Everything that became part of the primitive solar nebula first passed through the interstellar medium and the dense molecular cloud from which the nebula collapsed. We begin with a brief discussion of the connection between dense molecular clouds and the formation of solar-type stars. We then review processes that occur in these environments in order to constrain the chemical and physical prop...

ABSTRACT The recent interstellar detection of cyanonaphthalenes brings interest in related aromatic molecular species that could be present similar astronomical environments. In this context, ethynyl derivatives naphthalene are promising candidates to observed the Taurus Molecular Cloud (TMC-1), where together with cyano- and ethynyl-derivatives cyclopentadiene benzene have been detected. To en...

The reactions of ground-state atomic carbon with acetylene, (1), methylacetylene, (2), 22 3 ethylene, (3), and propylene, (4), are investigated at relative collision energies between 8.8 24 36 and 45 kJ mol~1 in crossed-beam experiments to elucidate the reaction products and chemical dynamics of atom-neutral encounters relevant to the formation of carbon-bearing molecules in the interstellar me...

We present a study of the kinetic energy dissipation in interstellar cloud collisions. The main aim is to understand the dependence of the elasticity (defined as the ratio of the final to the initial kinetic energy of the clouds) on the velocity and mass ratio of the colliding clouds, magnetic field strength, and gas metallicity for head-on collisions. The problem has been studied both analytic...

In the early 1990s, after its Jupiter flyby, the Ulysses spacecraft identified interstellar dust in the solar system. Since then the in-situ dust detector on board Ulysses continuously monitored interstellar grains with masses up to 10−13 kg, penetrating deep into the solar system. While Ulysses measured the interstellar dust stream at high ecliptic latitudes between 3 and 5 AU, interstellar im...

Over 130 molecules have been identified in the interstellar gas and circumstellar shells, the largest among them is a carbon chain with 13 atoms and molecular weight of 147 (twice that of the simplest amino acid glycine). The high reliability of astronomical identifications, as well as the fairly accurate quantitative analysis which can often be achieved, is emphasized. Glycine itself has been ...

The interstellar medium is highly dynamic and turbulent. However, little or no attention has been paid in the literature to the implications that this fact has on the validity of at least six common assumptions on the virial theorem (VT), which are as follows. (i) The only role of turbulent motions within a cloud is to provide support against collapse; (ii) the surface terms are negligible comp...

Normal field stars located behind dense clouds are a valuable resource in interstellar astrophysics, as they provide continua in which to study phenomena such as gas-phase and solid-state absorption features, interstellar extinction and polarization. This paper reports the results of a search for highly reddened stars behind the Taurus Dark Cloud complex. We use the Two Micron All Sky Survey (2...

Observational constraints on the theory of the IMF are reviewed. These observations include the new result that star formation is very rapid, usually going from start to finish in only 1 or 2 dynamical times on a wide range of scales. This result, combined with the observation that the IMF is independent of cluster density over a factor of several hundred, implies that protostar coagulation dur...

Aims. We study the LMC interstellar medium in the field of the nebula N157B, which contains a supernova remnant, an OB association, ionized gas, and high-density dusty filaments in close proximity. We investigate the relative importance of shock excitation by the SNR and photo-ionization by the OB stars, as well as possible interactions between the supernova remnant and its environment. Methods...