J/MNRAS/535/2189 delta Sct Grass parameterization (Barcelo Forteza+, 2024)
Characterizing the features of the low-amplitude peaks in delta Sct stars
with TESS.
Barcelo Forteza S., Pascual-Granado J., Suarez J.C., Garcia Hernandez A.,
Mirouh G.M., Lares-Martiz M.
<Mon. Not. R. Astron. Soc. 535, 2189-2209 (2024)>
=2024MNRAS.535.2189B 2024MNRAS.535.2189B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, A-type ; Stars, F-type ; Stars, variable ; Asteroseismology
Keywords: asteroseismology - stars oscillations (including pulsations) -
stars: variables: delta Scuti
Abstract:
The presence of low-amplitude peaks over the noise in the power
spectra of δ Sct stars is frequently disregarded. These seemingly
insignificant peaks, collectively referred to as grass, might contain
valuable information about the origin of these stars and the reasons
behind the occurrence or absence of a plateau. It is crucial to
systematically parameterize the grass phenomenon throughout a
comprehensive sample that covers the entire δ Sct star parameter
range. Thus, we conduct a quantitative study of long-duration,
high-duty-cycle TESS light curves, leading to improved detection
methods for plateaus and a deeper understanding of their nature.
This approach minimizes the impact of unresolved peaks caused by mode
variations over time. Additionally, we present appropriate analysis
techniques to mitigate window effects and identify and eliminate
spurious peaks.
We demonstrate here that the grass can be effectively parameterized
based on peak density. With such parameterization two distinct regimes
are found: the sparse grass regime, characterized by low peak density
and the absence of a plateau in the power spectra, and the dense grass
regime, characterized by high peak densities and the presence of an
observable plateau. Our study is the first rigorous quantification of
the emergence of such a plateau in the power spectra of δ Sct.
Since the grass might be related with fractality, mode variability,
and stellar rotation rate, its parameterization opens a new way to
analyze these stars.
Description:
Here we show the values of the grass parameterization compared to
the structural parameters of each δ Sct star. We also indicate
the frequency and amplitude of the envelope peaks for each star.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 175 36 Grass parameterization for delta Sct stars
envpeaks/* . 36 *Individual envelope peaks
--------------------------------------------------------------------------------
Note on envpeaks/*: In addition to the Envelope peaks we also added
high-amplitude peaks in lower frequency regimes at the end of the list.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- TIC TESS ID number
11- 16 I6 --- HD ? Henry Draper ID Number
18- 21 I4 K Teff Effective temperature (1)
23- 25 I3 K e_Teff Error of Teff (1)
27- 30 F4.1 [cm/s2] logg Surface gravity (1)
32- 34 F3.1 [cm/s2] e_logg Error of surface gravity (1)
36- 39 A4 --- SpType Spectral type (2)
41- 46 F6.3 [-] [Fe/H] ? Metallicity (1)
48- 54 F7.3 km/s vsini ? Projected velocity or lower value of
vsini interval(2)
55 A1 --- --- [-]
56- 57 I2 km/s vsini2 ? Upper value of vsini interval
59 I1 km/s e_vsini ? Error on vsini (2)
61- 83 A23 --- Comment Object type (2)
85- 87 I3 uHz nu-lambda Frequency at minimum peak density
89- 90 I2 uHz e_nu-lambda Error of nu-lambda
92- 94 I3 uHz nu-c ? Cut-off frequency
96 I1 uHz e_nu-c ? Error of nu-c
98-105 F8.3 uHz nu-N Highest frequency detected
107-111 F5.2 ppm Amean ? Mean amplitude of the plateau
113-116 F4.2 ppm e_Amean ? Error of A_mean
118-122 F5.3 --- Xi ? Plateau factor
124-128 F5.3 --- e_Xi ? Error of the plateau factor
130-133 F4.2 1/uHz nmean ? Mean density of the plateau peaks
(in peaks/uHz unit)
135-139 F5.3 1/uHz e_nmean ? Error of n_mean (in peaks/uHz unit)
141-144 F4.2 1/uHz Deltan ? Grass density decay (in peaks/uHz unit)
146-149 F4.2 1/uHz e_Deltan ? Error of Δn (in peaks/uHz unit)
151-167 A17 --- Regime Grass regime
169-175 A7 --- FileName Name of the table with envelope peaks data
in subdirectory envpeaks
--------------------------------------------------------------------------------
Note (1): From Stassun et al., 2019AJ....158..138S 2019AJ....158..138S, Cat. IV/38
Note (2): From SIMBAD database:
Cannon+ 1918-1924; ADC 1989 (1993yCat.3135....0C 1993yCat.3135....0C)
Jonsson+ 2020 (2020AJ....160..120J 2020AJ....160..120J)
Houk+ 1975 (1975mcts.book.....H 1975mcts.book.....H)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: envpeaks/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 F20.5 uHz Freq Frequency of the oscillation
21- 40 F20.5 ppm Amp Amplitude of the oscillation
--------------------------------------------------------------------------------
History:
From Sebastia Barcelo Forteza, sbarceloforteza(at)ugr.es
Acknowledgements:
This research has made use of the SIMBAD database, CDS,
Strasbourg Astronomical Observatory, France
(End) Patricia Vannier [CDS] 27-Oct-2024