teff
73- 76 F4.2 [Lsun] logL [4.09/6.03]? Log luminosity
78- 81 F4.2 [Lsun] e_logL [0.04/0.42]? Error on logL
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Note (1): Spectral types for the four B[e] stars (M2002-29267, 46398, 62661,
83480) are taken from Graus+, 2012ApJ...759...10G 2012ApJ...759...10G. The rest are from
Lamb+, 2016, J/ApJ/817/113.
Note (2): Subgroup type as follows:
E = Eclipsing binary (EB);
S = Double-lined spectroscopic binary (SB2);
X = High-mass X-ray binary (HMXB);
e = Oe or Be star.
Note (3): Flags as follows:
: = uncertain stellar mass estimate (see Section 3.1);
n = one of the following: The mass for SMC X-1 (M2002-77458) is taken
from Rawls+, 2011ApJ...730...25R 2011ApJ...730...25R, and those for M2002-38024 and 59319
are taken from Lamb+, 2013, J/ApJ/763/101. For the mass of the 'mid'
Oe star M2002-73795 we calculated the average Teff from adopting O5e
and O7e spectral types, and for the Oe star M2002-75689 we adopted O3e
and O9e spectral types. For the 'O + B' binaries (M2002-11238, 22178,
66160) we calculated the average Teff from adopting O3 and O9 spectral
types, in estimating masses.
Note (4): Error on mass for stars flagged with ':' is computed from the
upper/lower limits on the mass range (see Section 3.1). The mass errors
for M2002-38024 and 59319 are '+1.6/-3.6' and '+5.3/-4.7', respectively,
taken from Lamb et al. (2013ApJ...763..101L 2013ApJ...763..101L), J/ApJ/763/101.
Note (5): '<' indicates vsini measurement for SB2 is an upper limit.
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History:
From electronic version of the journal
References:
Oey et al. Paper I: 2018ApJ...867L...8O 2018ApJ...867L...8O Cat. J/ApJ/867/L8
(End) Prepared by [AAS], Coralie Fix [CDS], 28-Jan-2022