J/A+A/687/A303 Line list for convective blueshift analysis (Meunier+, 2024)
Confrontation between modelled solar integrated observables and
direct observations. I. Radial velocities and convective blueshift.
Meunier N., Lagrange A.-M., Dumusque X., Sulis S.
<Astron. Astrophys. 687, A303 (2024)>
=2024A&A...687A.303M 2024A&A...687A.303M (SIMBAD/NED BibCode)
ADC_Keywords: Sun ; Atomic physics ; Spectroscopy
Keywords: techniques: spectroscopic - Sun: activity - Sun: faculae, plages -
Sun: granulation - planets and satellites: detection - stars: activity
Abstract:
Stellar variability strongly impacts the search for low-mass
exoplanets with radial velocity techniques. Two types of planet-free
time series can be used to quantify this impact: models and direct
solar observations after a subtraction of the Solar System planetary
contribution. Making a comparison among these approaches is necessary
to improve the models, which can then be used for blind tests across a
broad range of conditions.
Our objective is therefore to validate the amplitude of the convective
blueshift in plages used in our previous works, particularly in blind
tests, with HARPS-N solar data.
We applied our model to the structures observed at the time of HARPS-N
observations and established a direct comparison between the radial
velocity time series. To complete our diagnosis, we also studied the
observed radial velocities separately for each diffraction order
derived from the individual cross-correlation functions, as well as
our line-by-line radial velocities.
We find that our previous model had been underestimating the amplitude
of the convective blueshift inhibition by a factor of about 2. A
direct estimation of the convective blueshift in the spectra, which is
shown to be correlated with the plage filling factor, allows us to
explain the difference with previous estimations obtained with
MDI/SOHO Dopplergrams, based on the specific properties of the Ni line
used in this mission. In addition, we identified several instrumental
systematics, in particular, the presence of a 2m/s peak-to-peak
signal with a period of about 200 days in radial velocity and
bisector. This signal could be due to periodic detector warmups, a
systematic dependence of the long-term trend on wavelength that is
possibly related to the variability of the continuum over time, and/or
an offset in radial velocity after the interruption of several months
in October 2017.
A large amplitude in the convective blueshift inhibition of (360m/s,
namely twice more than in our previous works) must be used when
building synthetic times series for blind tests. The presence of
instrumental systematics should also be taken into account when using
sophisticated methods based on line properties to mitigate stellar
activity when searching for very weak signals.
Description:
Line used in the convective blueshift analysis.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablef1.dat 52 2518 Line used in the convective blueshift analysis
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Byte-by-byte Description of file: tablef1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Element Element and ionisation
8- 16 F9.4 0.1nm lambda1 Line wavelength
23 I1 --- r_lambda1 Wavelength references (1)
28- 36 F9.4 0.1nm lambda2 Line wavelength
41- 42 I2 --- r_lambda2 Wavelength references (2)
48- 52 F5.3 --- Linedepth ?=- Average line depth, - if not used (3)
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Note (1): References of the first set of wavelengths as follows:
1 = Dravins, 2008A&A...492..199D 2008A&A...492..199D
2 = Nave et al., 1994ApJS...94..221N 1994ApJS...94..221N
3 = Litzen et al., 1993PhyS...47..628L 1993PhyS...47..628L
Note (2): References of the second set of wavelengths from VALD as follows:
4 = Kurucz, 2014, http://kurucz.harvard.edu/atoms/
5 = Bard & Kock, 1994A&A...282.1014B 1994A&A...282.1014B
6 = Fuhr et al., 1988JPCRD..17S....F 1988JPCRD..17S....F
7 = O'Brian et al., 1991JOSAB...8.1185O 1991JOSAB...8.1185O
8 = Kurucz , 013, http://kurucz.harvard.edu/atoms/
9 = Blackwell et al., 1980A&A....81..340B 1980A&A....81..340B
10 = Kurucz, 2008) http://kurucz.harvard.edu/atoms/
11 = Wood et al., 2014ApJS..211...20W 2014ApJS..211...20W
12 = Kurucz, 2016, http://kurucz.harvard.edu/atoms/
13 = Karlsson & Litzen, 2000JPhB...33.2929K 2000JPhB...33.2929K
Note (3): Line depths are averages over all selected spectra. Line depths
below 0.001 are arbitrarily set to 0. '-' indicates that the line
was eliminated during the selection process.
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Acknowledgements:
Nadege Meunier, nadege.meunier(at)univ-grenoble-alpes.fr
(End) Patricia Vannier [CDS] 29-Apr-2024