Search Publications
Correlation between the optical veiling and accretion properties. A case study of the classical T Tauri star DK Tau
Natta, A.; Ray, T.; Delvaux, C. +3 more
Context. Classical T Tauri stars (cTTs) accrete from their circumstellar disk. The material falls onto the stellar surface, producing an accretion shock, which generates veiling in a star's spectra. In addition, the shock causes a localized accretion spot at the level of the chromosphere.
Aims: Our goal is to investigate the accretion, partic…
Modeling Solar Orbiter dust detection rates in the inner heliosphere as a Poisson process
Zaslavsky, A.; Mann, I.; Kočiščák, S. +3 more
Context. Solar Orbiter provides dust detection capability in the inner heliosphere, but estimating physical properties of detected dust from the collected data is far from straightforward.
Aims: First, a physical model for dust collection considering a Poisson process is formulated. Second, it is shown that dust on hyperbolic orbits is respon…
Slow solar wind sources. High-resolution observations with a quadrature view
Teriaca, Luca; Long, David M.; Schühle, Udo +16 more
Context. The origin of the slow solar wind is still an open issue. One possibility that has been suggested is that upflows at the edge of an active region can contribute to the slow solar wind.
Aims: We aim to explain how the plasma upflows are generated, which mechanisms are responsible for them, and what the upflow region topology looks lik…
Revealing the ionising star of evolved planetary nebulae
Werner, K.; Firpo, V.; Weidmann, W. A. +2 more
Context. Planetary nebulae represent a late stage of the evolution of stars of ordinary mass. The nucleus of a planetary nebula, a stellar remnant, is a faint star for which it is usually difficult to gather spectroscopic data. The spectral types of these stars cover a wide range, mainly separated into two large groups, those rich in hydrogen and …
Atomic oxygen abundance toward Sagittarius B2
Wiesemeyer, Helmut; Güsten, Rolf; Seo, Youngmin +4 more
A substantial fraction of oxygen in diffuse clouds is unaccounted for by observations and is postulated to be in an unknown refractory form, referred to as unidentified depleted oxygen (UDO), which, depending on the local gas density, may contribute up to 50% of the total oxygen content. Previous Infrared Space Observatory (ISO) observations sugge…
The intensity ratio variation of the Si IV 1394/1403 Å lines during solar flares. Resonance scattering and opacity effects
Ding, M. D.; Hong, J.; Yu, H. C.
Context. The Si IV lines at 1394 Å and 1403 Å form in the solar atmosphere at a temperature of ∼104.8 K. They are usually considered optically thin, but their opacity can be enhanced during solar flares. Traditionally, the intensity ratio of these lines are used as an indicator of the optical thickness. However, observations have shown …
The magnetic field clock angle departure in the Venusian magnetosheath and its response to IMF rotation
Xu, Qi; Zhang, Tielong; Rong, Zhaojin +4 more
We investigate the characteristics of interplanetary magnetic field (IMF) draping in the Venusian magnetosheath using both Venus Express (VEX) observations and magnetohydrodynamics simulations. The distributions of magnetosheath field clock angle illustrate the nearly symmetric morphology of draped magnetic field with respect to the solar wind ele…
Cometary dust collected by MIDAS on board Rosetta. I. Dust particle catalog and statistics
Bentley, M. S.; Mannel, T.; Longobardo, A. +5 more
Context. The Micro-Imaging Dust Analysis System (MIDAS) atomic force microscope (AFM) on board the Rosetta comet orbiter has been dedicated to the collection and 3D topographical investigation of cometary dust in the size range of a few hundreds of nanometers to tens of micrometers with a resolution down to a few nanometers.
Aims: We aim to c…
Multi-spacecraft observations of near-relativistic electron events at different radial distances
Rodríguez-Pacheco, J.; Wimmer-Schweingruber, R. F.; Gómez-Herrero, R. +11 more
Aims: We study the radial evolution of near-relativistic solar energetic electron (SEE) events observed by at least two spacecraft at different heliocentric distances and with small separation angles between their magnetic footpoints at the Sun.
Methods: We identified SEE events for which Solar Orbiter and either Wind or STEREO-A had a s…
Temporal and spatial association between microwaves and type III bursts in the upper corona
Reid, H.; Altyntsev, A. T.; Meshalkina, N. S. +2 more
One of the most important tasks in solar physics is the study of particles and energy transfer from the lower corona to the outer layers of the solar atmosphere. The most sensitive methods for detecting fluxes of non-thermal electrons in the solar atmosphere is observing their radio emission using modern large radioheliographs. We analyzed joint o…