J/A+A/697/A165 Evolutionay status of Kepler red giants (Vrard+, 2025)
Red giants evolutionary status determination: the complete Kepler catalog.
Vrard M., Pinsonneault M.H., Elsworth Y., Hon M., Kallinger T.,
Kuszlewicz J., Mosser B., Garcia R.A., Tayar J., Bennett R., Cao K.,
Hekker S., Loyer L., Mathur S., Stello D.
<Astron. Astrophys. 697, A165 (2025)>
=2025A&A...697A.165V 2025A&A...697A.165V (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Asteroseismology ; Effective temperatures ; Optical
Keywords: stars: evolution - stars: interiors - stars: oscillations -
stars: solar-type
Abstract:
Evolved cool stars have three distinct evolutionary status: shell
Hydrogen-burning (RGB), core Helium and shell Hydrogen burning (RC),
and double shell burning (AGB). Asteroseismology can distinguish
between the RC and the other status, but distinguishing RGB and AGB
has been difficult seismically and spectroscopically. The precise
boundaries of different status in the HR diagram have also been
difficult to establish. Aims: in this article, we present a
comprehensive catalog of asteroseismic evolutionary status, RGB and
RC, for evolved red giants in the Kepler field. We carefully examine
boundary cases to define the lower edge of the RC phase in radius and
surface gravity. We also test different published asteroseisemic
methods claiming to distinguish AGB and RGB stars against a sample
where AGB candidates were selected using a spectroscopic identification
method. methods: we used six different seismic techniques to
distinguish RC and RGB stars, and tested two proposed methods for
distinguishing AGB and RGB stars. These status were compared with
those inferred from spectroscopy. Results: we present consensus
evolutionary status for 18784 stars out of the 30337 red giants
present in the Kepler data, including 11516 stars with APOGEE spectra
available. The agreement between seismic and spectroscopic
classification is excellent for distinguishing RC stars, agreeing at
the 94% level. Most disagreements can be traced to uncertainties in
spectroscopic parameters, but some are caused by blends with
background stars. We find a sharp lower boundary in surface gravity at
log(g)=2.99±0.01 for the RC and discuss the implications. We
demonstrate that asteroseismic tools for distinguishing AGB and RGB
stars are consistent with spectroscopic evolutionary status at near
the RC (with the asteroseismic large separation {DELTA}{NU}≤2uHz) but
that the agreement between the different methods decreases rapidly as
the star evolves during the AGB phase. Conclusions: this work present
the most complete evolutionary status catalog for Kepler and APOGEE
red giant stars. The data precisely defines the locus of RC stars in
the HR diagram, an important constraint for stellar theory and stellar
populations. We also demonstrate that asteroseismic tools can
distinguish between AGB and RGB stars under some circumstances, which
is important for the age estimation for field stars. However, we also
put forward the importance of using several techniques to assess the
evolutionary status determination for luminous red giants
Description:
Evolutionary status of more than 18000 red giant stars present in the
Kepler data. The evolutionary status was obtained with
asteroseismology. The candidate RGB and AGB stars present above the
clump are also given following spectroscopic analysis. For each star,
the Kepler identification number, the frequency of maximum
oscillation, the global large separation, the possibility to
determinate an evolutionary status and the result of the evolutionary
status are given. For the candidate AGB and RGB stars, the Kepler
Identification number, the effective temperature, the surface gravity,
the reference temperature and the evolutionary status are also given
in a separate file.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 26 30337 Evolutionary status (clump or RGB/AGB) of the
Kepler red giant sample
table4.dat 38 2237 Evolutionarys status (AGB/RGB) of the red giants
above the clump
--------------------------------------------------------------------------------
See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- KIC Kepler identification number
11- 15 F5.1 uHz numax Frequency of maximum oscillation
17- 21 F5.2 uHz dnu Large separation frequency
23 I1 --- Result [0/1]? Possibility to determine an
evolutionary status (1)
25- 26 I2 --- EV [-1/2] Evolutionary status (2)
--------------------------------------------------------------------------------
Note (1): Code es follow:
0 = undetermined evolutionary status
1 = robust evolutionary status
Note (2): Code es follow:
1 = RGB/AGB
2 = clump
-1 = undetermined evolutionary status
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- KIC Kepler identification number
10- 13 I4 K Teff Effective Temperature
15- 17 I3 K e_Teff 1-sigma uncertainties on effective temperature
19- 22 F4.2 [cm/s2] logg logarithm of surface gravity
24- 27 F4.2 [cm/s2] e_logg 1-sigma uncertainties on logarithm of
surface gravity
29- 36 F8.2 K Tref Tref value from APOGEE data
38 I1 --- EV [0/2]? Evolutionary status (1)
--------------------------------------------------------------------------------
Note (1): Code as follows:
0 = AGB/RGB
1 = certain RGB
2 = candidate AGB
--------------------------------------------------------------------------------
Acknowledgements:
Mathieu Vrard, mathieu.vrard(at)oca.eu
(End) Mathieu Vrard [OCA, France], Patricia Vannier [CDS] 18-Mar-2025