J/A+A/627/A24 Stellar models with rotation. 1.7<M<120, Z=0.0004 (Groh+, 2019)
Grids of stellar models with rotation.
IV. Models from 1.7 to 120 M☉ at a metallicity Z = 0.0004.
Groh J.H., Ekstrom S., Georgy C., Meynet G., Choplin A., Eggenberger P.,
Hirschi R., Maeder A., Murphy L.J., Boian I., Farrell E.J.
<Astron. Astrophys. 627, A24 (2019)>
=2019A&A...627A..24G 2019A&A...627A..24G (SIMBAD/NED BibCode)
ADC_Keywords: Models, evolutionary ; Mass loss ; Abundances
Keywords: stars: evolution - stars: rotation - stars: massive -
stars: fundamental parameters - stars: mass-loss - stars: abundances
Abstract:
The effects of rotation on stellar evolution are particularly
important at low metallicity, when mass loss by stellar winds
diminishes and the surface enrichment due to rotational mixing becomes
relatively more pronounced than at high metallicities. Here we
investigate the impact of rotation and metallicity on stellar
evolution. Using a similar physics as in our previous large grids of
models at Z=0.002 and Z=0.014, we compute stellar evolution models
with the Geneva code for rotating and non-rotating stars with initial
masses (Mini) between 1.7 and 120M☉ and Z=0.0004 (1/35 solar).
This is comparable to the metallicities of the most metal poor
galaxies observed so far, such as I Zw 18. Concerning massive stars,
both rotating and non-rotating models spend most of their core-helium
burning phase with an effective temperature higher than 8000K. Stars
become red supergiants only at the end of their lifetimes, and few
RSGs are expected. Our models predict very few to no classical
Wolf-Rayet stars as a results of weak stellar winds at low
metallicity. The most massive stars end their lifetimes as luminous
blue supergiants or luminous blue variables, a feature that is not
predicted by models with higher metallicities. Interestingly, due to
the behavior of the intermediate convective zone, the mass domain of
stars producing pair-instability supernovae is smaller at Z=0.0004
than at Z=0.002. We find that during the main sequence phase, the
ratio between nitrogen and carbon abundances (N/C) remains unchanged
for non-rotating models. However, N/C increases by factors of 10-20 in
rotating models at the end of the MS. Cepheids coming from stars with
Mini>4-6M☉ are beyond the core helium burning phase and spend
little time in the instability strip. Since they would evolve towards
cooler effective temperatures, these Cepheids should show an increase
of the pulsation period as a function of age.
Description:
Here we present a grid of rotating and nonrotating stellar evolution
models computed with the Geneva code, for the initial mass range
1.7-120 M☉ and metallicity Z=0.0004.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables.dat 569 13600 Evolutionary tracks
files.tar 1274 13600 All the individual files for the 48 stellar tracks
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See also:
J/A+A/537/A146 : Stellar models with rotation. 0.8<M<120, Z=0.014
(Ekstrom+, 2012)
J/A+A/558/A103 : Stellar models with rotation. 0.8<M<120, Z=0.002
(Georgy+, 2014)
Byte-by-byte Description of file: tables.dat
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Bytes Format Units Label Explanations
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1- 5 F5.1 Msun Mini [0.8/120] Initial mass
7- 12 F6.4 --- Zini [0.0004] Initial metallicity
14 A1 --- Rot [nr] r for rotation, n for no rotation
16- 18 I3 --- Line Number of selected point
20- 41 E22.15 yr Time Age
43- 53 F11.6 Msun Mass Actual mass in solar masses
54- 63 F10.6 Lsun logL log(luminosity) in solar units
65- 73 F9.6 [K] logTe log(effective temperature)
75- 88 E14.7 --- X H surface abundance (mass fraction)
90-103 E14.7 --- Y He surface abundance (mass fraction)
105-118 E14.7 --- C12 12C surface abundance (mass fraction)
120-133 E14.7 --- C13 13C surface abundance (mass fraction)
135-148 E14.7 --- N14 14N surface abundance (mass fraction)
150-163 E14.7 --- O16 16O surface abundance (mass fraction)
165-178 E14.7 --- O17 17O surface abundance (mass fraction)
180-193 E14.7 --- O18 18O surface abundance (mass fraction)
195-208 E14.7 --- Ne20 20Ne surface abundance
(mass fraction)
210-223 E14.7 --- Ne22 22Ne surface abundance
(mass fraction)
225-234 E10.3 --- Al26 26Al surface abundance
(mass fraction)
236-242 F7.4 --- QCC Convective core mass fraction
244-252 F9.6 [K] logTe.u log(uncorrected Teff) (WR stars only)
254-261 F8.3 [Msun/yr] logdM/dt log(mass loss rate)
263-271 F9.6 [g/cm3] log(rhoc) log(central density)
273-281 F9.6 [K] logTc log(central temperature)
283-296 E14.7 --- Xc H central abundance (mass fraction)
298-311 E14.7 --- Yc 4He central abundance (mass fraction)
313-326 E14.7 --- C12c 12C central abundance (mass fraction)
328-341 E14.7 --- C13c 13C central abundance (mass fraction)
343-356 E14.7 --- N14c 14N central abundance (mass fraction)
358-371 E14.7 --- O16c 16O central abundance (mass fraction)
373-386 E14.7 --- O17c 17O central abundance (mass fraction)
388-401 E14.7 --- O18c 18O central abundance (mass fraction)
403-416 E14.7 --- Ne20c 20Ne central abundance
(mass fraction)
418-431 E14.7 --- Ne22c 22Ne central abundance
(mass fraction)
433-442 E10.3 --- Al26c 26Al central abundance
(mass fraction)
444-453 E10.3 s-1 Omegas Surface angular velocity
455-464 E10.3 s-1 Omegac Central angular velocity
466-475 E10.3 --- oblat Oblateness, Rp/Re
477-486 E10.3 --- dM/dtR Rotational Mdot correction factor
488-496 E9.2 km/s vcrit1 First critical velocity (Omega-limit)
498-506 E9.2 km/s vcrit2 Second critical velocity
(OmegaGamma-limit)
508-516 E9.2 km/s veq Equatorial velocity
518-526 F9.6 --- OOc Omegasurf/Omegacrit
528-536 F9.6 --- Gedd Eddington factor
538-551 E14.7 Msun/yr dM/dtm Mechanical equatorial dM/dt
553-569 E17.10 10+53g.cm2/s Ltot Total angular momentum
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Acknowledgements:
Sylvia Ekstrom, Sylvia.Ekstrom(at)unige.ch
References:
Ekstrom et al,. Paper I 2012A&A...537A.146E 2012A&A...537A.146E, Cat. J/A+A/537/A146
Georgy et al., Paper II 2012A&A...542A..29G 2012A&A...542A..29G
Georgy et al., Paper III 2013A&A...558A.103G 2013A&A...558A.103G, Cat. J/A+A/558/A103
(End) Sylvia Ekstrom [Geneva Obs], Patricia Vannier [CDS] 12-Apr-2019