J/A+A/531/A124 Visibilities of stellar oscillation modes (Ballot+, 2011)
Visibilities and bolometric corrections for stellar oscillation modes observed
by Kepler.
Ballot J., Barban C., van't Veer-Menneret C.
<Astron. Astrophys. 531, A124 (2011)>
=2011A&A...531A.124B 2011A&A...531A.124B
ADC_Keywords: Models, atmosphere
Keywords: asteroseismology - stars: atmospheres - stars: solar-type
Abstract:
Kepler produces a large amount of data used for asteroseismological
analyses, particularly of solar-like stars and red giants. The mode
amplitudes observed in the Kepler spectral band have to be converted
into bolometric amplitudes to be compared to models. We give a simple
bolometric correction for the amplitudes of radial modes observed with
Kepler, as well as the relative visibilities of non-radial modes. We
numerically compute the bolometric correction cK-bol and mode
visibilities, for different effective temperatures Teff within the
range 4000-7500K, using a similar approach to a recent one from the
literature. We derive a law for the correction to bolometric values:
cK-bol=1+a1(Teff-To)+a2(Teff-To)2, with To=5934K,
a1=1.349e-4K-1, and a2=-3.120e-9K-2 or, alternatively, as the
power law cK-bol=(Teff/To)alpha with alpha=0.80. We give tabulated
values for the mode visibilities based on limb-darkening, computed
from ATLAS9 model atmospheres for Teff in [4000,7500]K, logg in
[2.5,4.5], and [M/H] in [-1.0,+1.0]. We show that using LD profiles
already integrated over the spectral band provides quick and good
approximations for visibilities. We point out the limits of these
classical visibility estimations.
Description:
These are computations of visibilities of non-radial modes for the
Kepler mission.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 34 487 Visibilities of oscillation modes for Kepler
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See also:
J/A+A/529/A89 : Kepler satellite variability study (Debosscher+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 K Teff [4000,7500] Stellar effective temperature
6- 8 F3.1 [cm/s+2] logg [2.5,4.5] Stellar surface gravity
10- 13 F4.1 [Sun] M/H [-1.0,+1.0] Stellar metallicity (1)
15- 18 F4.2 --- V2.t Total visibilities (2)
20- 23 F4.2 --- V2.1 Visibilities for l=1 mode (2)
25- 28 F4.2 --- V2.2 Visibilities for l=2 mode (2)
30- 34 F5.3 --- V2.3 Visibilities for l=3 mode (2)
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Note (1): The metallicity is log[metal/H]-log[(metal/H)_☉].
Note (2): Vl is the visibility of a mode of degree l, i.e. the apparent
amplitude of this mode compared to a radial mode (l=0) that would have
the same intrinsic amplitude at the surface of the star. By definition,
V0=1. Here the values of Vl2 are tabulated, they correspond to
mode visibilities in oscillation power spectra. The total visibility
Vt2 is defined as the sum of Vl2 l=0 to infinity.
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Acknowledgements:
Jerome Ballot, jballot(at)ast.obs-mip.fr
(End) Jerome Ballot [IRAP, France], Patricia Vannier [CDS] 07-Jun-2011