J/A+A/637/A6 Stripped-envelope stars Binary Evolution Models (Laplace+, 2020)
The expansion of stripped-envelope stars:
Consequences for supernovae and gravitational-wave progenitors.
Laplace E., Goetberg Y., de Mink S.E., Justham S., Farmer R.
<Astron. Astrophys. 637, A6 (2020)>
=2020A&A...637A...6L 2020A&A...637A...6L (SIMBAD/NED BibCode)
ADC_Keywords: Models, evolutionary ; Stars, double and multiple ;
Stars, Wolf-Rayet
Keywords: binaries: close - gravitational waves - stars: massive -
stars: evolution - stars: Wolf-Rayet - supernovae: general
Abstract:
Massive binaries that merge as compact objects are the progenitors of
gravitational-wave sources. Most of these binaries experience one or
more phases of mass transfer, during which one of the stars loses part
or all of its outer envelope and becomes a stripped-envelope star. The
evolution of the size of these stripped stars is crucial in
determining whether they experience further interactions and their
final fate. We present new calculations of stripped-envelope stars
based on binary evolution models computed with the MESA stellar
evolution code. We use these to investigate their radius evolution as
a function of mass and metallicity. We further discuss their pre-
supernova observable characteristics and potential consequences of
their evolution on the properties of supernovae from stripped stars.
At high metallicity we find that practically all of the hydrogen-rich
envelope is removed, in agreement with earlier findings. Only
progenitors with initial masses below 10\Msun expand to large radii
(up to 100R☉), while more massive progenitors stay compact. At low
metallicity, a substantial amount of hydrogen remains and the
progenitors can, in principle, expand to giant sizes (>400R☉),
for all masses we consider. This implies that they can fill their
Roche lobe anew. We show that the prescriptions commonly used in
population synthesis models underestimate the stellar radii by up to
two orders of magnitude. We expect that this has consequences for the
predictions for gravitational-wave sources from double neutron star
mergers, in particular for their metallicity dependence.
Description:
We have modelled the evolution of the initially more massive stars in
binary systems at solar (z1=0.0142) and sub-solar (z2=0.001)
metallicity with initial masses ranging from 8.86 to 15.0 solar masses
with the MESA stellar evolution code. The initial orbital period is
25d for all models, and the mass ratio is 0.8. We assumed conservative
mass transfer. After core helium depletion (grid_b), we treat the
stars as single stars. This allows us to probe the maximum radius they
can achieve. This dataset contains the stellar evolution models, that
is, the detailed time evolution of key physical parameters discussed
in the article.
Each model is labelled zZ_mM.data, where Z stands for the initial
metallicity and M for the initial mass.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 175 92 List of files
grid_a/* . 46 *All evolutionary models from zero age
main-sequence until core helium depletion
grid_b/* . 46 *All evolutionary models from from core helium
depletion until core carbon depletion
--------------------------------------------------------------------------------
Note on grid_a/*, grid_b/*: All units are in CGS unless otherwise specified.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 A20 --- FileName Name of the file
23- 28 F6.4 --- Z [0.001/0.0142] Initial metallicity
30- 34 F5.2 Msun Mini Initial mass
36-175 A140 --- Title Title
--------------------------------------------------------------------------------
Byte-by-byte Description of file (#): grid_a/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
-------------------------------------------------------------------------------
1- 24 E24.19 --- Model MESA model number count form the
start of the calculation
(model_number)
33- 57 E25.19 --- Nzones Number of zones computed
(num_zones)
65- 89 E25.19 yr Age Star age (star_age)
97- 121 E25.19 [yr] logdt Time step (log_dt)
129- 153 E25.19 Msun Mass Star mass (star_mass)
161- 185 E25.19 [g] log(xMass) Mass exterior to the central
mass (log_xmstar)
193- 217 E25.19 [Msun/yr] log(absMdot) Absolute value of mass lost from
the star (logabsmdot)
225- 249 E25.19 [Lsun] logLH Hydrogen-burning luminosity
(log_LH)
257- 281 E25.19 [Lsun] logLHe Helium-burning luminosity
(log_LHe)
289- 313 E25.19 [Lsun] logLZ Metal-burning luminosity
(log_LZ)
321- 345 E25.19 [Lsun] logLnuc Total nuclear burning luminosity
(log_Lnuc)
353- 377 E25.19 [Lsun] pp Total luminosity from the
pp-chain reaction (pp)
385- 409 E25.19 [Lsun] cno Total luminosity from the
CNO-cycle (cno)
417- 441 E25.19 [Lsun] tri_alfa Total luminosity from the
triple-alpha reaction
(tri_alfa)
449- 473 E25.19 Msun HeCoreMass Helium core mass (hecoremass)
481- 505 E25.19 Msun CCoreMass Carbon core mass (ccoremass)
513- 537 E25.19 Msun OCoreMass Oxygen core mass (ocoremass)
545- 569 E25.19 Msun SiCoreMass Silicon core mass (sicoremass)
577- 601 E25.19 Msun FeCoreMass Iron core mass (fecoremass)
609- 633 E25.19 Msun nrichCoreMass Neutron-rich core mass
(neutronrichcore_mass)
641- 665 E25.19 [K] logTeff Effective temperature (log_Teff)
673- 697 E25.19 [Lsun] logL Total stellar luminosity (log_L)
705- 729 E25.19 [Rsun] logR Stellar radius (log_R)
737- 761 E25.19 [cm/s2] logg Surface gravity (log_g)
769- 793 E25.19 [K] logcenterT Central temperature
(logcenterT)
801- 825 E25.19 [g/cm3] logcenterRho Central density (logcenterRho)
833- 857 E25.19 --- centermu Central mean molecular weight
per gas particle (center_mu)
865- 889 E25.19 --- centerye Central fraction of electrons
per baryon (center_ye)
897- 921 E25.19 g/mol centerabar Central average atomic weight
(center_abar)
929- 953 E25.19 --- centerH1 Central hydrogen fraction
(center_h1)
961- 985 E25.19 --- centerHe4 Central helium fraction
(center_he4)
993-1017 E25.19 --- centerC12 Central Carbon fraction
(center_c12)
1025-1049 E25.19 --- centerO16 Central Oxygen fraction
(center_o16)
1057-1081 E25.19 --- surfaceC12 Surface Carbon fraction
(surface_c12)
1089-1113 E25.19 --- surfaceO16 Surface Oxygen fraction
(surface_o16)
1121-1145 E25.19 Msun H1MassTot Total hydrogen mass
(totalmassh1)
1153-1177 E25.19 Msun He4MassTot Total helium mass
(totalmasshe4)
1185-1209 E25.19 d Per Binary orbital period
(period_days)
1217-1241 E25.19 Rsun sep Binary orbital separation
(binary_separation)
1249-1273 E25.19 km/s Vorb1 Orbital velocity of the primary
star (vorb1)
1281-1305 E25.19 km/s Vorb2 Orbital velocity of the
secondary star (vorb2)
1313-1337 E25.19 Rsun rl1 Roche lobe radius of the primary
star (rl_1)
1345-1369 E25.19 Rsun rl2 Roche lobe radius of the
secondary star (rl_2)
1377-1401 E25.19 --- rlrelover1 Roche lobe overflow of primary
star in units of rl_1
(rlrelativeoverflow_1)
1409-1433 E25.19 --- rlrelover2 Roche lobe overflow of secondary
star in units of rl_1
(rlrelativeoverflow_2)
1441-1465 E25.19 Msun Mass2 Secondary star mass
(star2mass)
1473-1497 E25.19 [Msun/yr] log(MTransRate) Mass-transfer rate
(lgmtransferrate)
1505-1529 E25.19 --- XferFract Mass-transfer fraction
(xfer_fraction)
1537-1561 E25.19 g.cm2/s Jorb Orbital angular momentum (J_orb)
1569-1593 E25.19 g.cm2/s/yr Jdot Time derivative of the orbital
angular momentum (Jdot)
--------------------------------------------------------------------------------
Byte-by-byte Description of file (#): grid_a/* grid_b/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
-------------------------------------------------------------------------------
1- 25 E25.19 --- Model MESA model number count form the
start of the calculation
(model_number)
33- 57 E25.19 --- Nzones Number of zones computed
(num_zones)
65- 89 E25.19 yr Age Star age (star_age)
97- 121 E25.19 [yr] logdt Time step (log_dt)
129- 153 E25.19 Msun Mass Star mass (star_mass)
161- 185 E25.19 [g] log(xMass) Mass exterior to the central
mass (log_xmstar)
193- 217 E25.19 [Msun/yr] log(absMdot) Absolute value of mass lost from
the star (logabsmdot)
225- 249 E25.19 [Lsun] logLH Hydrogen-burning luminosity
(log_LH)
257- 281 E25.19 [Lsun] logLHe Helium-burning luminosity
(log_LHe)
289- 313 E25.19 [Lsun] logLZ Metal-burning luminosity
(log_LZ)
321- 345 E25.19 [Lsun] logLnuc Total nuclear burning luminosity
(log_Lnuc)
353- 377 E25.19 [Lsun] pp Total luminosity from the
pp-chain reaction (pp)
385- 409 E25.19 [Lsun] cno Total luminosity from the
CNO-cycle (cno)
417- 441 E25.19 [Lsun] tri_alfa Total luminosity from the
triple-alpha reaction
(tri_alfa)
449- 473 E25.19 Msun HeCoreMass Helium core mass (hecoremass)
481- 505 E25.19 Msun CCoreMass Carbon core mass (ccoremass)
513- 537 E25.19 Msun OCoreMass Oxygen core mass (ocoremass)
545- 569 E25.19 Msun SiCoreMass Silicon core mass (sicoremass)
577- 601 E25.19 Msun FeCoreMass Iron core mass (fecoremass)
609- 633 E25.19 Msun nrichCoreMass Neutron-rich core mass
(neutronrichcore_mass)
641- 665 E25.19 [K] logTeff Effective temperature (log_Teff)
673- 697 E25.19 [Lsun] logL Total stellar luminosity (log_L)
705- 729 E25.19 [Rsun] logR Stellar radius (log_R)
737- 761 E25.19 [cm/s2] logg Surface gravity (log_g)
769- 793 E25.19 [K] logcenterT Central temperature
(logcenterT)
801- 825 E25.19 [g/cm3] logcenterRho Central density (logcenterRho)
833- 857 E25.19 --- centermu Central mean molecular weight
per gas particle (center_mu)
865- 889 E25.19 --- centerye Central fraction of electrons
per baryon (center_ye)
897- 921 E25.19 g/mol centerabar Central average atomic weight
(center_abar)
929- 953 E25.19 --- centerH1 Central hydrogen fraction
(center_h1)
961- 985 E25.19 --- centerHe4 Central helium fraction
(center_he4)
993-1017 E25.19 --- centerC12 Central Carbon fraction
(center_c12)
1025-1049 E25.19 --- centerO16 Central Oxygen fraction
(center_o16)
1057-1081 E25.19 --- surfaceC12 Surface Carbon fraction
(surface_c12)
1089-1113 E25.19 --- surfaceO16 Surface Oxygen fraction
(surface_o16)
1121-1145 E25.19 Msun H1MassTot Total hydrogen mass
(totalmassh1)
1153-1177 E25.19 Msun He4MassTot Total helium mass
(totalmasshe4)
--------------------------------------------------------------------------------
Acknowledgements:
Eva Laplace, e.c.laplace(at)uva.nl
References:
Paxton et al., 2011ApJS..192....3P 2011ApJS..192....3P
Paxton et al., 2013ApJS..208....4P 2013ApJS..208....4P
Paxton et al., 2015ApJS..220...15P 2015ApJS..220...15P
Paxton et al., 2018ApJS..234...34P 2018ApJS..234...34P
Paxton et al., 2019ApJS..243...10P 2019ApJS..243...10P
(End) Eva Laplace [API, UvA], Patricia Vannier [CDS] 23-Apr-2020