Search Publications
Eruption and propagation of twisted flux ropes from the base of the solar corona to 1 au
Auchère, F.; Janvier, M.; Lugaz, N. +3 more
Context. Interplanetary coronal mass ejections (ICMEs) originate from the eruption of complex magnetic structures occurring in our star's atmosphere. Determining the general properties of ICMEs and the physical processes at the heart of their interactions with the solar wind is a hard task, in particular using only unidimensional in situ profiles.…
Constraining the X-ray reflection in low accretion-rate active galactic nuclei using XMM-Newton, NuSTAR, and Swift
Malizia, A.; Arévalo, P.; Diaz, Y. +8 more
Context. An interesting feature of active galactic nuclei (AGN) accreting at low rates is the weakness of the reflection features in their X-ray spectra, which may result from the gradual disappearance of the torus with decreasing accretion rates. It has been suggested that low-luminosity AGN (LLAGN) would exhibit a different reflector configurati…
Ultra-high-resolution observations of plasmoid-mediated magnetic reconnection in the deep solar atmosphere
de la Cruz Rodríguez, Jaime; van Noort, Michiel; Rouppe van der Voort, Luc H. M.
Context. Magnetic reconnection in the deep solar atmosphere can give rise to enhanced emission in the Balmer hydrogen lines, a phenomenon referred to as Ellerman bombs.
Aims: To effectively trace magnetic reconnection below the canopy of chromospheric fibrils, we analyzed unique spectroscopic observations of Ellerman bombs in the Hα line.
Updated characterization of long-period single companion by combining radial velocity, relative astrometry, and absolute astrometry
Kiefer, F.; Lagrange, A. -M.; Rubini, P. +2 more
Context. Thanks to more than 20 yr of monitoring, the radial velocity (RV) method has detected long-period companions (P > 10 yr) around several dozens of stars. Yet, the true nature of these companions remains unclear because of the uncertainty as to the inclination of the companion orbital plane.
Aims: We wish to constrain the orbital in…
The first two-dimensional stellar structure and evolution models of rotating stars. Calibration to β Cephei pulsator HD 192575
Rieutord, M.; Espinosa Lara, F.; Mombarg, J. S. G.
Contact. Rotation is a key ingredient in the theory of stellar structure and evolution. Until now, stellar evolution codes operate in a one-dimensional framework for which the validity domain in regards to the rotation rate is not well understood.
Aims: In this Letter, we present the first results of self-consistent stellar models in two spat…
Analysing the SEDs of protoplanetary disks with machine learning
Pinte, C.; Woitke, P.; Kamp, I. +2 more
Context. The analysis of spectral energy distributions (SEDs) of protoplanetary disks to determine their physical properties is known to be highly degenerate. Hence, a full Bayesian analysis is required to obtain parameter uncertainties and degeneracies. The main challenge here is computational speed, as one proper full radiative transfer model re…
ED-2: A cold but not so narrow stellar stream crossing the solar neighbourhood
Helmi, A.; Balbinot, E.; Ruiz-Lara, T. +3 more
Context. ED-2 is a stellar stream identified as a compact group in integrals-of-motion space in a local sample of halo stars from the third Gaia data release.
Aims: We investigate its nature and possible association with known halo substructures.
Methods: We explored the current properties of ED-2 members in phase-space and also analysed…
The Araucaria project: High-precision orbital parallaxes and masses of binary stars. I. VLTI/GRAVITY observations of ten double-lined spectroscopic binaries
Kervella, P.; Mérand, A.; Gallenne, A. +4 more
Aims: We aim to measure very precise and accurate model-independent masses and distances of detached binary stars. Precise masses at the < 1% level are necessary to test and calibrate stellar interior and evolution models, while precise and independent orbital parallaxes are essential to check for the next Gaia data releases.
Methods:…
The Gaia-ESO Survey: Chemical evolution of Mg and Al in the Milky Way with machine learning
Gilmore, G.; Bayo, A.; Guiglion, G. +15 more
Context. To take full advantage of upcoming large-scale spectroscopic surveys, it will be necessary to parameterize millions of stellar spectra in an efficient way. Machine learning methods, especially convolutional neural networks (CNNs), will be among the main tools geared at achieving this task.
Aims: We aim to prepare the groundwork for m…
Extending the extinction law in 30 Doradus to the infrared with JWST
Fahrion, Katja; De Marchi, Guido
We measured the extinction law in the 30 Dor star formation region in the Large Magellanic Cloud using Early Release Observations (EROs) taken with Near-Infrared Camera (NIRCam) on board the JWST, thereby extending previous studies carried out with the Hubble Space Telescope to the infrared. We used red clump stars to derive the direction of the r…