J/ApJ/857/119 Asymmetry of oscillations in 43 Kepler stars (Benomar+, 2018)
Asymmetry of line profiles of stellar oscillations measured by Kepler for
ensembles of solar-like oscillators: impact on mode frequencies and dependence
on effective temperature.
Benomar O., Goupil M., Belkacem K., Appourchaux T., Nielsen M.B., Bazot M.,
Gizon L., Hanasoge S., Sreenivasan K.R., Marchand B.
<Astrophys. J., 857, 119 (2018)>
=2018ApJ...857..119B 2018ApJ...857..119B
ADC_Keywords: Asteroseismology; Stars, G-type
Keywords: methods: data analysis ; stars: interiors ;
stars: oscillations (including pulsations)
Abstract:
Oscillation properties are usually measured by fitting symmetric
Lorentzian profiles to the power spectra of Sun-like stars. However,
the line profiles of solar oscillations have been observed to be
asymmetrical for the Sun. The physical origin of this line asymmetry
is not fully understood; though, it should depend on the depth
dependence of the source of wave excitation (convective turbulence)
and details of the observable (velocity or intensity). For
oscillations of the Sun, it has been shown that neglecting the
asymmetry leads to systematic errors in the frequency determination.
This could subsequently affect the results of seismic inferences of
the solar internal structure. Using light curves from the Kepler
spacecraft, we have measured mode asymmetries in 43 stars. We confirm
that neglecting the asymmetry leads to systematic errors that can
exceed the 1σ confidence intervals for seismic observations
longer than one year. Therefore, the application of an asymmetric
Lorentzian profile should be favored to improve the accuracy of the
internal stellar structure and stellar fundamental parameters. We also
show that the asymmetry changes sign between cool Sun-like stars and
hotter stars. This provides the best constraints to date on the
location of the excitation sources across the Hertzsprung-Russel
diagram.
Description:
In this work, the considered ensemble of stars is a subset of the
Kepler LEGACY sample (Lund+ 2017, J/ApJ/835/172). We selected 43 stars
for analysis out of 66 of the LEGACY sample. The current analysis uses
the unweighted power spectra provided by the Kepler Asteroseismic
Science Operations Center (KASOC) pipeline (http://kasoc.phys.au.dk/).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 9 43 Studied sample; table added by CDS
table1.dat 105 1806 Measured mode frequency, width, height, asymmetry,
and frequency shift
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJ/718/L97 : Early asteroseismic results from Kepler (Van Grootel+, 2010)
J/A+A/569/A21 : Age and mass of CoRoT exoplanet host HD 52265 (Lebreton, 2014)
J/A+A/572/A34 : Pulsating solar-like stars in Kepler (Garcia+, 2014)
J/ApJS/210/1 : Asteroseismic study of solar-type stars (Chaplin+, 2014)
J/MNRAS/446/2959 : Asterosismology for 16 Cyg A/B (Davies+, 2015)
J/AJ/152/6 : Kepler star param. using LAMOST + seismic data (Wang+, 2016)
J/A+A/601/A67 : Kepler solar-type stars modeling (Creevey+, 2017)
J/ApJ/835/172 : Kepler asteroseismic LEGACY sample. I. (Lund+, 2017)
J/ApJ/844/102 : KIC parallaxes from asteroseismology vs Gaia (Huber+, 2017)
J/ApJS/237/17 : Temporal frequency shifts in 87 Kepler stars (Santos+, 2018)
http://kasoc.phys.au.dk/ : KASOC home page
http://amp.phys.au.dk/ : Asteroseismic Modeling Portal (AMP) home page
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- KIC [3427720/12258514] Kepler Input Catalog ID
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- KIC [3427720/12258514] Kepler Input Catalog ID
11- 11 I1 --- l [0/3] Mode degree
13- 21 F9.4 uHz nu [550.9/5377.3] Measured mode frequency
23- 28 F6.4 uHz e_nu [0.029/5.5] Lower uncertainty in nu
30- 35 F6.4 uHz E_nu [0.028/3.8] Upper uncertainty in nu
37- 41 F5.2 --- Gamma [0.02/13.5] Full Width at Half Maximum; FWHM
43- 46 F4.2 --- e_Gamma [0.02/4] Lower uncertainty in Gamma
48- 51 F4.2 --- E_Gamma [0.03/4.2] Upper uncertainty in Gamma
53- 57 F5.2 --- H [0/34.1] Mode height
59- 62 F4.2 --- e_H [0/3.4] Lower uncertainty in H
64- 67 F4.2 --- E_H [0/5.3] Upper uncertainty in H
69- 73 F5.1 --- chi [-62.8/65.1] Asymmetry
75- 78 F4.1 --- e_chi [2.5/39] Lower uncertainty in chi
80- 83 F4.1 --- E_chi [2.5/91] Upper uncertainty in chi
85- 91 F7.4 uHz deltanu [-2.4/3.4] Frequency shift
93- 98 F6.4 uHz e_deltanu [0.029/5] Lower uncertainty in deltanu
100-105 F6.4 uHz E_deltanu [0.027/3.8] Upper uncertainty in deltanu
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Mar-2019