A5069657828- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Gamma-ray bursts and supernovae
- Pituitary Gland Disorders and Treatments
- Calibration and Measurement Techniques
- Bone and Joint Diseases
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Hematological disorders and diagnostics
- Molecular spectroscopy and chirality
- Hip disorders and treatments
- Space Exploration and Technology
- Scientific Research and Discoveries
- Ionosphere and magnetosphere dynamics
- Solid-state spectroscopy and crystallography
- Advanced Chemical Physics Studies
- Galaxies: Formation, Evolution, Phenomena
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
Université Paris Sciences et Lettres
2024
Centre National de la Recherche Scientifique
2021-2024
Center for Astrophysics Harvard & Smithsonian
2023-2024
Université de Toulouse
2021-2024
Laboratoire Univers et Théories
2024
Université Paris Cité
2024
Janssen (France)
2024
Institut de Recherche en Astrophysique et Planétologie
2022-2023
Université Toulouse III - Paul Sabatier
2023
Aix-Marseille Université
2021
ABSTRACT In this paper, we present an analysis of near-infrared spectropolarimetric and velocimetric data the young M dwarf AU Mic, collected with SPIRou at Canada–France–Hawaii telescope from 2019 to 2022, mostly within Legacy Survey. With these data, study large- small-scale magnetic field detected through unpolarized circularly polarized Zeeman signatures spectral lines. We find that both are modulated stellar rotation period (4.86 d), evolve on a time-scale months under differential...
ABSTRACT We report first results on a method aimed at simultaneously characterizing atmospheric parameters and magnetic properties of M dwarfs from high-resolution near-IR spectra recorded with SPIRou in the framework Legacy Survey (SLS). Our analysis relies fitting synthetic computed marcs model atmospheres to selected spectral lines, both sensitive insensitive fields. introduce new code, ZeeTurbo, obtained by including Zeeman effect polarized radiative transfer capabilities Turbospectrum....
Context. The rotation period of stars is an important parameter along with mass, radius, effective temperature. It essential for any radial velocity monitoring, as stellar activity can mimic the presence a planet at period. Several methods exist to measure it, including long sequences photometric measurements or temporal series indicators. Aims. Here, we use circular polarization in near-infrared spectral lines sample 43 quiet M dwarfs and compare measured periods those obtained other...
We present near-infrared spectropolarimetric observations of a sample 43 weakly- to moderately-active M dwarfs, carried with SPIRou at the Canada-France-Hawaii Telescope in framework Legacy Survey from early 2019 mid 2022. use 6700 circularly polarised spectra collected for this investigate longitudinal magnetic field and its temporal variations all stars, which we diagnose, through quasi-periodic Gaussian process regression, periodic modulation longer-term fluctuations field. detect...
We report the detection and characterization of transiting sub-Neptune TOI-1759 b, using photometric time series from Transiting Exoplanet Survey Satellite (TESS) near-infrared spectropolarimetric data Spectro-Polarimètre Infra Rouge (SPIRou) on Canada-France-Hawaii Telescope. b orbits a moderately active M0V star with an orbital period 18.849975 ± 0.000006 days, we measured planetary radius mass 3.06 0.22 R ⊕ 6.8 2.0 M . Radial velocities were extracted SPIRou spectra both cross-correlation...
ABSTRACT We report new observations of the classical T Tauri star CI Tau with SPIRou near-infrared spectropolarimeter and velocimeter at Canada–France–Hawaii Telescope (CFHT) in late 2019, 2020, 2022, complemented obtained ESPaDOnS optical CFHT 2020. From our spectra, to which we applied least-squares deconvolution, infer longitudinal fields clearly modulated 9-d rotation period Tau. Using Zeeman–Doppler imaging, reconstruct large-scale magnetic topology, first from data only all three...
Abstract Determination of fundamental parameters stars impacts all fields astrophysics, from galaxy evolution to constraining the internal structure exoplanets. This paper presents a detailed spectroscopic analysis Barnard’s star (otherwise known as Gl 699) that compares an exceptionally high-quality (an average signal-to-noise ratio ∼1000 in entire domain), high-resolution near-infrared (NIR) spectrum taken with Canada-France-Hawaii Telescope/SPIRou PHOENIX-ACES stellar atmosphere models....
We describe advances on a method designed to derive accurate parameters of M dwarfs. Our analysis consists in comparing high-resolution infrared spectra acquired with the near-infrared spectro-polarimeter SPIRou synthetic computed from MARCS model atmospheres, order effective temperature ($T_{\rm eff}$), surface gravity ($\rm \log{g}$), metallicity ([M/H]) and alpha-enhancement [\alpha/Fe]$) 44 dwarfs monitored within Legacy Survey (SLS). Relying 12 these stars, we calibrated our by refining...
ABSTRACT We present the results of an analysis aimed at probing small-scale magnetic fields M dwarfs observed with SPIRou, nIR high-resolution spectro-polarimeter installed Canada–France–Hawaii Telescope, in context SPIRou Legacy Survey. Our relies on median spectra built from several tens recorded between 2019 and 2022, synthetic computed ZeeTurbo code for various combination atmospheric parameters field strengths. pursue efforts undertaken a previous study focus 44 weakly to moderately...
A major endeavor of this decade is the direct characterization young giant exoplanets at high spectral resolution to determine composition their atmosphere and infer formation processes evolution. Such a goal represents challenge owing small angular separation luminosity contrast with respect parent stars. Instead designing implementing completely new facilities, it has been proposed leverage capabilities existing instruments that offer either high-contrast imaging or high-dispersion...
The stellar activity of M dwarfs is the main limitation for discovering and characterizing exoplanets orbiting them since it induces quasi-periodic RV variations. We aim to characterize magnetic field early, moderately active, dwarf Gl205 in optical nIR domains. obtained high-precision quasi-simultaneous spectra with SOPHIE spectrograph SPIRou spectropolarimeter between 2019 2022. computed RVs from both instruments Stokes V profiles. used ZDI map large-scale over time span observations....
We report results of a spectropolarimetric monitoring the young Sun-like star V1298~Tau based on data collected with near-infrared spectropolarimeter SPIRou at Canada-France-Hawaii Telescope between late 2019 and early 2023. Using Zeeman-Doppler Imaging Time-dependent Magnetic Stars methods circularly polarized spectra, we reconstructed large-scale magnetic topology (and its temporal evolution), found to be mainly poloidal axisymmetric an average strength varying from 90 170 G over ~3.5...
We present the results of a study aiming at retrieving fundamental parameters M dwarfs from spectra secured with SPIRou, near-infrared high-resolution spectropolarimeter installed Canada-France-Hawaii Telescope (CFHT), in framework SPIRou Legacy Survey (SLS). Our relies on comparing observed two grids synthetic spectra, respectively computed PHOENIX and MARCS model atmospheres, ultimate goal optimizing precision which can be determined. In this first step, we applied our technique to 12...
Context . Recent advances in the development of precise radial velocity (RV) instruments near-infrared (near-IR) domain, such as SPIRou, have facilitated study M-type stars to more effectively characterize planetary systems. However, near-IR presents unique challenges exoplanet detection due various sources planet-independent signals which can result systematic errors RV data. Aims In order address posed by exoplanetary systems around using observations, we introduced a new data-driven...
Context. The galactic winds of starburst galaxies (SBGs) give rise to remarkable structures on kiloparsec scales. However, the evolution and shape these giant wind bubbles, as well properties shocks they develop, are not yet fully understood. Aims. We aim understand what shapes SBGs, with a particular focus role large-scale magnetic fields in dynamical wind-inflated bubbles. In addition, we explore where conditions for efficient particle acceleration met systems. Methods. performed...
ABSTRACT In this paper, we report near-infrared observations of the classical T Tauri star TW Hya with SPIRou high-resolution spectropolarimeter and velocimeter at 3.6-m Canada–France–Hawaii Telescope in 2019, 2020, 2021, 2022. By applying Least-Squares Deconvolution (LSD) to our circularly polarized spectra, derived longitudinal fields that vary from year –200 +100 G, exhibit low-level modulation on 3.6 d rotation period Hya, despite being viewed almost pole-on. We then used Zeeman–Doppler...
Glucocorticoid excess is one of the most important causes bone disorders. Bone marrow fat (BMF) has been identified as a l new mediator metabolism. Cushing syndrome (CS), main regulator adipose tissue distribution but its impact on BMF unknown. The objective study was to evaluate effect chronic hypercortisolism BMF.This cross-sectional study. Seventeen active and seventeen cured ACTH-dependent CS patients along with controls (matched group for age sex) were included.the content femoral neck...
In this paper we report near-infrared observations of the classical T Tauri star TW Hya with SPIRou high-resolution spectropolarimeter and velocimeter at 3.6-m Canada-France-Hawaii Telescope in 2019, 2020, 2021 2022. By applying Least-Squares Deconvolution (LSD) to our circularly polarized spectra, derived longitudinal fields that vary from year -200 +100 G, exhibit low-level modulation on 3.6 d rotation period Hya, despite being viewed almost pole-on. We then used Zeeman-Doppler Imaging...
Context . Supernovae remnants (SNRs) represent a major source of feedback from stars on the interstellar medium galaxies. During latest stage supernova explosions (which lasts 10–100 kyr), shock waves produced by initial blast modify chemistry gas and dust, inject kinetic energy in surroundings, may alter star formation characteristics. Simultaneously, γ -ray emission is generated interaction between ambient cosmic rays, particular those locally accelerated early stages explosion. Aims We...
ABSTRACT We present in this paper an analysis of near-infrared observations the 0.3-${\rm M}_{\odot }$ protostar V347 Aurigae (V347 Aur) collected with SPIRou high-resolution spectropolarimeter and velocimeter at 3.6-m Canada-France-Hawaii Telescope from 2019 October to 2023 April. From a set 79 unpolarized circularly polarized spectra Aur which we applied Least-Squares Deconvolution (LSD), derived radial velocities longitudinal fields, along their temporal variations over our monitoring...
Studies of atmospheres directly imaged extrasolar planets with high-resolution spectrographs have shown that their characterization is predominantly limited by noise on the stellar halo at location studied exoplanet. An instrumental combination high-contrast imaging and high spectral resolution suppresses this resolves lines can therefore yield higher quality spectra. We study performance proposed HiRISE fiber coupling between direct imager SPHERE spectrograph CRIRES+ Very Large Telescope...
TOI-1695 is a V-mag=13 M-dwarf star from the northern hemisphere at 45$\,$pc Sun, around which 3.134-day periodic transit signal super-Earth candidate was identified in TESS photometry. With depth of 1.3$\,$mmag, radius TOI-1695.01 estimated by pipeline to be 1.82$\,$R$_\oplus$ with an equilibrium temperature $\sim 620\,$K. We successfully detect reflex motion and establish it due planetary companion orbital period consistent photometric thanks year-long radial-velocity monitoring SPIRou...
We report results of a spectropolarimetric monitoring the young Sun-like star V1298~Tau based on data collected with near-infrared spectropolarimeter SPIRou at Canada-France-Hawaii Telescope between late 2019 and early 2023. Using Zeeman-Doppler Imaging Time-dependent Magnetic Stars methods circularly polarized spectra, we reconstructed large-scale magnetic topology (and its temporal evolution), found to be mainly poloidal axisymmetric an average strength varying from 90 170 G over ~3.5...
Abundance matching between galaxies and halos has proven to be an informative technique, less dependent on detailed physical approximations than some other methods. We extend the discussion dwarf realm study of alternative hypothesis that dark matter is composed ultra--light particles: Fuzzy Dark Matter. find that, given current observations, both CDM FDM have difficulties with systems in local group, but if mechanisms are proposed alleviate these difficulties, they make radically different...
The stellar activity of M dwarfs is the main limitation for discovering and characterizing exoplanets orbiting them since it induces quasi-periodic RV variations. We aim to characterize magnetic field early, moderately active, dwarf Gl205 in optical nIR domains. obtained high-precision quasi-simultaneous spectra with SOPHIE spectrograph SPIRou spectropolarimeter between 2019 2022. computed RVs from both instruments Stokes V profiles. used ZDI map large-scale over time span observations....