J/A+A/700/A177 Proxima + Gl581 activity-sensitive lines (Gomes da Silva+, 2025)
Blind search for activity-sensitive lines in the near-infrared using HARPS and
NIRPS observations of Proxima and Gl 581.
Gomes da Silva J., Delgado-Mena E., Santos N.C., Monteiro T., Larue P.,
Suarez Mascareno A., Delfosse X., Mignon L., Artigau E., Nari N., Abreu M.,
Aguiar L.A.J., Al Moulla K., Allain G., Allart R., Arial T., Auger H.,
Baron F., Barros C.C.S., Bazinet L., Benneke B., Blind N., Bohlender D.,
Boisse I., Bonfils X., Boucher A., Bouchy F., Bourrier V., Bovay S.,
Branco P., Broeg C., Brousseau D., Bruniquel V., Bryan M., Cabral A.,
Cadieux C., Canto Martins L.B., Carmona A., Carteret Y., Challita Z.,
Chazelas B., Cloutier R., Coelho J., Cointepas M., Conod U., Cook J.N.,
Costa Silva A.R., Cowan B.N., Cristo E., Darveau-Bernier A., Dauplaise L.,
de Lima Gomes R., De Medeiros J.R., Delisle J.-B., Doshi D., Doyon R.,
Dumusque X., Ehrenreich D., Figueira P., Dasaev Fontinele O., Forveille T.,
Frensch G.C.Y., Gagne J., Genest F., Genolet L., Gonzalez Hernandez I.J.,
Glover J., Gracia Temich F., Grieves N., Gromek N., Hernandez O.,
Hobson J.M., Hoeijmakers H.J., Hubin N., Jahandar F., Jayawardhana R.,
Kaeufl H.-U., Kerley D., Kolb J., Krishnamurthy V., Kung B., L'Heureux A.,
Lafreniere D., Lamontagne P., de Castro Leao I., Leath H., Lim O.,
Lipper J., Lo Curto G., Lovis C., Malo L., Martins M.A., Matthews J.,
Mayer J.-S., Melo C., Messamah L., Messias S.Y., Metchev S., Moranta L.,
Mordasini C., Mounzer D., Mraz G., Nielsen D.L., Osborn A., Otegi J.,
Ouellet M., Parc L., Pasquini L., Passegger M.V., Pelletier S., Pepe F.,
Peroux C., Piaulet-Ghorayeb C., Plotnykov M., Pompei E.,
Poulin-Girard A.-S., Rasilla J.L., Rebolo R., Reshetov V., Rowe J.,
Saint-Antoine J., Sarajlic M., Saviane I., Schnell R., Segovia A.,
Segransan D., Seidel J., Silber A., Sinclair P., Sordet M., Sosnowska D.,
Srivastava A., Stefanov K.A., Teixeira A.M., Thibault S., Udry S.,
Valencia D., Vallee P., Vandal T., Vaulato V., Wade G.,
Joost Wardenier P., Wehbe B., Weisserman D., Wevers I., Wildi F.,
Yariv V., Zins G.
<Astron. Astrophys. 700, A177 (2025)>
=2025A&A...700A.177G 2025A&A...700A.177G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, G-type ; Spectroscopy ; Infrared ; Optical
Keywords: methods: observational - techniques: spectroscopic - catalogs -
planets and satellites: detection - stars: activity - stars: low-mass
Abstract:
Stellar activity variability is one of the main obstacles to the
detection of Earth-like planets using the radial velocity (RV) method.
The aim of this work is to measure the effect of activity in the
spectra of M dwarfs and detect activity-sensitive lines in the
near-infrared (NIR) to help improve exoplanet detection and
characterisation and contribute to further stellar activity analysis
in the NIR.
We took advantage of the simultaneous observations of HARPS and the
newly commissioned NIRPS spectrograph to carry out a blind search of
the most activity-sensitive spectral lines in the NIR using NIRPS
spectra and known activity indicators in the optical from HARPS as a
reference. We analysed the spectra of Proxima (M5.5V) and Gl 581
(M3V), two M dwarfs with different activity levels and internal
structures. Spectral lines were identified for both stars and their
profiles were fitted using different models.
We found hundreds of lines sensitive to activity for both stars; the
Proxima spectra were more affected. For Proxima, around 32% of the
identified lines can be used to measure the rotation period of the
star, while for Gl 581 the numbers drops to 1%. The fraction of lines
sensitive to activity increases with increasing line depth for both
stars. A list of 17 lines with rotation period detection for both
stars is provided.
Stellar activity is able to affect a significant number of spectral
lines in the NIR, and methods should be developed to mitigate those
effects at the spectral level. The line distortions detected here are
expected to come mainly from the flux effect due to temperature
contrasts between active regions and the quiet photosphere; however,
we cannot rule out the possibility that core-emission from
chromospheric activity or Zeeman splitting are also affecting some
lines. The new line lists presented here can be used to improve the RV
extraction and the detection of RV variability due to stellar activity
signals, and to help false positive detection and the modelling of
activity variability, thereby enhancing exoplanet detection in the
NIR.
Description:
Line lists with the correlation and period detection analysis.
We curated a list of 17 spectral lines with rotation detection for
both stars that can used as potential NIR activity proxies for M
dwarfs. These lists can be used to further develop techniques to
analyse and mitigate the effects of stellar activity in the NIR
spectra of M dwarfs. Furthermore, these activity-sensitive lines can
be used to reduce the effects of stellar activity on NIR RV by
excluding them from CCF masks, LBL analysis, and template matching
methods. Additionally, they can also be used to detect rotation
periods and identify false-positive exoplanet detections.
Objects:
---------------------------------------------------
RA (2000) DE Designation(s)
---------------------------------------------------
15 19 26.82 -07 43 20.1 Gl 581 = HIP 74995
14 29 42.94 -62 40 46.1 Proxima = alf Cen C
---------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
gl581.dat 946 2021 Line of Gl581 (table E1)
prox.dat 946 2767 Line of Proxima (table E1)
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Byte-by-byte Description of file: gl581.dat prox.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 F18.12 0.1nm ctr Median of the fitted line centre
time series (ctr)
20- 37 F18.16 0.1nm e_ctr Median of the fitted line centre
uncertainties time series (ctr_e)
39- 56 F18.16 0.1nm s_ctr Standard deviation of the fitted line
centre time series (ctr_std)
58- 76 F19.16 km/s FWHM Median of the fitted FWHM time series
(fwhm)
78- 95 F18.16 km/s e_FWHM Median of the fitted FWHM uncertainties
time series (fwhm_e)
97-114 F18.16 km/s s_FWHM Standard deviation of the fitted FWHM
time series (fwhm_std)
116-133 F18.16 --- Depth Median of the fitted line depth time
series in units of fraction of the
normalised continuum (depth)
135-152 F18.16 --- e_Depth Median of the fitted line depth
uncertainties time series in units of
fraction of the normalised continuum
(depth_e)
154-171 F18.16 --- s_Depth Standard deviation of the fitted line
depth time series in units of fraction
of the normalised continuum (depth_std)
173-194 E22.16 --- rho-ctr-F-N Pearson correlation coefficient between
the line centre and NIRPS CCF FWHM
(rhoctrfwhm_nirps)
196-214 F19.16 --- rho-ctr-Ha Pearson correlation coefficient between
the line centre and the Halpha06 index
(rhoctrha)
216-235 E20.16 --- rho-ctr-Na Pearson correlation coefficient between
the line centre and the NaI index
(rhoctrna)
237-257 E21.16 --- rho-ctr-BERV Pearson correlation coefficient between
the line centre and BERV (rhoctrberv)
259-277 F19.16 --- rho-F-F-N Pearson correlation coefficient between
the line FWHM and NIRPS CCF FWHM
(rhofwhmfwhm_nirps)
279-297 F19.16 --- rho-F-Ha Pearson correlation coefficient between
the line FWHM and the Halpha06 index
(rhofwhmha)
299-320 E22.16 --- rho-F-Na Pearson correlation coefficient between
the line FWHM and the NaI index
(rhofwhmna)
322-343 E22.16 --- rho-F-BERV Pearson correlation coefficient between
the line FWHM and BERV (rhofwhmberv)
345-363 F19.16 --- rho-D-F-N Pearson correlation coefficient between
the line depth and NIRPS CCF FWHM
(rhodepthfwhm_nirps)
365-386 E22.16 --- rho-D-Ha Pearson correlation coefficient between
the line depth and the Halpha06 index
(rhodepthha)
388-408 E21.16 --- rho-D-Na Pearson correlation coefficient between
the line depth and the NaI index
(rhodepthna)
410-428 F19.16 --- rho-D-BERV Pearson correlation coefficient between
the line depth and BERV (rhodepthberv)
430-451 E22.16 --- pv-ctr-F-N p-value of the correlation between the
line centre and the NIRPS CCF FWHM
(pvctrfwhm_nirps)
453-474 E22.16 --- pv-ctr-Ha p-value of the correlation between the
line centre and the Halpha06 index
(pvctrha)
476-497 E22.16 --- pv-ctr-Na p-value of the correlation between the
line centre and the NaI index
(pvctrna)
499-520 E22.16 --- pv-F-F-N p-value of the correlation between the
line FWHM and NIRPS CCF FWHM
(pvfwhmfwhm_nirps)
522-543 E22.16 --- pv-F_Ha p-value of the correlation between the
line FWHM and the Halpha06 index
(pvfwhmha)
545-566 E22.16 --- pv-F-Na p-value of the correlation between the
line FWHM and the NaI index (pvfwhmna)
568-589 E22.16 --- pv-D-F-N p-value of the correlation between the
line depth and the NIRPS CCF FWHM
(pvdepthfwhm_nirps)
591-612 E22.16 --- pv-D-Ha p-value of the correlation between the
line depth and the Halpha06 index
(pvdepthha)
614-635 E22.16 --- pv-D-Na p-value of the correlation between the
line depth and the NaI index
(pvdepthna)
637-655 F19.16 --- rho-pEW-Act Pearson correlation coefficient between
the best pEW and the best activity index
(rhopewact)
657-678 E22.16 --- pv-pEW-Act p-value of the correlation between the
best pEW and the best activity index
(pvpewact)
680-701 E22.16 --- rho-pEW-BERV Pearson correlation coefficient between
the best pEW and BERV (rhopewberv)
703-708 A6 --- bestpEW pEW parameter responsible for the
correlation in rhopewact (best_pew)
710-723 A14 --- bestAct Activity index responsible for the
correlation in rhopewact (best_act)
725-744 F20.16 km/s bandpass Central bandpass used to compute
best_pew (bandpass)
746-763 F18.16 km/s bandpass-c20 Central bandpass obtained from using
Cretignier et al. (2020A&A...633A..76C 2020A&A...633A..76C)
line identification method
(bandpass_c20)
765-784 F20.16 d ctr-Per ? Period detected using line centre
time series (ctr_per)
786-807 E22.16 --- ctr-FAP ? FAP of the period detected using line
centre time series (ctr_fap)
809-828 F20.16 d FWHM-Per ? Period detected using line FWHM
time series (fwhm_per)
830-851 E22.16 --- FWHM-FAP ? FAP of the period detected using
line FWHM time series (fwhm_fap)
853-872 F20.16 d Depth-Per ? Period detected using line depth
time series (depth_per)
874-895 E22.16 --- Depth-FAP ? FAP of the period detected using
line depth time series (depth_fap)
897-914 F18.14 d pEW-Per ? Period detected using the best pEW
time series (pew_per)
916-937 E22.16 --- pEW-FAP ? FAP of the period detected using
the best pEW time series (pew_fap)
939-944 A6 d bestpEW-Per ? pEW parameter used in pew_per
(bestpewper)
946 I1 --- Flag [0/3]? Flag (flag) (1)
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Note (1): Falg as follows:
1 = correlation only
2 = rotation only
3 = correlation and rotation
0 = no activity detection
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Acknowledgements:
Joao Gomes da Silva, joao.silva(at)astro.up.pt
(End) Patricia Vannier [CDS] 21-Jul-2025