Related papers: Comparing shocks in planetary nebulae with the sol…
We obtained optical long-slit spectra of four planetary nebulae (PNe) with low-ionization pair of knots, namely He 1-1, IC 2149, KjPn 8 and NGC 7662. These data allow us to derive the physical parameters and excitation of the pairs of…
An analysis of the OIII and SIII temperatures measurements compiled by Perez-Montero et al. of emission line objects consisting of HII galaxies, giant extragalactic HII regions, Galactic HII regions and HII regions from the Magellanic…
Interstellar pickup ions originate from the neutral interstellar medium, are ionized in the heliosphere, and picked up by the solar wind. They initially form a torus-shaped velocity distribution function, which is generally believed to be…
Galactic winds are crucial to the cosmic cycle of matter, transporting material out of the dense regions of galaxies. Observations show the coexistence of different temperature phases in such winds, which is not easy to explain. We present…
A present prevailing open problem planetary nebulae research, and photoionized gaseous nebulae research at large, is the systematic discrepancies in ionic abundances derived from recombination and collisionally excited lines in many H II…
We carry out high resolution two-dimensional radiation-hydrodynamic numerical simulations to study the formation and evolution of hot bubbles inside planetary nebulae (PNe). We take into account the evolution of the stellar parameters, wind…
The $\textit{Parker Solar Probe}$ ($\textit{PSP}$) mission has observed near-continuous power in parallel ion cyclotron waves (PICWs) in the young, fast solar wind. These waves are unlikely to be directly produced by the turbulent cascade…
Hot temperature minerals have been detected in a large number of comets and were also identified in the samples of Comet Wild 2 that were returned by the Stardust mission. Meanwhile, observations of the distribution of hot minerals in young…
Recent high-resolution imaging and spectroscopic observations have generated renewed interest in spicules' role in explaining the hot corona. Some studies suggest that some spicules, often classified as type II, may provide significant mass…
Context. In binary star systems, the winds from the two components impact each other, leading to strong shocks and regions of enhanced density and temperature. Potentially habitable circumbinary planets must continually be exposed to these…
Solar ionizing factors are responsible for modulation of interstellar neutral gas and its derivative populations inside the heliosphere. We provide an overview of the current state of knowledge about them for heliospheric particles inside…
The properties of star cluster winds in the supercritical, catastrophic cooling regime are discussed. We demonstrate that strong radiative cooling may inhibit superwinds and, after a rapid phase of accumulation of the ejected material…
Shock-wave heating within the solar nebula is one of the leading candidates for the source of chondrule-forming events. Here, we examine the possibility of compound chondrule formation via optically thin shock waves. Several features of…
One key feature of the interacting stellar winds model of the formation of planetary nebulae (PNe) is the presence of shock-heated stellar wind confined in the central cavities of PNe. This so-called hot bubble should be detectable in…
We explore the formation of superbubbles through energy deposition by multiple supernovae (SNe) in a uniform medium. We use total energy conserving, 3-D hydrodynamic simulations to study how SNe correlated in space and time create…
This paper explores the thermodynamics of fluctuating polytropic processes and their connection to turbulence. It is shown that random fluctuations of polytropic processes produce a nonzero overall heating of a particle system, e.g., solar…
High-energy particles may be accelerated widely in stellar coronae; probably by the same processes we find in the Sun. Here, we have learned of two physical mechanisms that dominate the acceleration of solar energetic particles (SEPs). The…
Many round or nearly roundish Planetary Nebulae (PNe) show multiple shells and halo structures during their evolutionary stage near the maximum temperature of their central star. Controversial debate is currently ongoing if these structures…
X-rays from planetary nebulae (PNs) are believed to originate from a shock driven into the fast stellar wind (v ~ 1000 km/s) as it collides with an earlier circumstellar slow wind (v ~ 10 km/s). In theory, the shocked fast wind (hot bubble)…
Super Earths and mini Neptunes likely have a wide range of atmospheric compositions, ranging from low-molecular mass atmospheres of H2 to higher molecular atmospheres of water, CO2, N2, or other species. Here, we systematically investigate…