J/A+A/558/A103 Stellar models with rotation. 0.8<M<120, Z=0.002 (Georgy+, 2013)
Grids of stellar models with rotation.
III. Models from 0.8 to 120 Msun at a metallicity Z = 0.002.
Georgy C., Ekstrom S., Eggenberger P., Meynet G., Haemmerle L.,
Maeder A., Granada A., Groh J.H., Hirschi R., Mowlavi N.,
Yusof N., Charbonnel C., Decressin T., Barblan F.
<Astron. Astrophys. 558, A103 (2013)>
=2013A&A...558A.103G 2013A&A...558A.103G
ADC_Keywords: Models, evolutionary ; Mass loss ; Stars, supergiant ;
Magellanic Clouds
Keywords: stars: general - stars: evolution - stars: rotation - stars: massive -
stars:low-mass
Abstract:
We study the impact of a subsolar metallicity on various properties of
non-rotating and rotating stars, such as surface velocities and
abundances, lifetimes, evolutionary tracks, and evolutionary
scenarios. We provide a grid of single star models covering a mass
range of 0.8 to 120M{sun} with an initial metallicity Z=0.002 with
and without rotation. We discuss the impact of a change in the
metallicity by comparing the current tracks with models computed with
exactly the same physical ingredients but with a metallicity Z=0.014
(solar).
We show that the width of the main-sequence (MS) band in the upper
part of the Hertzsprung-Russell diagram (HRD), for luminosity above
log(L/L☉)>5.5, is very sensitive to rotational mixing. Strong
mixing significantly reduces the MS width. Here for the first time
over the whole mass range, we confirm that surface enrichments are
stronger at low metallicity provided that comparisons are made for
equivalent initial mass, rotation, and evolutionary stage. We show
that the enhancement factor due to a lowering of the metallicity (all
other factors kept constant) increases when the initial mass
decreases. Present models predict an upper luminosity for the red
supergiants (RSG) of log (L/L☉) around 5.5 at Z=0.002 in
agreement with the observed upper limit of RSG in the Small Magellanic
Cloud. We show that models using shear diffusion coefficient, which is
calibrated to reproduce the surface enrichments observed for MS B-type
stars at Z=0.014, can also reproduce the stronger enrichments observed
at low metallicity. In the framework of the present models, we discuss
the factors governing the timescale of the first crossing of the
Hertzsprung gap after the MS phase. We show that any process favouring
a deep localisation of the H-burning shell (steep gradient at the
border of the H-burning convective core, low CNO content), and/or the
low opacity of the H-rich envelope favour a blue position in the HRD
for the whole, or at least a significant fraction, of the core
He-burning phase.
Description:
Data of the 24 non-rotating and 24 rotating models.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tables.dat 569 19200 Evolutionary tracks
files.tar 1274 19200 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, Paper I.
(Ekstrom+, 2012)
J/A+A/543/A108 : Grid of stellar models, asteroseismology (Lagarde+, 2012)
Byte-by-byte Description of file: tables.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 Msun Mini [0.8/120] Initial mass
8- 12 F5.3 --- Zini [0.002] Initial metallicity
14 A1 --- Rot [nr] r for rotation, n for no rotation
16- 18 I3 --- Line [1/400] Number of selected point
20- 41 E22.15 yr Time Age
43- 53 F11.6 Msun Mass Actual mass
54- 63 F10.6 [Lsun] logL Luminosity in log scale
65- 73 F9.6 [K] logTe Effective temperature in log scale
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 Uncorrected effective temperature
in log scale (WR stars only)
254-261 F8.3 [Msun/yr] logdM/dt Mass loss rate in log scale
263-271 F9.6 [g/cm3] log(rhoc) Central density in log scale
273-281 F9.6 [K] logTc Central temperature in log scale
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 rad/s Omegas Surface angular velocity Ωs
455-464 E10.3 rad/s Omegac Central angular velocity Ωc
466-475 E10.3 --- oblat [0/1] Oblateness (Rpol/Req)
477-486 E10.3 --- dM/dtR Rotational dM/dt correction factor
488-496 E9.2 km/s vcrit1 First critical velocity (Ω-limit)
498-506 E9.2 km/s vcrit2 Second critical velocity
(ΩΓ-limit)
508-516 E9.2 km/s veq Equatorial velocity
518-526 F9.6 --- OOc [0/1] Ωsurf/Ωcrit
528-536 F9.6 --- Gedd [0/1] Eddington factor Γ
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:
Cyril Georgy, c.georgy(at)keele.ac.uk
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
(End) Cyril Georgy [Keele Univ.], Patricia Vannier [CDS] 26-Aug-2013