Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun

X. Dumusque; M. Cretignier; D. Sosnowska; N. Buchschacher; C. Lovis; D. F. Phillips; F. Pepe; F. Alesina; L. A. Buchhave; J. Burnier; M. Cecconi; H. M. Cegla; R. Cloutier; A. Collier Cameron; R. Cosentino; A. Ghedina; M. González; R. D. Haywood; D. W. Latham; M. Lodi; M. López-Morales; J. Maldonado; L. Malavolta; G. Micela; E. Molinari; A. Mortier; H. Pérez Ventura; M. Pinamonti; E. Poretti; K. Rice; L. Riverol; C. Riverol; J. San Juan; D. Ségransan; A. Sozzetti; S. J. Thompson; S. Udry; T. G. Wilson

doi:10.1051/0004-6361/202039350

Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun

X. Dumusque^*, M. Cretignier, D. Sosnowska, N. Buchschacher, C. Lovis, D. F. Phillips, F. Pepe, F. Alesina, L. A. Buchhave, J. Burnier, M. Cecconi, H. M. Cegla, R. Cloutier, A. Collier Cameron, R. Cosentino, A. Ghedina, M. González, R. D. Haywood, D. W. Latham, M. LodiM. López-Morales, J. Maldonado, L. Malavolta, G. Micela, E. Molinari, A. Mortier, H. Pérez Ventura, M. Pinamonti, E. Poretti, K. Rice, L. Riverol, C. Riverol, J. San Juan, D. Ségransan, A. Sozzetti, S. J. Thompson, S. Udry, T. G. Wilson

^*Corresponding author for this work

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

24 Citations (Scopus)

Abstract

Context. The solar telescope connected to HARPS-N has been observing the Sun since the summer of 2015. Such a high-cadence, long-baseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. On the instrumental side, this data set allowed us to detect sub- m s^-1 systematics that needed to be corrected for.

Aims. The goals of this manuscript are to (i) present a new data reduction software for HARPS-N, (ii) demonstrate the improvement brought by this new software during the first three years of the HARPS-N solar data set, and (iii) release all the obtained solar products, from extracted spectra to precise radial velocities.

Methods. To correct for the instrumental systematics observed in the data reduced with the current version of the HARPS-N data reduction software (DRS version 3.7), we adapted the newly available ESPRESSO DRS (version 2.2.3) to HARPS-N and developed new optimised recipes for the spectrograph. We then compared the first three years of HARPS-N solar data reduced with the current and new DRS.

Results. The most significant improvement brought by the new DRS is a strong decrease in the day-to-day radial-velocity scatter, from 1.27 to 1.07 m s^-1; this is thanks to a more robust method to derive wavelength solutions, but also to the use of calibrations closer in time. The newly derived solar radial-velocities are also better correlated with the chromospheric activity level of the Sun in the long term, with a Pearson correlation coefficient of 0.93 compared to 0.77 before, which is expected from our understanding of stellar signals. Finally, we also discuss how HARPS-N spectral ghosts contaminate the measurement of the calcium activity index, and we present an efficient technique to derive an index free of instrumental systematics.

Conclusions. This paper presents a new data reduction software for HARPS-N and demonstrates its improvements, mainly in terms of radial-velocity precision, when applied to the first three years of the HARPS-N solar data set. Those newly reduced solar data, representing an unprecedented time series of 34 550 high-resolution spectra and precise radial velocities, are released alongside this paper. Those data are crucial to understand stellar activity signals in solar-type stars further and develop the mitigating techniques that will allow us to detect other Earths.

Original language	English
Article number	A103
Number of pages	19
Journal	Astronomy and Astrophysics
Volume	648
DOIs	https://doi.org/10.1051/0004-6361/202039350
Publication status	Published - 21 Apr 2021

Bibliographical note

Funding Information:
Acknowledgements. XD is grateful to The Branco Weiss Fellowship-Society in Science for its financial support. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 851555/SCORE). ACC acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. This work has been carried out in the framework of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). AM acknowledges support from the senior Kavli Institute Fellowships. This research used the DACE platform developed in the frame of PlanetS (https://dace.unige.ch). This work was performed under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (RDH).

Publisher Copyright:
© ESO 2021.

Keywords

Astronomical databases: miscellaneous
Instrumentation: spectrographs
Methods: data analysis
Planets and satellites: detection
Sun: activity
Techniques: radial velocities

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1051/0004-6361/202039350

Cite this

Dumusque, X., Cretignier, M., Sosnowska, D., Buchschacher, N., Lovis, C., Phillips, D. F., Pepe, F., Alesina, F., Buchhave, L. A., Burnier, J., Cecconi, M., Cegla, H. M., Cloutier, R., Collier Cameron, A., Cosentino, R., Ghedina, A., González, M., Haywood, R. D., Latham, D. W., ... Wilson, T. G. (2021). Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun. Astronomy and Astrophysics, 648, Article A103. https://doi.org/10.1051/0004-6361/202039350

@article{8595ec7904fc4ee1b0e309c3be94cb10,

title = "Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun",

abstract = "Context. The solar telescope connected to HARPS-N has been observing the Sun since the summer of 2015. Such a high-cadence, long-baseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. On the instrumental side, this data set allowed us to detect sub- m s-1 systematics that needed to be corrected for. Aims. The goals of this manuscript are to (i) present a new data reduction software for HARPS-N, (ii) demonstrate the improvement brought by this new software during the first three years of the HARPS-N solar data set, and (iii) release all the obtained solar products, from extracted spectra to precise radial velocities. Methods. To correct for the instrumental systematics observed in the data reduced with the current version of the HARPS-N data reduction software (DRS version 3.7), we adapted the newly available ESPRESSO DRS (version 2.2.3) to HARPS-N and developed new optimised recipes for the spectrograph. We then compared the first three years of HARPS-N solar data reduced with the current and new DRS. Results. The most significant improvement brought by the new DRS is a strong decrease in the day-to-day radial-velocity scatter, from 1.27 to 1.07 m s-1; this is thanks to a more robust method to derive wavelength solutions, but also to the use of calibrations closer in time. The newly derived solar radial-velocities are also better correlated with the chromospheric activity level of the Sun in the long term, with a Pearson correlation coefficient of 0.93 compared to 0.77 before, which is expected from our understanding of stellar signals. Finally, we also discuss how HARPS-N spectral ghosts contaminate the measurement of the calcium activity index, and we present an efficient technique to derive an index free of instrumental systematics. Conclusions. This paper presents a new data reduction software for HARPS-N and demonstrates its improvements, mainly in terms of radial-velocity precision, when applied to the first three years of the HARPS-N solar data set. Those newly reduced solar data, representing an unprecedented time series of 34 550 high-resolution spectra and precise radial velocities, are released alongside this paper. Those data are crucial to understand stellar activity signals in solar-type stars further and develop the mitigating techniques that will allow us to detect other Earths.",

keywords = "Astronomical databases: miscellaneous, Instrumentation: spectrographs, Methods: data analysis, Planets and satellites: detection, Sun: activity, Techniques: radial velocities",

author = "X. Dumusque and M. Cretignier and D. Sosnowska and N. Buchschacher and C. Lovis and Phillips, {D. F.} and F. Pepe and F. Alesina and Buchhave, {L. A.} and J. Burnier and M. Cecconi and Cegla, {H. M.} and R. Cloutier and {Collier Cameron}, A. and R. Cosentino and A. Ghedina and M. Gonz{\'a}lez and Haywood, {R. D.} and Latham, {D. W.} and M. Lodi and M. L{\'o}pez-Morales and J. Maldonado and L. Malavolta and G. Micela and E. Molinari and A. Mortier and {P{\'e}rez Ventura}, H. and M. Pinamonti and E. Poretti and K. Rice and L. Riverol and C. Riverol and {San Juan}, J. and D. S{\'e}gransan and A. Sozzetti and Thompson, {S. J.} and S. Udry and Wilson, {T. G.}",

note = "Funding Information: Acknowledgements. XD is grateful to The Branco Weiss Fellowship-Society in Science for its financial support. This project has received funding from the European Research Council (ERC) under the European Union{\textquoteright}s Horizon 2020 research and innovation programme (grant agreement No 851555/SCORE). ACC acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. This work has been carried out in the framework of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). AM acknowledges support from the senior Kavli Institute Fellowships. This research used the DACE platform developed in the frame of PlanetS (https://dace.unige.ch). This work was performed under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (RDH). Publisher Copyright: {\textcopyright} ESO 2021.",

year = "2021",

month = apr,

day = "21",

doi = "10.1051/0004-6361/202039350",

language = "English",

volume = "648",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

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Dumusque, X, Cretignier, M, Sosnowska, D, Buchschacher, N, Lovis, C, Phillips, DF, Pepe, F, Alesina, F, Buchhave, LA, Burnier, J, Cecconi, M, Cegla, HM, Cloutier, R, Collier Cameron, A, Cosentino, R, Ghedina, A, González, M, Haywood, RD, Latham, DW, Lodi, M, López-Morales, M, Maldonado, J, Malavolta, L, Micela, G, Molinari, E, Mortier, A, Pérez Ventura, H, Pinamonti, M, Poretti, E, Rice, K, Riverol, L, Riverol, C, San Juan, J, Ségransan, D, Sozzetti, A, Thompson, SJ, Udry, S & Wilson, TG 2021, 'Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun', Astronomy and Astrophysics, vol. 648, A103. https://doi.org/10.1051/0004-6361/202039350

TY - JOUR

T1 - Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun

AU - Dumusque, X.

AU - Cretignier, M.

AU - Sosnowska, D.

AU - Buchschacher, N.

AU - Lovis, C.

AU - Phillips, D. F.

AU - Pepe, F.

AU - Alesina, F.

AU - Buchhave, L. A.

AU - Burnier, J.

AU - Cecconi, M.

AU - Cegla, H. M.

AU - Cloutier, R.

AU - Collier Cameron, A.

AU - Cosentino, R.

AU - Ghedina, A.

AU - González, M.

AU - Haywood, R. D.

AU - Latham, D. W.

AU - Lodi, M.

AU - López-Morales, M.

AU - Maldonado, J.

AU - Malavolta, L.

AU - Micela, G.

AU - Molinari, E.

AU - Mortier, A.

AU - Pérez Ventura, H.

AU - Pinamonti, M.

AU - Poretti, E.

AU - Rice, K.

AU - Riverol, L.

AU - Riverol, C.

AU - San Juan, J.

AU - Ségransan, D.

AU - Sozzetti, A.

AU - Thompson, S. J.

AU - Udry, S.

AU - Wilson, T. G.

N1 - Funding Information: Acknowledgements. XD is grateful to The Branco Weiss Fellowship-Society in Science for its financial support. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 851555/SCORE). ACC acknowledges support from the Science and Technology Facilities Council (STFC) consolidated grant number ST/R000824/1. This work has been carried out in the framework of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). AM acknowledges support from the senior Kavli Institute Fellowships. This research used the DACE platform developed in the frame of PlanetS (https://dace.unige.ch). This work was performed under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute (RDH). Publisher Copyright: © ESO 2021.

PY - 2021/4/21

Y1 - 2021/4/21

N2 - Context. The solar telescope connected to HARPS-N has been observing the Sun since the summer of 2015. Such a high-cadence, long-baseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. On the instrumental side, this data set allowed us to detect sub- m s-1 systematics that needed to be corrected for. Aims. The goals of this manuscript are to (i) present a new data reduction software for HARPS-N, (ii) demonstrate the improvement brought by this new software during the first three years of the HARPS-N solar data set, and (iii) release all the obtained solar products, from extracted spectra to precise radial velocities. Methods. To correct for the instrumental systematics observed in the data reduced with the current version of the HARPS-N data reduction software (DRS version 3.7), we adapted the newly available ESPRESSO DRS (version 2.2.3) to HARPS-N and developed new optimised recipes for the spectrograph. We then compared the first three years of HARPS-N solar data reduced with the current and new DRS. Results. The most significant improvement brought by the new DRS is a strong decrease in the day-to-day radial-velocity scatter, from 1.27 to 1.07 m s-1; this is thanks to a more robust method to derive wavelength solutions, but also to the use of calibrations closer in time. The newly derived solar radial-velocities are also better correlated with the chromospheric activity level of the Sun in the long term, with a Pearson correlation coefficient of 0.93 compared to 0.77 before, which is expected from our understanding of stellar signals. Finally, we also discuss how HARPS-N spectral ghosts contaminate the measurement of the calcium activity index, and we present an efficient technique to derive an index free of instrumental systematics. Conclusions. This paper presents a new data reduction software for HARPS-N and demonstrates its improvements, mainly in terms of radial-velocity precision, when applied to the first three years of the HARPS-N solar data set. Those newly reduced solar data, representing an unprecedented time series of 34 550 high-resolution spectra and precise radial velocities, are released alongside this paper. Those data are crucial to understand stellar activity signals in solar-type stars further and develop the mitigating techniques that will allow us to detect other Earths.

AB - Context. The solar telescope connected to HARPS-N has been observing the Sun since the summer of 2015. Such a high-cadence, long-baseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. On the instrumental side, this data set allowed us to detect sub- m s-1 systematics that needed to be corrected for. Aims. The goals of this manuscript are to (i) present a new data reduction software for HARPS-N, (ii) demonstrate the improvement brought by this new software during the first three years of the HARPS-N solar data set, and (iii) release all the obtained solar products, from extracted spectra to precise radial velocities. Methods. To correct for the instrumental systematics observed in the data reduced with the current version of the HARPS-N data reduction software (DRS version 3.7), we adapted the newly available ESPRESSO DRS (version 2.2.3) to HARPS-N and developed new optimised recipes for the spectrograph. We then compared the first three years of HARPS-N solar data reduced with the current and new DRS. Results. The most significant improvement brought by the new DRS is a strong decrease in the day-to-day radial-velocity scatter, from 1.27 to 1.07 m s-1; this is thanks to a more robust method to derive wavelength solutions, but also to the use of calibrations closer in time. The newly derived solar radial-velocities are also better correlated with the chromospheric activity level of the Sun in the long term, with a Pearson correlation coefficient of 0.93 compared to 0.77 before, which is expected from our understanding of stellar signals. Finally, we also discuss how HARPS-N spectral ghosts contaminate the measurement of the calcium activity index, and we present an efficient technique to derive an index free of instrumental systematics. Conclusions. This paper presents a new data reduction software for HARPS-N and demonstrates its improvements, mainly in terms of radial-velocity precision, when applied to the first three years of the HARPS-N solar data set. Those newly reduced solar data, representing an unprecedented time series of 34 550 high-resolution spectra and precise radial velocities, are released alongside this paper. Those data are crucial to understand stellar activity signals in solar-type stars further and develop the mitigating techniques that will allow us to detect other Earths.

KW - Astronomical databases: miscellaneous

KW - Instrumentation: spectrographs

KW - Methods: data analysis

KW - Planets and satellites: detection

KW - Sun: activity

KW - Techniques: radial velocities

UR - http://www.scopus.com/inward/record.url?scp=85104681159&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/202039350

DO - 10.1051/0004-6361/202039350

M3 - Article

AN - SCOPUS:85104681159

SN - 0004-6361

VL - 648

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A103

ER -

Three years of HARPS-N high-resolution spectroscopy and precise radial velocity data for the Sun

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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