Jean-François Donati
Centre national de la recherche scientifique
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Featured researches published by Jean-François Donati.
Proceedings of SPIE | 2014
Étienne Artigau; Driss Kouach; Jean-François Donati; René Doyon; X. Delfosse; Sébastien Baratchart; Marielle Lacombe; Claire Moutou; Patrick Rabou; L. Parès; Yoan Micheau; Simon Thibault; Vladimir Reshetov; Bruno Dubois; Olivier Hernandez; Philippe Vallee; Shiang-Yu Wang; François Dolon; F. Pepe; F. Bouchy; Nicolas Striebig; François Hénault; David Loop; Leslie Saddlemyer; Gregory Barrick; Tom Vermeulen; M. Dupieux; G. Hébrard; I. Boisse; Eder Martioli
SPIRou is a near-IR echelle spectropolarimeter and high-precision velocimeter under construction as a next- generation instrument for the Canada-France-Hawaii-Telescope. It is designed to cover a very wide simultaneous near-IR spectral range (0.98-2.35 μm) at a resolving power of 73.5K, providing unpolarized and polarized spectra of low-mass stars at a radial velocity (RV) precision of 1m/s. The main science goals of SPIRou are the detection of habitable super-Earths around low-mass stars and the study of stellar magnetism of star at the early stages of their formation. Following a successful final design review in Spring 2014, SPIRou is now under construction and is scheduled to see first light in late 2017. We present an overview of key aspects of SPIRou’s optical and mechanical design.
Proceedings of SPIE | 2012
Simon Thibault; Patrick Rabou; Jean-François Donati; Pierre Desaulniers; Xavier Dallaire; Étienne Artigau; F. Pepe; Yoan Micheau; Philippe Vallee; Greg Barrick; Vlad Reshetov; Olivier Hernandez; Leslie Saddlemyer; John Pazder; L. Parès; René Doyon; X. Delfosse; Driss Kouach; David Loop
SPIRou is a near-infrared, echelle spectropolarimeter/velocimeter under design for the 3.6m Canada-France-Hawaii Telescope (CFHT) on Mauna Kea, Hawaii. The unique scientific capabilities and technical design features are described in the accompanying (eight) papers at this conference. In this paper we focus on the lens design of the optical spectrograph. The SPIROU spectrograph is a near infrared fiber fed double pass cross dispersed spectrograph. The cryogenic spectrograph is connected with the Cassegrain unit by the two science fibers. It is also fed by the fiber coming from the calibration box and RV reference module of the instrument. It includes 2 off-axis parabolas (1 in double pass), an echelle grating, a train of cross disperser prisms (in double pass), a flat folding mirror, a refractive camera and a detector. This paper describes the optical design of the spectrograph unit and estimates the performances. In particular, the echelle grating options are discussed as the goal grating is not available from the market.
Proceedings of SPIE | 2012
Gregory Barrick; Tom Vermeulen; Sébastien Baratchart; Vladimir Reshetov; Shiang-Yu Wang; François Dolon; Olivier Hernandez; F. Pepe; F. Bouchy; Jennifer Dunn; M. Dupieux; Gérard Gallou; Marie Larrieu; Alexandre Fonteneau; François Moreau; F. Wildi; L. Parès; James N. Thomas; Chi-Hung Yan; René Doyon; Jean-François Donati; Philippe Vallee; Étienne Artigau; X. Delfosse; Patrick Rabou; Simon Thibault; Driss Kouach; David Loop
SPIRou is a near-IR (0.98-2.35μm), echelle spectropolarimeter / high precision velocimeter being designed as a nextgeneration instrument for the 3.6m Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, with the main goals of detecting Earth-like planets around low-mass stars and magnetic fields of forming stars. The unique scientific and technical capabilities of SPIRou are described in a series of eight companion papers. In this paper, the means of controlling the instrument are discussed. Most of the instrument control is fairly normal, using off-the-shelf components where possible and reusing already available code for these components. Some aspects, however, are more challenging. In particular, the paper will focus on the challenges of doing fast (50 Hz) guiding with 30 mas repeatability using the object being observed as a reference and on thermally stabilizing a large optical bench to a very high precision (~1 mK).μ
Proceedings of SPIE | 2012
L. Parès; Jean-François Donati; M. Dupieux; T. Gharsa; Yoan Micheau; M. Bouye; Bruno Dubois; Gérard Gallou; Driss Kouach; Gregory Barrick; Shiang-Yu Wang
SPIRou is a near-IR (0.98-2.35μm), echelle spectropolarimeter / high precision velocimeter being designed as a nextgeneration instrument for the 3.6m Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, with the main goal of detecting Earth-like planets around low-mass stars and magnetic fields of forming stars. The unique scientific and technical capabilities of SPIRou are described in a series of seven companion papers. In this paper, the Front End of the instrument is presented. Positioned at the Cassegrain Focal plane of the telescope, the front end is constituted of an atmospheric dispersion corrector, a field viewer with an image stabilization unit (0.03 arc seconds RMS stabilization goal), a calibration wheel and an achromatic polarimeter unit based on Fresnel Rhombs. The polarimeter permits the circular and linear polarization analysis. The retardance of the Fresnel rhombs is nominal to better than 0.5% in the whole spectral domain. The evaluation and the reduction of the thermal background of the Front end is a challenging part of the instrument.
Proceedings of SPIE | 2012
Yoan Micheau; F. Bouchy; F. Pepe; Bruno Chazelas; Driss Kouach; L. Parès; Jean-François Donati; Gregory Barrick; Patrick Rabou; Simon Thibault; Leslie Saddlemyer; Sandrine Perruchot; X. Delfosse; Nicolas Striebig; Gérard Gallou; David Loop; John Pazder
SPIRou is a near-IR (0.98-2.35μm), echelle spectropolarimeter / high precision velocimeter being designed as a next-generation instrument for the 3.6m Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, with the main goal of detecting Earth-like planets around low mass stars and magnetic fields of forming stars. The unique scientific and technical capabilities of SPIRou are described in a series of seven companion papers. In this paper, the fiber links which connects the polarimeter unit to the cryogenic spectrograph unit (35 meter apart) are described. The pupil slicer which forms a slit compatible with the spectrograph entrance specifications is also discussed in this paper. Some challenging aspects are presented. In particular this paper will focus on the manufacturing of 35 meter fibers with a very low loss attenuation (< 13dB/km) in the non-usual fiber spectral domain from 0.98 μm to 2.35 μm. Other aspects as the scrambling performance of the fiber links to reach high accuracy radial velocity measurements (1m/s) and the design of the pupil slicer exposed at a cryogenic and vacuum environment will be discussed.
Proceedings of SPIE | 2012
Étienne Artigau; F. Bouchy; X. Delfosse; Xavier Bonfils; Jean-François Donati; P. Figueira; Karun Thanjavur; David Lafrenière; René Doyon; Christian Surace; Claire Moutou; I. Boisse; Leslie Saddlemyer; David Loop; Driss Kouach; F. Pepe; Christophe Lovis; Olivier Hernandez; Shiang-Yu Wang
SPIRou is a near-infrared, echelle spectropolarimeter/velocimeter under design for the 3.6m Canada-France- Hawaii Telescope (CFHT) on Mauna Kea, Hawaii. The unique scientific capabilities and technical design features are described in the accompanying papers at this conference. In this paper we focus on the data reduction software (DRS) and the data simulation tool. The SPIRou DRS builds upon the experience of the existing SOPHIE, HARPS and ESPADONS spectrographs; class-leaders instruments for high-precision RV measurements and spectropolarimetry. While SPIRou shares many characteristics with these instruments, moving to the near- infrared domain brings specific data-processing challenges: the presence of a large number of telluric absorption lines, strong emission sky lines, thermal background, science arrays with poorer cosmetics, etc. In order for the DRS to be fully functional for SPIRous first light in 2015, we developed a data simulation tool that incorporates numerous instrumental and observational e_ects. We present an overview of the DRS and the simulation tool architectures.
Monthly Notices of the Royal Astronomical Society | 2018
Pascal Fouqué; Claire Moutou; Lison Malo; Eder Martioli; Olivia Lim; Arvind Rajpurohit; Étienne Artigau; X. Delfosse; Jean-François Donati; Thierry Forveille; J. Morin; Raphaël Delage; René Doyon; E. Hébrard; V. Neves
Present and future high-precision radial-velocity spectrometers dedicated to the discovery of low-mass planets orbiting low-mass dwarfs need to focus on the best selected stars to make an efficient use of telescope time. In the framework of the preparation of the SPIRou Input Catalog, the CoolSnap program aims at screening M dwarfs in the solar neighborhood against binarity, rapid rotation, activity, ... To optimize the selection, the present paper describes the methods used to compute effective temperature, metallicity, projected rotation velocity of a large sample of 440 M dwarfs observed in the visible with the high-resolution spectro-polarimeter ESPaDOnS at CFHT. It also summarizes known and newly-discovered spectroscopic binaries, and stars known to belong to visual multiple systems. A calibration of the projected rotation velocity versus measured line widths for M dwarfs observed by the ESPaDOnS spectro-polarimeter is derived, and the resulting values are compared to equatorial rotation velocities deduced from rotation periods and radii. A comparison of the derived effective temperatures and metallicities with literature values is also conducted. Finally, the radial velocity uncertainty of each star in the sample is estimated, to narrow down the selection of stars to be included into the SPIRou Input Catalogue (SPIC).
arXiv: Instrumentation and Methods for Astrophysics | 2013
X. Delfosse; Jean-François Donati; Driss Kouach; G. Hébrard; René Doyon; Étienne Artigau; F. Bouchy; I. Boisse; A.S. Brun; P. Hennebelle; Thomas Widemann; J. Bouvier; X. Bonfils; J. Morin; Claire Moutou; F. Pepe; S. Udry; J. D. do Nascimento; Silvia H. P. Alencar; B. V. Castilho; Eder Martioli; Shiang-Yu Wang; P. Figueira; N. C. Santos
arXiv: Instrumentation and Methods for Astrophysics | 2015
Claire Moutou; I. Boisse; G. Hébrard; E. Hébrard; Jean-François Donati; X. Delfosse; Driss Kouach
arXiv: Earth and Planetary Astrophysics | 2013
A. Santerne; Jean-François Donati; René Doyon; X. Delfosse; Étienne Artigau; I. Boisse; X. Bonfils; F. Bouchy; G. Hébrard; C. Moutou; S. Udry