We present a 3d code for the dynamical evolution of a multi-phase interstellar medium (ISM) coupled to stars via star formation (SF) and feedback processes. The multi-phase ISM consists of clouds (sticky particles) and diffuse gas (SPH): exchange of matter, energy and momentum is achieved by drag (due to ram pressure) and condensation or evaporation processes. The cycle of matter is completed b...

Positrons are known to be produced in interactions between cosmic-ray nuclei and interstellar matter (“secondary production”). Positrons may, however, also be created by dark matter particle annihilations in the galactic halo or in the magnetospheres of near-by pulsars. The nature of dark matter is one of the most prominent open questions in science today. An observation of positrons from pulsa...

Interstellar material surrounding an extrasolar planetary system interacts with the stellar wind to form the stellar astrosphere, and regulates the properties of the interplanetary medium and cosmic ray fluxes throughout the system. Advanced life and civilization developed on Earth during the time interval when the Sun was immersed in the vacuum of the Local Bubble and the heliosphere was large...

Interstellar material surrounding an extrasolar planetary system interacts with the stellar wind to form the stellar astrosphere, and regulates the properties of the interplanetary medium and cosmic ray fluxes throughout the system. Advanced life and civilization developed on Earth during the time interval when the Sun was immersed in the vacuum of the Local Bubble and the heliosphere was large...

We have observed emission from the 492 GHz lines of C I toward six positions in the Ophiuchus molecular cloud complex for which accurate visual extinctions are available. We find that the column density of C I increases with Av to greater than 2 x 1017 em 2 at 100 mag, the column-averaged fractional abundance reaches a peak of about 2.2 x 10-s for Av in the range 4-11 mag and the column-average...

3. Presenters:Nami Sakai, Assistant Professor, Department of Physics, Graduate School of Science, The University of Tokyo Satoshi Yamamoto, Professor, Department of Physics, Graduate School of Science, The University of Tokyo 4. Key Points Background: A new star and its planetary system are formed through gravitational collapse of interstellar gas and dust. It has so far been believed that inte...

We have developed new models of the chemistry of deuterium for investigating fractionation in interstellar molecular clouds. We have incorporated the latest information on reactions which affect deuteration, extended previous models to include S-D bonds for the first time and included the gasphase chemistry of some doubly-deuterated species.We present models for a wide range of physical paramet...