Alignment of Circumstellar H-H Flows by the Interstellar Magnetic Field

The magnetic field around late - type stars revealed by the circumstellar H 2 O masers

Through polarization observations, circumstellar masers are excellent probes of the magnetic field in the envelopes of late-type stars. Whereas observations of the polarization of the SiO masers close to the star and on the OH masers much further out were fairly commonplace, observations of the magnetic field strength in the intermediate density and temperature region where the 22 GHz H 2 O mas...

Formation of H 3− by radiative association of H 2 and H− in the interstellar medium

Interstellar H(3)(+).

Protonated molecular hydrogen, H(3)(+), is the simplest polyatomic molecule. It is the most abundantly produced interstellar molecule, next only to H(2), although its steady state concentration is low because of its extremely high chemical reactivity. H(3)(+) is a strong acid (proton donor) and initiates chains of ion-molecule reactions in interstellar space thus leading to formation of complex...

The Spin Temperature of Warm Interstellar H

Collisional excitation of the λ21cm hyperfine transition is not strong enough to thermalize it in warm neutral (" intercloud ") interstellar gas, which we show by simultaneously solving the equations of ionization and collisional equilibrium under typical conditions. Coupling of the λ21cm excitation temperature and local gas motions may be established by the Ly-α radiation field, but only if st...

A new infrared band in Interstellar and Circumstellar Clouds : C 4 or C 4 H ?

We report on the detection with the Infrared Space Observatory (ISO) of a molecular band at 57.5 μm (174 cm) in carbon-rich evolved stars and in Sgr B2. Taking into account the chemistry of these objects the most likelihood carrier is a carbon chain. We tentatively assign the band to the ν5 bending mode of C4 for which a wavenumber of 170-172.4 cm has been derived in matrix experiments (Withey ...