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.
In situ observations of the solar wind have shown that the electron velocity distribution function (VDF) consists of a quasi-Maxwellian core, comprising most of the electron population, and two sparser components: the halo, which are suprathermal and quasi-isotropic electrons, and an escaping beam population, the strahl.
An overview is presented of our current understanding and open questions related to magnetic reconnection in solar flares and the near-sun (within around 20Rs) solar wind. The solar-flare-related topics include the mechanisms that facilitate fast energy release and that control flare onset, electron energization, ion energization and abundance enhancement, electron and ion transport, and flare-driven heating.
Context. The winds of massive stars remove a significant fraction of their mass, strongly impacting their evolution. As a star evolves, the rate at which it loses mass changes. In stellar evolution codes, different mass-loss recipes are employed for different evolutionary stages. The choice of the recipes is user-dependent and the conditions for switching between them are poorly defined. Aims.
Aims. We investigate the brightening behavior of long-period comets as a function of dynamical age, defined by the original reciprocal semimajor axis, 1/a0. Our goal is to test long-standing claims about comet behavior using a large number of available measurements. Methods. We used a large set of photometric observations to compute and analyze global and local brightening curves for 272 long-period comets.
High energy solar protons were observed by particle detectors aboard spacecraft in near-Earth orbit on May 11, 2024 and produced the 74th ground level enhancement (GLE74) event registered by ground-based neutron monitors. This study involves a detailed reconstruction of the neutron monitor response, along with the identification of the solar eruption responsible for the emission of the primary particles, utilizing both in situ and remote-sensing.
During the March equinox of 2023, a strong easterly wind of ∼80 m s−1 appeared at an altitude of ∼82 km in the equatorial upper mesosphere, which is regarded as an enhancement of the mesopause semi‐annual oscillation. In this study, a new reanalysis data available up to 110 km was used to investigate its momentum budget.
Context. The origin of large-amplitude magnetic field deflections in the solar wind, known as magnetic switchbacks, is still under debate. These structures, which are ubiquitous in the in situ observations made by Parker Solar Probe (PSP), likely have their seed in the lower solar corona, where small-scale energetic events driven by magnetic reconnection could provide conditions ripe for either direct or indirect generation. Aims.
We present a sample of 1956 individual stellar clumps at redshift $0.7lt zlt 10$, detected with JWST/NIRCam in 476 galaxies lensed by the galaxy cluster Abell2744. The lensed clumps present magnifications ranging between $mu$ = 1.8 and $mu$ = 300. We perform simultaneous size-photometry estimates in 20 JWST/NIRCam median and broad-band filters from 0.7 to 5 $mu$m. Spectral energy distribution (SED) fitting analyses enable us to recover the physical properties of the clumps.
One of the most striking manifestations of orderly behavior emerging out of complex interactions in any astrophysical system is the 11 yr cycle of sunspots. However, direct sunspot observations and reconstructions of long-term solar activity clearly exhibit amplitude fluctuations beyond the decadal timescale, which may be termed as supradecadal modulation.
Context. The localised formation of planetesimals can be triggered with the help of streaming instability when the local pebble density is high. This can happen at various locations in the disc, and it leads to the formation of local planetesimal rings. The planetesimals in these rings subsequently grow from mutual collisions and by pebble accretion. Aims.
