Search Publications
Secular aberration drift in stellar proper motions. An additional term due to the change in line-of-sight direction
Liu, N.; Zhu, Z.; Liu, J. -C.
Context. The motion of the Solar System barycenter (SSB), the spatial origin of the International Celestial Reference System, causes a directional displacement known as secular aberration. The secular aberration drift caused by the galactocentric acceleration of the SSB has been modeled in the third generation of the International Celestial Refere…
High-precision spectral inversions: Determining what is important for the accurate definition of incident radiation boundary conditions
Heinzel, P.; Gunár, S.
Context. Spectral inversions are used to analyse spectroscopic observations with the aim of deriving the physical properties of the observed plasma, such as the kinetic temperature, density, pressure, degree of ionisation, or macroscopic velocities. One of the key factors ensuring the high precision of the derived plasma properties is having accur…
Solar prominence diagnostics and their associated estimated errors from 1D NLTE Mg II h&k modelling
Barczynski, K.; Schmieder, B.; Labrosse, N. +1 more
Aims: We present further development of the rolling root mean square (rRMS) algorithm. These improvements consist of an increase in computational speed and an estimation of the uncertainty on the recovered diagnostics. This improved algorithm is named the cross root mean square (xRMS) algorithm.
Methods: We used the quantile method to re…
Unveiling the chemical fingerprint of phosphorus-rich stars: II. Heavy-element abundances from UVES/VLT spectra
Masseron, Thomas; García-Hernández, D. A.; Pignatari, Marco +2 more
Context. The atmospheres of phosphorus-rich (P-rich) stars have been shown to contain between 10 and 100 times more P than our Sun. Given its crucial role as an essential element for life, it is especially necessary to uncover the origin of P-rich stars to gain insights into the still unknown nucleosynthetic formation pathways of P in our Galaxy. …
Varying water activity and momentum transfer on comet 67P/Churyumov-Gerasimenko from its non-gravitational forces and torques
Keller, H. U.; Groussin, O.; Attree, N. +9 more
Aims. We investigate the ability of a simultaneous fitting of comet 67P/Churyumov-Gerasimenko's non-gravitational forces, torques, and total water-outgassing rate, as observed by Rosetta, to constrain complex thermophysical models of cometary material. Methods. We extend the previous work of fitting geographically defined surface outgassing models…
Extreme-ultraviolet (EUV) observables of simulated plasmoid-mediated reconnection in the solar corona
Martínez-Sykora, J.; Carlsson, M.; Nóbrega-Siverio, D. +1 more
Context. Understanding the role of magnetic reconnection in the heating and dynamics of the solar atmosphere requires detailed observational data of any observable aspect of the reconnection process, including small-scale features such as plasmoids.
Aims: Here, we examine the capability of active and upcoming instruments to detect plasmoids g…
Non-radial oscillations mimicking a brown dwarf orbiting the cluster giant NGC 4349 No. 127
Reffert, Sabine; Quirrenbach, Andreas; Hunt, Emily L. +2 more
Context. Several evolved stars have been found to exhibit long-period radial velocity variations that cannot be explained by planetary or brown dwarf companions. Non-radial oscillations caused by oscillatory convective modes have been put forth as an alternative explanation, but no modeling attempt has yet been undertaken. Aims. We provide a model…
Activity of main-belt comet 324P/La Sagra
Agarwal, J.; Kim, Y.; Mastropietro, M. +1 more
Aims. We study the activity evolution of the main-belt comet 324P/La Sagra over time and the properties of its emitted dust. Methods. We performed aperture photometry on images taken by a wide range of telescopes at optical and thermal infrared wavelengths between 2010 and 2021. We derived the combined scattering cross section of the nucleus and d…
The impact of improved estimates of radio star astrometric models on the alignment of the Gaia bright reference frame to ICRF3
Lestrade, Jean-François; Xu, Ming H.; Anderson, James M. +12 more
Aims. We investigated the residual orientation offset and spin between the bright (G ≤ 13 mag) frame of the Gaia Early Data Release 3 (Gaia EDR3) and the third realization of the International Celestial Reference Frame (ICRF3). For this purpose, six rotation parameters (orientation offset and its time derivative, the spin), as well as corrections …
Molecular line polarisation from the circumstellar envelopes of asymptotic giant branch stars
Velilla-Prieto, L.; Vlemmings, W. H. T.; Lankhaar, B.
Context. Polarisation observations of masers in the circumstellar envelopes (CSEs) around asymptotic giant branch (AGB) stars have revealed strong magnetic fields. However, masers probe only specific lines of sight through the CSE. Non-masing molecular line polarisation observations can more directly reveal the large-scale magnetic field morpholog…