F. O. Clark

Pyrolysis of ethylamine. II. Synthesis and microwave spectrum of ethylidenimine (CH3CH=NH)

Microwave rotational spectra assignable to gas phase cis‐ and trans‐ethylidenimine (CH3CH=NH) have been detected in the pyrolysis decomposition products from several alkylamines and from the ring trimer, (CH3CHNH)3. Stark effects, hyperfine and internal rotation splittings have aided the assignment of the observed spectra and allowed the determination of rotational distortion constants, 14N nuclear electric quadrupole coupling constants, internal rotation barriers, and electric dipole moments. Limited structural information was also obtained.

Indication of Outflows from Young Stars in the Serpens Molecular Cloud

The extended infrared emission in the Serpens molecular cloud is associated with three B stars, HD 170634, 170739 and 170784. The dust heating is due to a central stellar and an external interstellar radiation field. The Serpens extended emission exhibits apparent small-scale cavities immediately around the three stars. With the assumption that the cavities have been excavated by stellar winds, mass loss ratesfor these stars may be estimated within the range of 10-13 – 10-11 M⊙ yr-1. The IR emission from the core of the cloud has a double-peaked morphology, the grains is mainly heated by ultraviolet photons produced by shock waves.

Infrared Emission from Outflows Associated with Young Stars

The extended infrared emission detected near many young stars can be used to divine the luminosity, apparent color temperature, and thermal emitting mass of the surrounding regions. The dominant dust heating mechanism appears to be ultraviolet radiation, either from stellar wind shocks or directly from hotter stars. The infrared luminosities from stellar winds of low mass stars are an appreciable fraction of the luminosities of the driving star, and the mechanical luminosity in the winds must be even higher.

IRAS Observations of a ‘Typical’ Dark Cloud

We discuss the implications of the IRAS observations of a regular isolated diffuse cloud. The dependence of infrared radiation on the optical depth is different at short wavelengths (12 and 25 μm) and in the far-IR (60 and 100 μrn). Radiation at both 12 and 25 μrn appears to be due to nonequilibrium emission from the same population of small particles. The far-IR radiation can be explained by steady-state thermal emission from interstellar grains.