RESUMEN
A detailed overview of the knowledge gaps in our understanding of the heliospheric interaction with the largely unexplored Very Local Interstellar Medium (VLISM) are provided along with predictions of with the scientific discoveries that await. The new measurements required to make progress in this expanding frontier of space physics are discussed and include in-situ plasma and pick-up ion measurements throughout the heliosheath, direct sampling of the VLISM properties such as elemental and isotopic composition, densities, flows, and temperatures of neutral gas, dust and plasma, and remote energetic neutral atom (ENA) and Lyman-alpha (LYA) imaging from vantage points that can uniquely discern the heliospheric shape and bring new information on the interaction with interstellar hydrogen. The implementation of a pragmatic Interstellar Probe mission with a nominal design life to reach 375 Astronomical Units (au) with likely operation out to 550 au are reported as a result of a 4-year NASA funded mission study.
RESUMEN
Large-scale disturbances generated by the Sun's dynamics first propagate through the heliosphere, influence the heliosphere's outer boundaries, and then traverse and modify the very local interstellar medium (VLISM). The existence of shocks in the VLISM was initially suggested by Voyager observations of the 2-3 kHz radio emissions in the heliosphere. A couple of decades later, both Voyagers crossed the definitive edge of our heliosphere and became the first ever spacecraft to sample interstellar space. Since Voyager 1's entrance into the VLISM, it sampled electron plasma oscillation events that indirectly measure the medium's density, increasing as it moves further away from the heliopause. Some of the observed electron oscillation events in the VLISM were associated with the local heliospheric shock waves. The observed VLISM shocks were very different than heliospheric shocks. They were very weak and broad, and the usual dissipation via wave-particle interactions could not explain their structure. Estimates of the dissipation associated with the collisionality show that collisions can determine the VLISM shock structure. According to theory and models, the existence of a bow shock or wave in front of our heliosphere is still an open question as there are no direct observations yet. This paper reviews the outstanding observations recently made by the Voyager 1 and 2 spacecraft, and our current understanding of the properties of shocks/waves in the VLISM. We present some of the most exciting open questions related to the VLISM and shock waves that should be addressed in the future.
RESUMEN
The potential use of different hard and soft parts (otolith, scale, eye lens, dorsal spine, vertebral bone, muscle, and liver) of Rutilus kutum for biomonitoring of 13 major and trace elements (Br, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, S, Sr, and Zn) was evaluated, for the first time. The specimens were sampled from three sampling sites in the Southern Caspian Sea in May 2016. Twenty specimens were collected from each site. The elements' concentrations in the samples were measured by proton-induced X-ray emission (PIXE). In all the hard tissues, except for eye lens, Ca was the most abundant element, whereas Fe was among the least abundant elements. The orders of element occurrence in the two soft tissues were largely similar. Ca, Fe, S, Cl, and K could be detected in all the selected tissues, while Br was detectable only in otolith. Minor similarities among the tissues were identified in the case of eye lens (concerning P, S, and Zn) and liver (in terms of Cl, Fe, and K), whereas, in the case of Sr and Ca, otolith shows the maximum distance. In general, it can be concluded that all the studied hard parts, except for eye lens, may offer alternatives for biomonitoring of Ca, Cl, Fe, K, and S in the southern Caspian Sea. The scales and spines represent a potential non-lethal alternative to the other hard parts.
