J/A+A/702/A144 Beyond the Nyquist frequency (Liagre+, 2025)
Beyond the Nyquist frequency: Asteroseismic catalog of undersampled Kepler late
subgiants and early red giants.
Liagre B., Garcia R.A., Mathur S., Pinsonneault M.H., Serenelli A.,
Zinn J.C., Cao K., Godoy-Rivera D., Tayar J., Beck P.G., Grossmann D.H.,
Palakkatharappil D.B.
<Astron. Astrophys. 702, A144 (2025)>
=2025A&A...702A.144L 2025A&A...702A.144L (SIMBAD/NED BibCode)
ADC_Keywords: Asteroseismology ; Stars, giant ; Abundances ; Optical ;
Morphology
Keywords: asteroseismology - methods: data analysis - stars: evolution -
stars: interiors - stars: oscillations
Abstract:
Subgiants and early red giants are crucial for studying the first
dredge-up, a key evolutionary phase in which the convective envelope
deepens, mixing previously interior-processed material and bringing it
to the surface. Yet, very few have been seismically characterized with
Kepler because their oscillation frequencies are close to the 30
minute sampling frequency of the mission. We developed a new method as
part of the new PyA2Z code of identifying super-Nyquist oscillators
and inferring their global seismic parameters, νmax and large
separation, Δν.
Applying PyA2Z to 2065 Kepler targets, we seismically characterize 285
super-Nyquist and 168 close-to-Nyquist stars with masses from 0.8 to
1.6M☉. In combination with APOGEE spectroscopy, Gaia
spectrophotometry, and stellar models, we derive stellar ages for the
sample. There is good agreement between the predicted and actual
positions of stars on the HR diagram (luminosity vs. effective
temperature) as a function of mass and composition. While the timing
of dredge-up is consistent with predictions, the magnitude and mass
dependence show discrepancies with models, possibly due to
uncertainties in model physics or calibration issues in observed
abundance scales.
Description:
The catalog.dat contains the full set of asteroseismic (and
spectroscopic parameters) derived for 2065 Kepler stars. The catalog
is based on Kepler long-cadence photometry combined with APOGEE
spectra, Gaia DR3 astrometry, and literature values. Stellar masses,
radii, and ages are computed using standard corrected seismic scaling
relations. Uncertainties are provided for all measured quantities.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 500 2065 Asteroseismic and spectroscopic catalog
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- KIC ?=- Kepler Input Catalog identifier
10- 29 F20.15 uHz numax ?=- Frequency of maximum oscillation power
31- 50 F20.15 uHz Dnu ?=- Large frequency separation
52- 72 F21.16 uHz e_numax ?=- Uncertainty on Numax
74- 97 F24.19 uHz e_Dnu ?=- Uncertainty on Dnu
99-118 A20 --- Cat Category (super-Nyquist, sub-Nyquist, etc.)
120-127 F8.4 --- [alpha/Fe] ?=- Abundance [alpha/Fe]
129-136 F8.4 --- e_[alpha/Fe] ?=- Uncertainty on [alpha/Fe]
138-143 F6.4 [cm/s2] loggSpec ? Spectroscopic surface gravity
145-150 F6.4 [cm/s2] e_loggSpec ? Uncertainty on spectroscopic logg
152-161 F10.4 --- [C/Fe] ?=- Abundance [C/Fe]
163-172 F10.4 --- e_[C/Fe] ?=- Uncertainty on [C/Fe]
174-183 F10.4 --- [N/Fe] ?=- Abundance [N/Fe]
185-194 F10.4 --- e_[N/Fe] ?=- Uncertainty on [N/Fe]
196-215 F20.18 1/Rsun InvRGaia ? Inverse Gaia Radius
217-237 F21.19 1/Rsun e_InvRGaia ? Uncertainty on inverse Gaia Radius
239-245 F7.5 [cm/s2] loggseis ? Seismic surface gravity
247-255 F9.7 [cm/s2] e_loggseis ? Uncertainty on seismic logg
257-264 F8.6 Msun Mass ? Stellar mass
266-285 F20.18 Msun e_Mass ? Uncertainty on stellar mass
287-295 F9.6 Rsun Radius ? Stellar radius
297-316 F20.18 Rsun e_Radius ? Uncertainty on stellar radius
318-325 F8.6 --- Fdnu ? Frequency separation correction factor
327-337 F11.9 --- e_Fdnu ? Uncertainty on Fdnu
339-345 F7.4 Gyr Age ? Stellar age
347-353 F7.4 Gyr E_Age ? Upper uncertainty on RGB age
356-361 F6.4 Gyr e_Age ? Lower uncertainty on RGB age
363-371 F9.4 K Teff ? Effective temperature
373-379 F7.4 K e_Teff ? Uncertainty on effective temperature
381-388 A8 --- Source Source catalog (APOKASC3, XGBoost, etc.)
390-396 F7.4 [-] [Fe/H] ? Metallicity [Fe/H]
398-402 F5.3 [-] e_[Fe/H] ? Uncertainty on [Fe/H]
404-425 E22.16 Lsun L ? Luminosity
427-449 E23.16 Lsun e_L ? Uncertainty on luminosity
451-469 I19 --- GaiaDR3 ? Gaia DR3 source identifier
471-479 I9 --- TIC ? TESS Input Catalog identifier
481-497 A17 --- 2MASS 2MASS identifier
499-500 I2 --- Nquarters ? Number of Kepler observing quarters
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Acknowledgements:
From Bastien Liagre, bastienliagre(at)hotmail.fr
This paper includes data collected by the Kepler mission and obtained
from the MAST data archive at the Space Telescope Science Institute
(STScI). Funding for the Kepler mission is provided by the NASA
Science Mission Directorate. STScI is operated by the Association of
Universities for Research in Astronomy, Inc., under NASA contract NAS
5-26555.
(End) Patricia Vannier [CDS] 30-Sep-2025