J/A+A/710/A111 CRIRES+ lines study for six GBS stars (Elgueta+, 2026)
Gaia FGK benchmark stars: Selecting infrared lines for abundance determination.
Elgueta S., Jofre P., Aguilera-Gomez C., Slumstrup D., Rojas Arriagada A.,
Heiter U., Casamiquela L., Zoccali M., Worley C., Soubiran C.
<Astron. Astrophys. 710, A111 (2026)>
=2026A&A...710A.111E 2026A&A...710A.111E (SIMBAD/NED BibCode)
ADC_Keywords: Stars, F-type ; Stars, G-type ; Stars, K-type ; Stars, giant ;
Stars, dwarfs ; Spectroscopy ; Spectra, infrared ;
Effective temperatures ; Abundances, [Fe/H] ; Atomic physics ;
Excitation rates ; Infrared ; MK spectral classification
Keywords: line: identification - methods: laboratory: atomic -
techniques: spectroscopic - stars: abundances - stars: atmospheres -
infrared: stars -
Abstract:
The advent of new and more powerful infrared spectrographs has
significantly motivated the advancement of the study of atomic and
molecular line lists and stellar atmosphere models. While optical
abundance determinations rely on extensively validated line lists and
modeling frameworks, infrared measurements still face larger
uncertainties, largely driven by the choice of atmospheric models and
the quality of the available atomic data. In this work, we aim to
deliver a homogeneous and reproducible set of atomic absorption lines
in the Y, J, and H bands (9800-18000 Å), based exclusively on
laboratory atomic data. We analyse CRIRES spectra of six Gaia FGK
Benchmark Stars spanning a wide range in effective temperature,
surface gravity, and chemical composition. Synthetic spectra are
computed using the benchmark stellar parameters, and each transition
is evaluated independently in every star through a quantitative
sequence that examines line depth, saturation, blending (purity), and
the agreement between observed and synthetic line profiles. We
identify a set of robust atomic transitions in these bands that remain
consistent across the full range of stellar parameters represented in
our sample. Lines of α-elements such as MgI, SiI, and CaI,
together with several FeI transitions, satisfy all robustness
criteria. Among the neutron-capture species explored, only SrII
provides lines that consistently meet our requirements. Beyond the
specific list of accepted transitions, this study demonstrates that a
fully quantitative, multi-criteria framework provides a transparent
and reproducible foundation for near-infrared line validation as
laboratory data, stellar atmosphere models, and instrumentation
continue to improve.
Description:
Infrared spectroscopic observations offer a significant advantage over
optical observations when studying heavily obscured by interstellar
extinction. In this work, we will explore the IR extension of the Gaia
FGK Benchmark Stars (GBS), which represent a thoughtfully curated
collection of reference stars crucial for calibrating and validating
spectroscopic techniques. These stars cover a wide range of spectral
types, including F, G, K, and M at varying luminosities and
metallicities. From studies (see section Introduction), we get a
comprehensive observational data that allow independent determination
of their stellar parameters. Using the high resolution of CRIRES we
analyze six spectra from GBSOur primary goal is to identify a global
set of reliable absorption lines that provide consistent abundance
measurements across a wide range of stellar parameters in the CRIRES
Y, J, and H bands. To achieve this, we provide line recommendations
for each spectral type individually. All selections are based on a
series of quantitative criteria using VALD3 database. More, we aim to
work with a line list anchored to laboratory atomic data. We have
illustrated a method tracing the journey of two absorption lines:
SiI (10786.849Å) and SrII (10036.653Å) in the Y band
across different spectral types in order to show method's performance
on two distinct cases: a standard α-element widely used in
abundance studies, and a key n-capture element. At each step, using
depth evaluation, saturation checking, purity assessment, and fit
quality, we show how these spectral features are progressively
filtered, accepted, flagged as uncertain, or ultimately rejected.
We used the CRIRES+ instrument with ESO's VLT at Paranal Observatory,
Chile. This upgraded version of the CRIRES instrument (CRyogenic
InfraRed Echelle Spectrograph) is a cross-dispersed echelle
spectrograph operating in the mid- and near-infrared (YJHKLM bands) at
a nominal spectral resolution of ∼100000 with the 0.2 arcsecond slit.
We analyzed spectra for a representative sample of six GBS, including
a solar spectrum obtained from observations of Vesta. Our sample spans
a wide range in stellar parameter space (Teff, logg, and [Fe/H]),
ensuring broad coverage for this study. The tables table1-10.dat
regroup respectively observational data and synthetic spectra results,
lines selected details (as number of lines peer species and bands)
with criteria including threshold and quality flags in each spectral
types defined across sections 2, 3 and 4.
Next, separately for the three IR bands and the six different spectral
types, we present for each transitions and chemical elements in
atomich/j/y.dat, spectral analysis and extractions results as commom
quantities for all SpTypes (Wave,El,LEP,loggf,C6) and specific
quantities as synthetic/observed spectra : line depths, wavelength
offsets, selection lines/depths flags (Yes/No), saturations flags, EW
purity estimators and flags, observed vs synthetic spectra statistics
as RMS, MAD, Chi2, GoF and finally the robust line selection flags.
Finally, spectroscopic observed normalized fluxes are available in
folder sp/ for the six stars in the three IR bands.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 88 6 *Stellar parameters, observational times and
spectral types for the Gaia GBS stars
table2.dat 76 12 *Summary of depth, saturation, purity, and GoF
diagnostics for SiI and SrII features in Y band
table3.dat 11 10 Number of selected infrared transitions for the
Sun compared to optical diagnostics adopted in
previous Gaia benchmark studies
table4.dat 16 73 Robust (YYYY) transitions for alf CMi F dwarf
in the Y, J, and H bands
table5.dat 16 117 Robust (YYYY) transitions for the Sun G dwarf
in the Y, J, and H bands
table6.dat 16 140 Robust (YYYY) transitions for eps Eri K dwarf
in the Y, J, and H bands
table7.dat 16 73 Robust (YYYY) transitions for alf Boo FGK giant
in the Y, J, and H bands
table8.dat 16 135 Robust (YYYY) transitions for bet Hyi FGK
sbgiant in the Y, J, and H bands
table9.dat 16 70 Robust (YYYY) transitions for gam Sge M giant
in the Y, J, and H bands
table10.dat 29 35 In and out selected line counts per species in
the Y, J, and H bands
atomich.dat 805 1085 *Atomic data and line-selection diagnostics
for the H-band transitions
atomicj.dat 805 292 *Atomic data and line-selection diagnostics
for the J-band transitions
atomicy.dat 805 323 *Atomic data and line-selection diagnostics
for the Y-band transitions
sp/* . 18 Spectroscopic observed normalized fluxes in
H,J,Y infrared CRIRES bands for our 6 stars
--------------------------------------------------------------------------------
Note on table1.dat: The evolutionary/spectral classes correspond to the
categories adopted throughout this work. Signal-to-noise ratios are given for
the Y, J, and H bands. The entry labelled Sun corresponds to the solar
reference spectrum.
Note on table2.dat: For the SiI 10786.849A and SrII 10036.653A features
in the Y band across the representative stars used in this work. The entry
labelled Sun corresponds to the solar reference spectrum.
Note on atomich.dat and atomicj.dat and atomicy.dat: Blank entries indicate
that the corresponding quantity was not available or was not measured for
that transition in that spectral type.
--------------------------------------------------------------------------------
See also:
J/A+A/705/A167 : Gaia FGK benchmark stars. Abundances (Casamiquela+, 2026)
J/A+A/682/A145 : Gaia FGK benchmark stars v3 (Soubiran+, 2024)
J/A+A/645/A106 : Atomic data for the Gaia-ESO Survey (Heiter+, 2021)
J/A+A/638/A76 : StarHorse data for 5 surveys (Queiroz+, 2020)
J/A+A/592/A70 : Gaia FGK stars: low-metallicities candidates (Hawkins+, 2016)
J/A+A/582/A81 : Gaia FGK benchmark stars: abundances (Jofre+, 2015)
J/A+A/564/A133 : Gaia FGK benchmark stars: metallicity (Jofre+, 2014)
J/ApJ/976/175 : HD 76151 and Sun near-infrared spectroscopy (Senturk+, 2024)
J/ApJ/875/129 : FeI lines in NIR spectra of Arcturus & mu Leo (Kondo+, 2019)
J/ApJ/819/103 : Abundances of two very metal-poor stars (Afsar+, 2016)
J/ApJ/751/156 : Ti and Fe lines in red supergiants (Bergemann+, 2012)
J/ApJS/221/24 : SDSS-III APOGEE H-band spectral line lists (Shetrone+, 2015)
J/AJ/151/144 : ASPCAP weights for the 15 APOGEE chemical elements
(Garcia+, 2016)
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Star Star identifier (Object)
12- 24 A13 --- SpType Evolutionary/spectral class used in this
work (Stage)
26- 29 I4 K Teff Effective temperature (Teff)
31- 32 I2 K e_Teff Uncertainty on Teff (e_Teff)
34- 37 F4.2 [cm/s2] logg Surface gravity (logg)
39- 42 F4.2 [cm/s2] e_logg Uncertainty on logg (e_logg)
44- 48 F5.2 [Sun] [Fe/H] Metallicity [Fe/H] (Fe_H)
50- 53 F4.2 [Sun] e_[Fe/H] Uncertainty on [Fe/H] (eFeH)
55- 64 A10 "Y:M:D" ObsDate Observation date (YYYY-MM-DD) (ObsDate)
66- 70 A5 "h:m" Time Observation UT time (hh:mm) (UT)
72- 74 I3 --- SNRY Signal-to-noise ratio in the Y band (SNR_Y)
76- 78 I3 --- SNRJ Signal-to-noise ratio in the J band (SNR_J)
80- 82 I3 --- SNRH Signal-to-noise ratio in the H band (SNR_H)
84- 88 F5.1 s ExpTime Exposure time (ExpTime)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- Species Species identifier (Species)
7- 15 F9.3 0.1nm Lambda Central wavelength (lambda)
17- 26 A10 --- Star Star identifier (Object)
28- 32 F5.3 --- DepS Synthetic line depth (Dsyn)
34- 38 F5.3 --- DepO Observed line depth (Dobs)
40 A1 --- Depth Depth flag (f_Depth)
42 A1 --- Sat Saturation flag (Y=unsaturated) (f_Unsat)
44- 48 F5.3 --- Purity Purity parameter P (Purity)
50 A1 --- f_Purity Purity flag (f_Purity)
52- 56 F5.3 --- RMSE Root mean square error (RMSE)
58- 62 F5.3 --- MAD Mean absolute deviation (MAD)
64- 68 F5.3 --- Chi2nu Reduced chi-square (chi2nu)
70- 74 F5.3 --- Chi2ref Reference reduced chi-square threshold
(chi2ref)
76 A1 --- GoF Goodness-of-fit flag (f_GoF)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- El Chemical element (Elem)
4- 5 I2 --- nIR Number of selected IR transitions (N_IR)
7- 8 I2 --- Nopt15 Number of optical diagnostics adopted in
Jofre et al. (2015A&A...582A..81J 2015A&A...582A..81J,
Cat. J/A+A/582/A81) (Nopt15)
10- 11 I2 --- Nopt21 Number of optical diagnostics adopted in
Heiter et al. (2021A&A...645A.106H 2021A&A...645A.106H,
Cat. J/A+A/645/A106) (Nopt21)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table[456789].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Band Spectral band (Band)
3- 6 A4 --- Species Species identifier labels with a compact
ASCII notation (Species)
8- 16 F9.3 0.1nm Lambda Central wavelength (Lambda)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Band Spectral band (Band)
3- 6 A4 --- Species Species identifier (Species)
8- 11 I4 --- Total Total number of lines (Total)
13- 14 I2 --- NFD Number of lines in the F dwarf (N_Fd)
16- 17 I2 --- NGD Number of lines in the G dwarf (N_Gd)
19- 20 I2 --- NKD Number of lines in the K dwarf (N_Kd)
22- 23 I2 --- NFGKg Number of lines in the FGK giant (N_FGKg)
25- 26 I2 --- NFGKsg Number of lines in the FGK subgiant (N_FGKs)
28- 29 I2 --- NMG Number of lines in the M giant (N_Mg)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: atomich.dat atomicj.dat atomicy.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.6 0.1nm Wave Wavelength of the transition (wavelength)
14- 17 A4 --- El Chemical element (element)
19- 27 F9.6 eV LEP ? Lower excitation potential (EP)
29- 37 F9.6 [-] loggf ? Oscillator strength (loggf)
39- 47 F9.6 --- C6 ? Van der Waals broadening constant (C6)
49- 56 F8.6 --- FDDepS ? Line depth measured in the synthetic
spectrum for F dwarf (FDwarfdepth_syn)
58- 66 F9.6 0.1nm FDWoffS ? Wavelength offset of the synthetic line
center relative to the nominal line
wavelength for F dwarf (FDwarfdelwavsyn)
68- 75 F8.6 --- e_FDDepS ? Uncertainty in the synthetic line depth
of FDDepS (FDwarfdeptherrsyn)
77- 84 F8.6 --- f_FDDepS ? Warning flag associated with the
synthetic-spectrum line measurement for F
dwarf (FDwarfwarn_synth)
86- 93 F8.6 --- FDDepO ? Line depth measured in the observed
spectrum for F dwarf (FDwarfdepth_obs)
95-105 F11.6 0.1nm FDWoffO ? Wavelength offset of the observed line
center relative to the nominal line
wavelength for F dwarf (FDwarfdelwavobs)
107-114 F8.6 --- e_FDDepO ? Uncertainty in the observed line depth of
FDDepO (FDwarfdeptherrobs)
116-124 F9.6 --- f_FDDepO ? Warning flag associated with the
observed-spectrum line measurement for F
dwarf (FDwarfwarn_obs)
126 A1 --- FDDepth Depth-selection flag (Y/N) for F dwarf
(FDwarfFlag_depth)
128 A1 --- FDSat Unsaturated-line flag (Y/N) for F dwarf
(FDwarfFlag_Unsaturated)
130-137 F8.6 --- FDPurEW ? Purity estimator based on equivalent
width for F dwarf (FDwarfPurity_EW)
139 A1 --- FDPur Purity-selection flag (Y/N) for F dwarf
(FDwarfFlag_Purity)
141-148 F8.6 --- FDRMSE ? Root-mean-square error of the observed vs
synthetic comparison for F dwarf
(FDwarfRMSE)
150-157 F8.6 --- FDMAD ? Median absolute deviation of the
residuals for F dwarf (FDwarfMAD)
159-168 F10.6 --- FDChi2 ? Reduced chi-square of the observed vs
synthetic comparison for F dwarf
(FDwarfChi2_Red)
170 A1 --- FDGoF Goodness-of-fit flag (Y/N) for F dwarf
(FDwarfFlag_GoF)
172 A1 --- FDRob Final robust-line flag (Y/N), obtained by
combining the selection criteria for F
dwarf (FDwarfRobust)
174-181 F8.6 --- GDDepS ? Line depth measured in the synthetic
spectrum for G dwarf (GDwarfdepth_syn)
183-191 F9.6 0.1nm GDWoffS ? Wavelength offset of the synthetic line
center relative to the nominal line
wavelength for G dwarf (GDwarfdelwavsyn)
193-200 F8.6 --- e_GDDepS ? Uncertainty in the synthetic line depth
of GDDepS (GDwarfdeptherrsyn)
202-209 F8.6 --- f_GDDepS ? Warning flag associated with the
synthetic-spectrum line measurement for G
dwarf (GDwarfwarn_synth)
211-219 F9.6 --- GDDepO ? Line depth measured in the observed
spectrum for G dwarf (GDwarfdepth_obs)
221-229 F9.6 0.1nm GDWoffO ? Wavelength offset of the observed line
center relative to the nominal line
wavelength for G dwarf (GDwarfdelwavobs)
231-238 F8.6 --- e_GDDepO ? Uncertainty in the observed line depth of
GDDepO (GDwarfdeptherrobs)
240-248 F9.6 --- f_GDDepO ? Warning flag associated with the
observed-spectrum line measurement for G
dwarf (GDwarfwarn_obs)
250 A1 --- GDDepth Depth-selection flag (Y/N) for G dwarf
(GDwarfFlag_depth)
252 A1 --- GDSat Unsaturated-line flag (Y/N) for G dwarf
(GDwarfFlag_Unsaturated)
254-261 F8.6 --- GDPurEW ? Purity estimator based on equivalent
width for G dwarf (GDwarfPurity_EW)
263 A1 --- GDPur Purity-selection flag (Y/N) for G dwarf
(GDwarfFlag_Purity)
265-272 F8.6 --- GDRMSE ? Root-mean-square error of the observed vs
synthetic comparison for G dwarf
(GDwarfRMSE)
274-281 F8.6 --- GDMAD ? Median absolute deviation of the
residuals for G dwarf (GDwarfMAD)
283-292 F10.6 --- GDChi2 ? Reduced chi-square of the observed vs
synthetic comparison for G dwarf
(GDwarfChi2_Red)
294 A1 --- GDGoF Goodness-of-fit flag (Y/N) for G dwarf
(GDwarfFlag_GoF)
296 A1 --- GDRob Final robust-line flag (Y/N), obtained by
combining the selection criteria for G
dwarf (GDwarfRobust)
298-305 F8.6 --- KDDepS ? Line depth measured in the synthetic
spectrum for K dwarf (KDwarfdepth_syn)
307-315 F9.6 0.1nm KDWoffS ? Wavelength offset of the synthetic line
center relative to the nominal line
wavelength for K dwarf (KDwarfdelwavsyn)
317-324 F8.6 --- e_KDDepS ? Uncertainty in the synthetic line depth
of KDDepS (KDwarfdeptherrsyn)
326-333 F8.6 --- f_KDDepS ? Warning flag associated with the
synthetic-spectrum line measurement for K
dwarf (KDwarfwarn_synth)
335-343 F9.6 --- KDDepO ? Line depth measured in the observed
spectrum for K dwarf (KDwarfdepth_obs)
345-355 F11.6 0.1nm KDWoffO ? Wavelength offset of the observed line
center relative to the nominal line
wavelength for K dwarf (KDwarfdelwavobs)
357-364 F8.6 --- e_KDDepO ? Uncertainty in the observed line depth of
KDDepO (KDwarfdeptherrobs)
366-374 F9.6 --- f_KDDepO ? Warning flag associated with the
observed-spectrum line measurement for K
dwarf (KDwarfwarn_obs)
376 A1 --- KDDepth Depth-selection flag (Y/N) for K dwarf
(KDwarfFlag_depth)
378 A1 --- KDSat Unsaturated-line flag (Y/N) for K dwarf
(KDwarfFlag_Unsaturated)
380-387 F8.6 --- KDPurEW ? Purity estimator based on equivalent
width for K dwarf (KDwarfPurity_EW)
389 A1 --- KDPur Purity-selection flag (Y/N) for K dwarf
(KDwarfFlag_Purity)
391-398 F8.6 --- KDRMSE ? Root-mean-square error of the observed vs
synthetic comparison for K dwarf
(KDwarfRMSE)
400-407 F8.6 --- KDMAD ? Median absolute deviation of the
residuals for K dwarf (KDwarfMAD)
409-419 F11.6 --- KDChi2 ? Reduced chi-square of the observed vs
synthetic comparison for K dwarf
(KDwarfChi2_Red)
421 A1 --- KDGoF Goodness-of-fit flag (Y/N) for K dwarf
(KDwarfFlag_GoF)
423 A1 --- KDRob Final robust-line flag (Y/N), obtained by
combining the selection criteria for K
dwarf (KDwarfRobust)
425-432 F8.6 --- FGKsgDepS ? Line depth measured in the synthetic
spectrum for FGK subgiant
(FGKSubgiantdepth_syn)
434-442 F9.6 0.1nm FGKsgWoffS ? Wavelength offset of the synthetic line
center relative to the nominal line
wavelength for FGK subgiant
(FGKSubgiantdelwavsyn)
444-451 F8.6 --- e_FGKsgDepS ? Uncertainty in the synthetic line depth
of FGKsgDepS (FGKSubgiantdeptherrsyn)
453-460 F8.6 --- f_FGKsgDepS ? Warning flag associated with the
synthetic-spectrum line measurement for FGK
subgiant (FGKSubgiantwarn_synth)
462-469 F8.6 --- FGKsgDepO ? Line depth measured in the observed
spectrum for FGK subgiant
(FGKSubgiantdepth_obs)
471-479 F9.6 0.1nm FGKsgWoffO ? Wavelength offset of the observed line
center relative to the nominal line
wavelength for FGK subgiant
(FGKSubgiantdelwavobs)
481-488 F8.6 --- e_FGKsgDepO ? Uncertainty in the observed line depth of
FGKsgDepO (FGKSubgiantdeptherrobs)
490-498 F9.6 --- f_FGKsgDepO ? Warning flag associated with the
observed-spectrum line measurement for FGK
subgiant (FGKSubgiantwarn_obs)
500 A1 --- FGKsgDepth Depth-selection flag (Y/N) for FGK subgiant
(FGKSubgiantFlag_depth)
502 A1 --- FGKsgSat Unsaturated-line flag (Y/N) for FGK
subgiant (FGKSubgiantFlag_Unsaturated)
504-511 F8.6 --- FGKsgPurEW ? Purity estimator based on equivalent
width for FGK subgiant
(FGKSubgiantPurity_EW)
513 A1 --- FGKsgPur Purity-selection flag (Y/N) for FGK
subgiant (FGKSubgiantFlag_Purity)
515-522 F8.6 --- FGKsgRMSE ? Root-mean-square error of the observed vs
synthetic comparison for FGK subgiant
(FGKSubgiantRMSE)
524-531 F8.6 --- FGKsgMAD ? Median absolute deviation of the
residuals for FGK subgiant
(FGKSubgiantMAD)
533-542 F10.6 --- FGKsgChi2 ? Reduced chi-square of the observed vs
synthetic comparison for FGK subgiant
(FGKSubgiantChi2_Red)
544 A1 --- FGKsgGoF Goodness-of-fit flag (Y/N) for FGK subgiant
(FGKSubgiantFlag_GoF)
546 A1 --- FGKsgRob Final robust-line flag (Y/N), obtained by
combining the selection criteria for FGK
subgiant (FGKSubgiantRobust)
548-555 F8.6 --- FGKgDepS ? Line depth measured in the synthetic
spectrum for FGK giant (FGKGiantdepth_syn)
557-567 F11.6 0.1nm FGKgWoffS ? Wavelength offset of the synthetic line
center relative to the nominal line
wavelength for FGK giant
(FGKGiantdelwavsyn)
569-576 F8.6 --- e_FGKgDepS ? Uncertainty in the synthetic line depth
of FGKgDepS (FGKGiantdeptherrsyn)
578-585 F8.6 --- f_FGKgDepS ? Warning flag associated with the
synthetic-spectrum line measurement for FGK
giant (FGKGiantwarn_synth)
587-595 F9.6 --- FGKgDepO ? Line depth measured in the observed
spectrum for FGK giant (FGKGiantdepth_obs)
597-608 F12.6 0.1nm FGKgWoffO ? Wavelength offset of the observed line
center relative to the nominal line
wavelength for FGK giant
(FGKGiantdelwavobs)
610-617 F8.6 --- e_FGKgDepO ? Uncertainty in the observed line depth of
FGKgDepO (FGKGiantdeptherrobs)
619-627 F9.6 --- f_FGKgDepO ? Warning flag associated with the
observed-spectrum line measurement for FGK
giant (FGKGiantwarn_obs)
629 A1 --- FGKgDepth Depth-selection flag (Y/N) for FGK giant
(FGKGiantFlag_depth)
631 A1 --- FGKgSat Unsaturated-line flag (Y/N) for FGK giant
(FGKGiantFlag_Unsaturated)
633-641 F9.6 --- FGKgPurEW ? Purity estimator based on equivalent
width for FGK giant (FGKGiantPurity_EW)
643 A1 --- FGKgPur Purity-selection flag (Y/N) for FGK giant
(FGKGiantFlag_Purity)
645-653 F9.6 --- FGKgRMSE ? Root-mean-square error of the observed vs
synthetic comparison for FGK giant
(FGKGiantRMSE)
655-663 F9.6 --- FGKgMAD ? Median absolute deviation of the
residuals for FGK giant (FGKGiantMAD)
665-674 F10.6 --- FGKgChi2 ? Reduced chi-square of the observed vs
synthetic comparison for FGK giant
(FGKGiantChi2_Red)
676 A1 --- FGKgGoF Goodness-of-fit flag (Y/N) for FGK giant
(FGKGiantFlag_GoF)
678 A1 --- FGKgRob Final robust-line flag (Y/N), obtained by
combining the selection criteria for FGK
giant (FGKGiantRobust)
680-687 F8.6 --- MGDepS ? Line depth measured in the synthetic
spectrum for M giant (MGiantdepth_syn)
689-697 F9.6 0.1nm MGWoffS ? Wavelength offset of the synthetic line
center relative to the nominal line
wavelength for M giant (MGiantdelwavsyn)
699-706 F8.6 --- e_MGDepS ? Uncertainty in the synthetic line depth
of MGDepS (MGiantdeptherrsyn)
708-715 F8.6 --- f_MGDepS ? Warning flag associated with the
synthetic-spectrum line measurement for M
giant (MGiantwarn_synth)
717-725 F9.6 --- MGDepO ? Line depth measured in the observed
spectrum for M giant (MGiantdepth_obs)
727-737 F11.6 0.1nm MGWoffO ? Wavelength offset of the observed line
center relative to the nominal line
wavelength for M giant (MGiantdelwavobs)
739-746 F8.6 --- e_MGDepO ? Uncertainty in the observed line depth of
MGDepO (MGiantdeptherrobs)
748-756 F9.6 --- f_MGDepO ? Warning flag associated with the
observed-spectrum line measurement for M
giant (MGiantwarn_obs)
758 A1 --- MGDepth Depth-selection flag (Y/N) for M giant
(MGiantFlag_depth)
760 A1 --- MGSat Unsaturated-line flag (Y/N) for M giant
(MGiantFlag_Unsaturated)
762-769 F8.6 --- MGPurEW ? Purity estimator based on equivalent
width for M giant (MGiantPurity_EW)
771 A1 --- MGPur Purity-selection flag (Y/N) for M giant
(MGiantFlag_Purity)
773-780 F8.6 --- MGRMSE ? Root-mean-square error of the observed vs
synthetic comparison for M giant
(MGiantRMSE)
782-789 F8.6 --- MGMAD ? Median absolute deviation of the
residuals for M giant (MGiantMAD)
791-801 F11.6 --- MGChi2 ? Reduced chi-square of the observed vs
synthetic comparison for M giant
(MGiantChi2_Red)
803 A1 --- MGGoF Goodness-of-fit flag (Y/N) for M giant
(MGiantFlag_GoF)
805 A1 --- MGRob Final robust-line flag (Y/N), obtained by
combining the selection criteria for M
giant (MGiantRobust)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: sp/*
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 F19.13 0.1nm Wave Observed wavelength (waveobs)
21- 42 F22.18 --- Flux Normalized observed flux in either H/J/Y band
(flux)
44- 46 F3.1 --- e_Flux Uncertainty of Flux (err)
--------------------------------------------------------------------------------
Acknowledgements:
Scarlet Elgueta, sselgueta(at)gmail.com
License: CC-BY-4.0 [see https://spdx.org/licenses/]
(End) Luc Trabelsi [CDS] 23-Apr-2026