Cometary plasma tails are accelerated by the solar wind to ≈ half its velocity, corresponding to some 10/sup2 times the solar-wind momentum density. The authors corroborate Alfvén's (1957) "wind-sock" mechanism according ...

The facts indicating that large line-forming regions occur among the best-studied close binaries are outlined. It is pointed out that emission lines are often redshifted while absorption lines are blueshifted, emission ...