REM@MIT-MC@sri-unix (11/17/82)
From: Robert Elton Maas <REM at MIT-MC> Apparently just about all yellow-dwarf stars like the Sun have low angular momentum whereas blue-giant stars (the kind that burn themselves out in just a few million years then go supernova and turn into neutron stars or black holes) spin rapidly as predicted from the nebular hypothesis (whorlpool of gas&dust condenses to form star and planets at same time, with central portions spinning fastest because everything is at orbital velocity). The question has arisen why class K stars (yellow dwarfs) have lost the angular momentum they should have had originaly. Observations lately have shown that most of them have strong stellar winds, whereas class B and A stars (blue giants) don't. A theory is that these winds take angular momentum away from the star. Here's a quote from the current (November) Sky&Telescope, page 438: "Probably some physical mechanism common to all these stars, such as strong winds of ionized particles interacting with interstellar magnetic fields, has slowed the solar-type stars but not the hotter B- and A-type stars." Unless for some reason type B and A stars don't have planets, or in their short lifetime they haven't had time to slow down by tidal action of the planets, it looks like wind (ejection of particles) beats out planetary-tidal drag as an explanation, but this question isn't yet really answered for sure.