Listed are all scientific papers resulting from an ISSI activity written or co-authored by ISSI Team members, Working Group members, Workshop participants, visitors or staff members.
The emission of volatiles from the surface and subsurface of planetary bodies can provide fundamental knowledge concerning their formation, evolution, and structure. There are a variety of physical processes that shape the structural, kinematic and thermal behavior of the released material.
We present the first numerical simulations of a thin accretion disk around a Reissner–Nordström (RN) naked singularity (NkS; a charged point mass). The gravity of the RN NkS is modeled with a pseudo-Newtonian potential that reproduces exactly the radial dependence of the RN Keplerian orbital frequency; in particular, orbital angular velocity vanishes at the zero gravity radius and has a maximum at 4/3 of that radius.
The ALMACAL–22 survey includes over 2700 h of observations of ALMA phase and amplitude calibrators, spanning frequencies from 84 to 950 GHz across bands 3 to 10. In total, 687 out of the 1047 calibrators have redshifts confirmed with spectroscopy and we find an additional 50 featureless blazars. The redshift distribution of the ALMACAL-22 sample peaks at $z approx 1$ and spans a wide range, from the nuclei of nearby galaxies at $z ll 0.01$ to quasars at $z = 3.742$.
Context. Magnetic switchbacks are large-amplitude magnetic field deflections of Alfvénic nature that are characterized by a high degree of correlation between the velocity and the magnetic field that are routinely detected in the inner heliosphere. Their timescales vary between hundreds of seconds to up to few hours, so that their role within the turbulent transfer of energy from large to small scales in the solar wind is a key question. Aims.
Solar wind forecasting plays a crucial role in space weather prediction, yet significant uncertainties persist duet to incomplete magnetic field observations of the Sun. Isolating the solar wind forecasting errors due to these effects is difficult. This study investigates the uncertainties in solar wind models arising from these limitations.
Plasma-β is an important fundamental physical quantity in solar plasma physics, which determines the dominating process in the solar atmosphere, i.e., magnetic or thermodynamic processes. Here, for the first time, we provide variations of magnetic field and plasma-β along magnetically structured loops from the photosphere to the corona.
Context. In solar-like oscillators, acoustic waves are excited by turbulent motion in the convective envelope and propagate inward, generating a variety of standing pressure modes (p modes). When combining the power of several solar acoustic modes, some studies have reported an excess that is not compatible with pure stochastic excitation. This excess could be a signature of a second mode excitation source. Aims.
Context. Providing a detailed picture of the Sagittarius stream offers important constraints on the build-up of the Galactic halo as well as its gravitational potential at large radii. While several attempts have been made to model the structure of the Sagittarius stream, no model has yet been able to match all the features observed for the stream.
Context. Large-amplitude inversions of the solar wind’s interplanetary magnetic field have long been documented; however, observations from the Parker Solar Probe (PSP) mission have renewed interest in this phenomenon as such features, often termed switchbacks, may constrain both the sources of the solar wind as well as in situ nonlinear dynamics and turbulent heating. Aims.
We present the first X-ray polarization measurements of GX 339–4. IXPE observed this source twice during its 2023–2024 outburst, once in the soft-intermediate state and again during a soft state. The observation taken during the intermediate state shows a significant (4σ) polarization degree PX = 1.3% ± 0.3% and polarization angle θX = −74° ± 7° only in the 3–8 keV band.
