J/A+A/580/A27 Asteroseismology of KIC 10526294 (Moravveji+, 2015)
Tight asteroseismic constraints on core overshooting and diffusive mixing in
the slowly rotating pulsating B8.3V star KIC 10526294.
Moravveji E., Aerts C., Papics P.I., Triana S.A., Vandoren B.
<Astron. Astrophys. 580, A27 (2015)>
=2015A&A...580A..27M 2015A&A...580A..27M
ADC_Keywords: Stars, B-type
Keywords: asteroseismology - stars: oscillations - stars: interiors -
stars: evolution - stars: individual: KIC 10526294 - opacity
Abstract:
KIC 10526294 is a very slowly rotating and slowly pulsating late
B-type star. Its 19 consecutive dipole gravity modes constitute a
series with almost constant period spacing. This unique collection of
identified modes probes the near-core environment of this star and
holds the potential to reveal the size and structure of the
overshooting zone on top of the convective core, as well as the mixing
properties of the star. We pursue forward seismic modelling based on
adiabatic eigenfrequencies of equilibrium models for eight extensive
evolutionary grids tuned to KIC 10526294, by varying the initial mass,
metallicity, chemical mixture, and the extent of the overshooting
layer on top of the convective core. We examine models for both OP and
OPAL opacities and test the occurrence of extra diffusive mixing. We
find a tight mass, metallicity relation within the ranges M∼3.13 to
3.25M☉ and Z∼0.014 to 0.028. We deduce that an exponentially
decaying diffusive core overshooting prescription describes the
seismic data better than a step function formulation and derive a
value of f_ov between 0.017 and 0.018. Moreover, the inclusion of
extra diffusive mixing with a value of log D_mix between 1.75 and
2.00dex (with Dmix in cm2/sec) improves the goodness-of-fit based on
the observed and modelled frequencies with a factor 11 compared to the
case where no extra mixing is considered, irrespective of the (M,Z)
combination within the allowed seismic range. The inclusion of
diffusive mixing in addition to core overshooting is essential to
explain the structure in the observed period spacing pattern of this
star. Moreover, we deduce that an exponentially decaying prescription
for the core overshooting is to be preferred over a step function. Our
best models for KIC 10526294 approach the seismic data to a level that
they can serve future inversion of its stellar structure.
Description:
All required inputs to reproduce all our results are presented. These
should be coupled to MESA version 5548, and GYRE version 3.0. The best
models for Model 4, 5, 8, 10 and 11 (based on Table 3) are also
included; they are all compatible with GYRE. The opacity archive is
fully MESA compatible, and should not be extracted, unless in MESA
directory, and by MESA itself.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 74 11 Compilation of best models from different grids
(Table 2) and their input parameters
head.dat 76 5 Headers of model files
model4.dat 492 5372 GYRE input for Model 4 in Table 3
model5.dat 492 5366 GYRE input for Model 5 in Table 3
model8.dat 492 5371 GYRE input for Model 8 in Table 3
model10.dat 492 5491 GYRE input for Model 10 in Table 3
model11.dat 492 5375 GYRE input for Model 11 in Table 3
readme.txt 78 41 Informations on files in files subdirectory
files/* . 5 Fortran and input files, and
tarball to be extracted by MESA
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Model [1/11] Model number
4- 17 A14 --- Grid Type of grid used
19- 22 A4 --- Opacity Opacity table used (OP or OPAL)
24- 29 A6 --- Mixture Mixture used (NP12, A09, A05+Ne) (1)
31- 34 F4.2 Msun Mass [3.1/3.5] Mass
36- 39 F4.2 --- Xini [0.69/0.71] Initial X abundance
41- 45 F5.3 --- Zini [0.01/0.028] Initial Z abundance
47- 51 F5.3 --- Xc [0.25/0.7] Centre hydrogen abundance
53- 57 F5.3 --- fov [0/0.21] Overshooting parameter for all models
except for Model 10 where we list αov
59- 62 F4.2 [cm2/s] logDmix [1.75/2]?=- Extra diffusive mixing
64- 68 I5 --- chi2r [1711/23200] Reduced χ2 value
70- 74 F5.2 --- chi2P [1.4/23] χ2 value from Papics et al.
(2014A&A...570A...8P 2014A&A...570A...8P)
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Note (1): Values are from:
NP12 = Nieva and Przybilla 2012 (J/A+A/539/A143);
Przybilla et al. 2013, in EAS Publications Series 63, 13-23.
A09 = Asplund et al. 2009ARA&A..47..481A 2009ARA&A..47..481A
A05+Ne = Asplund et al. (2005ASPC..336...25A 2005ASPC..336...25A), mixture with a Ne enhancement
based on Cunha et al. (2006ApJ...647L.143C 2006ApJ...647L.143C)
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Byte-by-byte Description of file: head.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- File Model file name
13- 16 I4 --- N [5366/5491] Number of grid points
18- 35 E18.13 g M* Stellar mass
37- 54 E18.13 cm R* Stellar radius
56- 73 E18.13 10-7W L* Stellar luminosity (erg/s)
75- 76 I2 --- Ncol [19] Number of columns in the model file
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Byte-by-byte Description of file (#): model*.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- id [1/5372] Cell number
12- 33 D22.16 cm r Radius
39- 60 D22.16 --- w Dimensionless mass (Mr/(M*-Mr)
66- 87 D22.16 mW/m2 Lr Total luminosity
93-114 D22.16 dyn/cm2 p Pressure
120-141 D22.16 K T Temperature
147-168 D22.16 g/cm3 rho Density ρ
174-195 D22.16 --- nabla Temperature gradient (d(ln(T))/d(ln(p)))
200-222 D23.16 Hz2 N2 Brunt-Vaisala frequency squared
228-249 D22.16 --- Gamma1 First adiabatic index
(d(ln(p)/d(ln(ρ))ad)
255-276 D22.16 --- nablaAd Adiabatic temperature gradient
((d(ln(T))/d(ln(p)))ad
282-303 D22.16 --- delta -(d(ln(ρ))/d(ln(T)))p
309-330 D22.16 cm2/g kappa Rosseland mean opacity κ
335-357 D23.16 --- kappaT (d(lnκ)/d(lnT))ρ
363-384 D22.16 --- kapparho (d(lnκ)/d(lnrho))T
390-411 D22.16 10-7W/g/s epsnuc Nuclear energy generation rate εnuc
417-438 D22.16 10-7W/g/s epsT (d(epsd)/ln(T))_T
444-465 D22.16 10-7W/g/s epsrho (d(epsd)/ln(rho))rho
471-492 D22.16 rad/s Omega [0] Rotation angular velocity
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Acknowledgements:
Ehsan Moravveji, ehsan.moravveji(at)ster.kuleuven.be
(End) E. Moravveji [IvS, KU Leuven, Belgium], P. Vannier [CDS] 01-Jun-2015