▪ 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 …

X-ray emission from stars in the cool half of the Hertzsprung-Russell diagram is generally
attributed to the presence of a magnetic corona that contains plasma at temperatures …

Spin is a fundamental property of all elementary particles. Classically it can be viewed as a
tiny magnetic moment, but a measurement of an electron spin along the direction of an …

Examples of calcium-aluminum–rich inclusions (CAIs) surrounded by thick chondrule
mantles have been found in chondritic meteorites and cast doubt on the conventional belief …

We have developed a Monte Carlo code for the transport of stellar X-rays in an axially
symmetric disk. The code treats Compton scattering and photoelectric absorption and …

The first flare on the Sun was observed exactly 150 years ago. During most of the long
history, only secondary effects have been noticed, so flares remained a riddle. Now the …

The Sun's magnetic activity has steadily declined during its main-sequence life. While the
solar photospheric luminosity was about 30% lower 4.6 Gyr ago when the Sun arrived on …

Solar coronal mass ejections (CMEs) and flares have a statistically well-defined relationship,
with more energetic X-ray flares corresponding to faster and more massive CMEs. How this …

We present a comparison of the gas and dust properties of the dense interstellar matter in
six nearby star-forming regions (pc): ρ Oph, Cha I, R CrA, IC 348, NGC 1333, and Orion. We …

ABSTRACT We observed a 17′× 17′ region of the ρ Oph molecular cloud, using the ACIS-
I array on board the Chandra X-Ray Observatory. A 100 ks exposure observation revealed∼ …