J/A+A/569/A21 Age and mass of CoRoT exoplanet host HD 52265 (Lebreton, 2014)
Asteroseismology for "a la carte" stellar age-dating and weighing.
Age and mass of the CoRoT exoplanet host HD 52265.
Lebreton Y., Goupil M.
<Astron. Astrophys. 569, A21 (2014)>
=2014A&A...569A..21L 2014A&A...569A..21L
ADC_Keywords: Stars, double and multiple ; Planets ; Stars, masses ;
Stars, ages ; Models
Keywords: asteroseismology - stars: interiors - stars: fundamental parameters -
planets and satellites: fundamental parameters -
stars: individual: HD 52265 - stars: interiors
Abstract:
In the context of space missions CoRoT, Kepler, Gaia, TESS, and PLATO,
precise and accurate stellar ages, masses and radii are of paramount
importance. For instance, they are crucial to constrain scenarii of
planetary formation and evolution.
Description:
The displayed models aim at quantifying how detailed stellar modeling
can improve the accuracy and precision on age and mass of individual
stars. We adopted a multifaceted approach where we examined carefully
how the number of observational constraints as well as the
uncertainties on observations and on model input physics affect the
results of stellar age-dating and weighing. The modeling concerns a
case study, the exoplanet host-star HD 52265, a main-sequence,
solar-like oscillator that CoRoT observed during four months. We
considered different sets of observational constraints
(Hertzsprung-Russell data, metallicity, and various sets of seismic
constraints). For each case, we determined the age, mass, and
properties of HD 52265 inferred from stellar models, and we quantified
the impact of the models input physics and free parameters. We also
determined the properties of its exoplanet.
Objects:
--------------------------------------------------
RA (ICRS) DE Designation(s)
--------------------------------------------------
07 00 18.04 -05 22 01.8 HD 52265 = HR 2622
--------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 132 9 Model results for the reference physics
(set A, different cases)
table5.dat 99 9 Model restitution of the chosen observational
constraints plus quantities of interest
tablea2.dat 132 29 Model results for the reference physics for
different optimization options
tablea3.dat 99 29 Model restitution of the chosen observational
constraints plus quantities of interest
for different optimization options
tablea4.dat 132 90 Model results for the reference physics for
different input physics of the models
tablea5.dat 99 90 Model restitution of the chosen observational
constraints plus quantities of interest
for different input physics of the models
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat tablea2.dat tablea4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Model Model identification (G1)
14- 18 F5.2 Gyr Age [0.8/4.5] Age
20- 24 F5.2 Gyr e_Age Age error bar (1)
26- 30 F5.2 Msun M [1.12/1.43] Stellar mass
32- 36 F5.2 Msun e_M Mass error bar (1)
38- 43 F6.4 --- Z/X0 [0.03/0.07] Initial metal to hydrogen ratio
45- 50 F6.4 --- e_Z/X0 Z/X error bar (1)
52- 58 F7.3 --- Y0 Initial helium content
60- 66 F7.3 --- e_Y0 ?=-99.999 Y error bar (1)
68- 74 F7.3 --- al.conv [0.4/2.1] Mixing length parameter convection
αconv
76- 82 F7.3 --- e_al.conv ?=-99.999 alpha conv error bar (1)
84- 87 F4.2 --- al.ov [0/2] Overshooting parameter αov
89- 92 F4.2 --- xiPC [0/1.3] Penetrative convection parameter
ξPC
94-100 F7.3 --- b [3.5/5.6]?=-99.999 Near surface effects
correction exponent bSE (2)
102-108 F7.3 --- a [-9.1/-0.8]?=-99.999 Near surface effects
correction factor aSE (2)
110-116 F7.3 --- r [1.000/1.003]?=-99.999 Near surface_effects
correction parameter rSE (2)
118-124 E7.2 --- chi2.c Reduced chi square for classical parameters
χ2classic
126-132 E7.2 --- chi2.s Reduced chi square for seismic parameters
χ2seism
--------------------------------------------------------------------------------
Note (1): The uncertainties result from the Levenberg-Marquardt minimization
procedure. No uncertainty (value -99.999) is indicated when the parameter has
not been inferred but fixed because of to few observational constraints.
Note (2): near-surface corrections (Eq.(12)):
νcorr-νmod = a/r[νobs/νmax]b
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat tablea3.dat tablea5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Model Model identification (G1)
14- 18 F5.0 K Teff [5958/6228] Effective temperature
20- 24 F5.3 Lsun Lum [2.01/2.16] Luminosity
27- 30 F4.2 [Sun] [Fe/H] [0.19/0.39] Metallicity
32- 35 F4.2 [cm/s2] logg [4.27/4.42] Surface gravity
37- 40 F4.2 Rsun R [1.22/1.36] Radius
42- 47 F6.2 uHz dnu [98/121] Mean large frequency separation
<Δν>
49- 53 F5.0 uHz numax [2025/2807] Frequency at maximum power
νmax
56- 60 F5.3 --- r02 [0.05/0.11] Mean small frequency separation
ratio <r02>
63- 67 F5.3 --- rr01/10 [0.01/0.04] Mean small frequency separation
ratio <rr01/10>
69- 72 F4.2 --- Xc [0/0.7] Central hydrogen abundance Xc
75- 77 F3.1 --- dY/dZ [0/3.6] Helium to metal enrichment ratio
ΔY/ΔZ
79- 83 F5.3 Msun Mcc [0/0.14] Convective core mass Mcc
85- 89 F5.3 Rsun Rzc [0.69/0.87] Bottom of convective envelope
radius Rzc
91- 94 F4.2 Mjup Mpsini [1.14/1.34] Exoplanet mass Mpsin(i),
in Jupiter mass
96- 99 F4.2 Mjup e_Mpsini [0.03/0.05] Mpsini error bar,
------------------------------------------------------------------------------
Global notes:
Note (G1):
Table 2: Summary of the different sets of input physics considered
for the modelling of HD 52265
----------------------------------------------------------------------
Set Input physics
----------------------------------------------------------------------
A REF (based on OPAL05 EoS, 2002ApJ...576.1064R 2002ApJ...576.1064R)
B convection MLT (mixing length theory)
C AGSS09 mixture (2009ARA&A..47..481A 2009ARA&A..47..481A)
D NACRE for 14N(p, gamma)15O (NACRE+LUNA reaction rates)
E no microscopic diffusion
G B69 for microscopic diffusion
F Kurucz model atmosphere, MLT
H EoS OPAL01 downwards
I overshooting αov=0.15Hp
J overshooting Mov,c=1.8xMcc
K penetrative convection ξPC=1.3Hp
----------------------------------------------------------------------
Table 3: We considered the following cases of observational constraints:
-----------------------------------------------------------------------
Case Observed
-----------------------------------------------------------------------
1 Teff, L, [Fe/H]
2 Teff, L, [Fe/H], <Deltanu>
3 Teff, L, [Fe/H], <Deltanu>, numax
4 Teff, L, [Fe/H], <Deltanu>, <d02>
5 Teff, L, [Fe/H], <r02>, <r01/10>
6 Teff, L, [Fe/H], r_02(n), r01/10(n)
7 Teff, L, [Fe/H], nun,l
------------------------------------------------------------------------
(where <Deltanu> is the mean large frequency separation,
numax is the frequency at maximum power,
d02 is the mean small frequency separation,
d02(n) the individual small frequency separation,
r01/10 are the mean small frequency separation ratio,
r01/10(n) the individual small frequency separation ratio,
and nun,l the individual oscillation frequency)
-------------------------------------------------------------------------
Table A1: Specifications of extra optimized models assuming
different prescriptions for the modelling
----------------------------------------------------
Set Case Particularities
----------------------------------------------------
A 1-Y/2-Y Y=0.25/0.27
A 1-α0.550 αconv=0.550
A 1-α0.826 αconv=0.826
A 1-ov0.30 αov=0.30
A 1, 2a, 7-vrad
A 5-allfreq
A 6-nocorrel
A 6-interR
A 6, 7-ov optimized overshoot
A 6, 7-YM Y-M degeneracy
A 7-noSE no SE corrections
A 7-bSE4.9 solar SE corrections
A 7-pms
A 7-rot rotation
----------------------------------------------------
--------------------------------------------------------------------------------
Acknowledgements:
Yveline Lebreton, yveline.lebreton(at)obspm.fr
(End) Patricia Vannier [CDS] 04-Jul-2014