J/MNRAS/466/3344 Red-giant stars classification (Elsworth+, 2017)
A new method for the asteroseismic determination of the evolutionary state of
red-giant stars.
Elsworth Y., Hekker S., Basu S., Davies G.R.
<Mon. Not. R. Astron. Soc., 466, 3344-3352 (2017)>
=2017MNRAS.466.3344E 2017MNRAS.466.3344E (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Asteroseismology ; MK spectral classification
Keywords: asteroseismology - stars: evolution - stars: low-mass -
stars: oscillations
Abstract:
Determining the ages of red-giant stars is a key problem in stellar
astrophysics. One of the difficulties in this determination is to know
the evolutionary state of the individual stars - i.e. have they
started to burn Helium in their cores? That is the topic of this
paper. Asteroseismic data provide a route to achieving this
information. What we present here is a highly autonomous way of
determining the evolutionary state from an analysis of the power
spectrum of the light curve. The method is fast and efficient and can
provide results for a large number of stars. It uses the structure of
the dipole-mode oscillations, which have a mixed character in
red-giant stars, to determine some measures that are used in the
categorization. It does not require that all the individual components
of any given mode be separately characterized. Some 6604 red-giant
stars have been classified. Of these, 3566 are determined to be on the
red-giant branch, 2077 are red-clump and 439 are secondary-clump
stars. We do not specifically identify the low-metallicity,
horizontal-branch stars. The difference between red-clump and
secondary-clump stars is dependent on the manner in which Helium
burning is first initiated. We discuss that the way the boundary
between these classifications is set may lead to mis-categorization in
a small number of stars. The remaining 522 stars were not classified
either because they lacked sufficient power in the dipole modes
(so-called depressed dipole modes) or because of conflicting values in
the parameters.
Description:
A robust method to determine the evolutionary state of red-giant stars
has been presented here.
The resulting classification for all the stars analysed is presented.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 21 6637 Classification for all the stars analysed
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- KIC KIC number
10- 21 A12 --- Class Classification (1)
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Note (1): Classification as follows:
RGB = red-giant branch
RC = red clump
2CL = secondary clump
U = unclassified
nmx-too-high = νmax is above the range considered
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 14-Nov-2019