The interstellar medium of galaxies is the reservoir out of which stars are born and into
which stars inject newly created elements as they age. The physical properties of the …

▪ Abstract Observational studies of low-mass stars during their early stages of evolution, from
protostars through the zero-age main sequence, show highly elevated levels of magnetic …

We have used the Very Long Baseline Array to measure the trigonometric parallax of
several member stars of the Orion Nebula Cluster showing non-thermal radio emission. We …

We present a model for the photoevaporation of circumstellar disks or dense clumps of gas
by an external source of ultraviolet radiation. Our model includes the thermal and dynamic …

▪ Abstract Radio astronomy has provided evidence for the presence of ionized atmospheres
around almost all classes of nondegenerate stars. Magnetically confined coronae dominate …

We use 3D hydrodynamical models to investigate the effects of massive star feedback from
winds and supernovae on inhomogeneous molecular material left over from the formation of …

We report on observations of M42 made with the Hubble Space Telescope (HST)
immediately after the successful repair and refurbishment mission. Images were made in the …

We present observations of the Orion Nebula made with the Hubble Space Telescope in
which a number of stars are seen surrounded by dark silhouettes seen projected against the …

A theoretical parameter study of dense photodissociation regions is presented. It is found
that when the gas density is sufficiently high relative to the FUV flux, self-shielding of the …

T Tauri stars are very young (< 107 y), low mass (< 3Mo) pre-main sequence stars. Although
this class of stars has been defined already more than 40 years ago on the basis of their …