J/A+A/624/A66 Massive runaway and walkaway stars models (Renzo+, 2019)
Massive runaway and walkaway stars. A study of the kinematical imprints of the
physical processes governing the evolution and explosion of their binary
progenitors.
Renzo M., Zapartas E., de Mink S.E., Goetberg Y., Justham S., Farmer R.J.,
Izzard R.G., Toonen S., Sana H.
<Astron. Astrophys. 624, A66 (2019)>
=2019A&A...624A..66R 2019A&A...624A..66R (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Supernovae ; Stars, double and multiple
Keywords: astrometry - binaries: close - stars: evolution -
stars: kinematics and dynamics - stars: massive - supernovae: general
Abstract:
We perform an extensive numerical study of the evolution of massive
binary systems to predict the peculiar velocities that stars obtain
when their companion collapses and disrupts the system. Our aim is to
(i) identify which predictions are robust against model uncertainties
and assess their implications, (ii) investigate which physical
processes leave a clear imprint and may, therefore, be constrained
observationally and (iii) provide a suite of publicly available model
predictions, to allow for the use of kinematic constraints from the
Gaia mission. We find that 22+26-8% of all massive binary systems
merge prior to the first core-collapse in the system. Of the
remainder, 86+11-9% become unbound because of the core-collapse.
Remarkably, this rarely produce runaway stars (observationally defined
as stars with velocities above 30km/s). These are outnumbered by
more than an order of magnitude by slower unbound companions, or
"walkaway stars". This is a robust outcome of our simulations and
is due to the reversal of the mass ratio prior to the explosion and
widening of the orbit, as we show analytically and numerically. For
stars more massive than 15M☉, we estimate that 10+5-8% are
walkaways and only 0.5+1.0-0.4% are runaways, nearly all of which
have accreted mass from their companion. Our findings are consistent
with earlier studies, however, the low runaway fraction we find is in
tension with observed fractions of about 10%. Thus, astrometric data
on presently single massive stars can potentially constrain the
physics of massive binary evolution. Finally, we show that the high
end of the mass distributions of runaway stars is very sensitive to
the assumed black hole natal kicks and propose this as a potentially
stringent test for the explosion mechanism. We also discuss companions
remaining bound which can evolve into X-ray and gravitational wave
sources.
Description:
Each file contains the output of our population synthesis simulations
(see Table 1). The data files include both systems remaining bound and
those that are disrupted. Each system is logged at the time of the
first SN and we store initial values of masses and period, the
pre-cor-collapse and post-core collapse masses, period, eccentricity,
separation, and information on the explosion (kick amplitude and
direction, fallback fraction) and the pre-CC and post-CC orbital and
kinematic properties. We also provide the time each system spends in
phases with at least one of the two stars on the main sequence.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 222 37 Outcome of our model variations
files/* . 39 Individual output files
(corrected files, 13-Nov-2020)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 60 A60 --- Assump Physical assumption
61- 87 A27 --- Param Parameter
89-110 A22 ---- Value Value of parameter
112-114 I3 pc Average distance traveled from the ejection
to CC for all massive companions ejected
116-118 I3 pc <Lrun> ?=- Average distance traveled from the
ejection to CC for massive runaways only
120-122 I3 pc <Lwalk> Average distance traveled from the ejection
to CC for massive walkaways only
124-127 F4.1 km/s Average velocity
129-132 F4.1 km/s vmed Median velocity
134-137 F4.1 Msun Average mass for ejected main sequence
companions
139-142 F4.1 Msun <M2run> ?=- Average mass for ejected main sequence
companions for runaways only,
144-147 F4.1 Msun <M2walk> Average mass for ejected main sequence
companions for walkaways only
149-152 F4.1 --- RMS ?=- Produced ratio R of walkaways to
runaways for all masses
154-157 F4.1 --- R7.5 ?=- Produced ratio R of walkaways to
runaways above 7.5Msun
159-162 F4.1 --- R15 ?=- Produced ratio R of walkaways to
runaways above 15Msun
164-167 F4.2 --- M Fraction of all the binaries simulated
resulting in a merger
169-172 F4.2 --- D Disruption fraction among the non-merging
binaries
174-176 F3.1 % f15RW ?=- Fraction of runaways with masses larger
than 15Msun
178-181 F4.1 % f15WA ?=- Fraction of walkaways with masses larger
than 15Msun
183-224 A42 ---- FileName Name of the output file in subdirectory files
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Description of file: files/*
Hearder of 48 lines, followed by parameters separated by tabulations
-------------------------------------------------------------------------------
Col Format Units Label Explanations
-------------------------------------------------------------------------------
1 F22.12 Msun M1zams Zero age main sequence mass of
star 1
2 F22.12 Msun M1preCC Pre-core-collapse mass of star 1
3 F22.12 Msun M1postCC Post-core-collapse mass of star 1
4 F22.12 ---- fb1 Fallback fraction for star 1
5 F22.12 ---- type1preCC Stellar type before core-collapse
for star 1
6 F22.12 ---- type1postCC Stellar type after core-collapse
for star 1
7 F22.12 km/s v1postCC Speed of star 1 after
core-collapse
8 F22.12 Msun M2zams Zero age main sequence mass of
star 2
9 F22.12 Msun M2preCC Pre-core-collapse mass of star 2
10 F22.12 Msun M2postCC Post-core-collapse mass of star 2
11 F22.12 ---- fb2 Fallback fraction for star 2
12 F22.12 ---- type2preCC Stellar type before core-collapse
for star 2
13 F22.12 ---- type2postCC Stellar type after core-collapse
for star 2
14 F22.12 km/s v2postCC Speed of star 2 after
core-collapse
15 F22.12 ---- epreCC Eccentricity before core-collapse
(-1 or >0 if disrupted)
16 F22.12 ---- epostCC Eccentricity after core-collapse
(-1 or >0 if disrupted)
17 F22.12 Rsun apreCC Orbital semi-major axis before
core-collapse
18 F22.12 Rsun apostCC Orbital semi-major axis after
core-collapse
19 F22.12 d Pzams Zero age main sequence period
20 F22.12 d PpreCC Pre-core-collapse period
21 F22.12 d PpostCC Post-core-collapse period
22 F22.12 km/s vkick SN natal kick amplitude
23 F22.12 ---- theta SN kick angle (see Tauris & Takens
1998A&A...330.1047T 1998A&A...330.1047T)
24 F22.12 ---- phi SN kick angle (see Tauris & Takens
1998A&A...330.1047T 1998A&A...330.1047T)
25 F22.12 km/s vsys Systemic post-core-collapse
velocity
26 F22.12 Myr texplosion Age of the system at the first
core-collapse
27 F22.12 Myr tremaining Time remaining for the non-compact
object in the current evolutionary
phase after the core-collapse
28 F22.12 ---- Prob System probablity
29 F22.12 Myr tMS-MS Time spent by the binary as two
main sequence stars
30 F22.12 Myr tMS-star Time spent as one main sequence star
with a non-compact companion
31 F22.12 Myr tMS-comp Time spent as one main sequence star
with a compact companion
32 F22.12 Myr tMS-merger Time spent as main sequence merger
product
33 F22.12 Myr tMS-ejected Time spent as disrupted binary with
one ejected star on the
main sequence
34 F22.12 Myr tMS-MS-massive Time spent by the binary as two main
sequence stars and at least one is
more massive than 7.5Msun
35 F22.12 Myr tMS-star-massive Time spent as one main sequence star
with mass greater than 7.5Msun and
a non-compact companion
36 F22.12 Myr tMS-comp-massive Time spent as one main sequence star
with mass greater than 7.5Msun with
a compact companion
37 F22.12 Myr tMS-merger-massive Time spent as main sequence merger
product with mass greater
than 7.5Msun
38 F22.12 Myr tMS-ejected-massive Time spent as disrupted binary with
one ejected star on the main
sequence and mass greater
than 7.5Msun
39 F22.12 Myr tMS-MS-Otype Time spent by the binary as two main
sequence stars and at least one is
more Otype than 15Msun
40 F22.12 Myr tMS-star-Otype Time spent as one main sequence star
with mass greater than 15Msun and
a non-compact companion
41 F22.12 Myr tMS-comp-Otype Time spent as one main sequence star
with mass greater than 15Msun with
a compact companion
42 F22.12 Myr tMS-merger-Otype Time spent as main sequence merger
product with mass greater
than 15Msun
43 F22.12 Myr tMS-ejected-Otype Time spent as disrupted binary with
one ejected star on the main
sequence and mass greater
than 15Msun
-------------------------------------------------------------------------------
Acknowledgements:
Mathieu Renzo, m.renzo(at)uva.nl
History:
11-Apr-2019: on-line version
13-Nov-2020: corrected files in files from author
(End) Patricia Vannier [CDS] 08-Mar-2019