J/A+A/600/A1 Coupling factors of 5166 KIC (Mosser+, 2017)
Period spacings in red giants. III. Coupling factors of mixed modes.
Mosser B., Pincon C., Belkacem K., Takata M., Vrard M.
<Astron. Astrophys., 600, A1 (2017)>
=2017A&A...600A...1M 2017A&A...600A...1M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Spectroscopy
Keywords: stars: oscillations - stars: interiors - stars: evolution
Abstract:
The power of asteroseismology relies on the capability of global
oscillations to infer the stellar structure. For evolved stars, we
benefit from unique information directly carried out by mixed modes
that probe their radiative cores. This third article of the series
devoted to mixed modes in red giants focuses on their coupling
factors, which have remained largely unexploited up to now.
With the measurement of coupling factors, we intend to give physical
constraints on the regions surrounding the radiative core and the
hydrogen-burning shell of subgiants and red giants.
A new method for measuring the coupling factor of mixed modes was
implemented, which was derived from the method recently implemented
for measuring period spacings. This new method was automated so that
it could be applied to a large sample of stars.
Coupling factors of mixed modes were measured for thousands of red
giants. They show specific variation with mass and evolutionary stage.
Weak coupling is observed for the most evolved stars on the red giant
branch only; large coupling factors are measured at the transition
between subgiants and red giants as well as in the red clump.
The measurement of coupling factors in dipole mixed modes provides a
new insight into the inner interior structure of evolved stars. While
the large frequency separation and the asymptotic period spacings
probe the envelope and core, respectively, the coupling factor is
directly sensitive to the intermediate region in between and helps
determine its extent. Observationally, the determination of the
coupling factor is a prior to precise fits of the mixed-mode pattern
and can now be used to address further properties of the mixed-mode
pattern, such as the signature of buoyancy glitches and core rotation.
Description:
Seismic global parameters of the stars listed in the paper. Each star
is identified with its KIC number (Kepler Input Catalog).
Coupling factors of mixed modes were measured for thousands of red
giants. They show specific variation with mass and evolutionary stage.
Weak coupling is observed for the most evolved stars on the red giant
branch only; large coupling factors are measured at the transition
between subgiants and red giants as well as in the red clump. Period
spacings and evolutionary stages are from Vrard et (2016, Cat.
J/A+A/588/A87).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
couplage.dat 46 5166 Seismic global parameters
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/A+A/540/A143 : Oscillations of red giants observed by Kepler (Mosser+, 2012)
J/A+A/588/A87 : Seismic global parameters of 6111 KIC (Vrard+, 2016)
Byte-by-byte Description of file: couplage.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- KIC KIC number
10- 17 F8.2 muHz Dnu Large separation
18- 25 F8.1 s DPi1 Period spacing
26- 32 F7.2 --- q Coupling factor
33- 39 F7.2 --- e_q Uncertainty in q
40- 46 F7.2 Msun Mass Mass (seismic estimate)
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Acknowledgements:
Benoit Mosser, benoit.mosser(at)obspm.fr
References:
Mosser et al., Paper I 2015A&A...584A..50M 2015A&A...584A..50M
Vrad et al., Pqper II 2016A&A...588A..87V 2016A&A...588A..87V, Cat. J/A+A/588/A87
(End) Patricia Vannier [CDS] 07-Aug-2017