EVACUATION OF GAS FROM GLOBULAR-CLUSTERS BY WINDS FROM MILLISECOND PULSARS

WHY is so little gas observed within globular clusters? A typical globular cluster contains approximately 10(3) post-turnoff stars, each of which will lose approximately 0.2 M. before its asymptotic giant branch phase of evolution, and approximately 0.1 M. during this phase 1, and so should accumulate 10(2) - 10(3) M. of gas in the 10(8)-year interval between passages of the globular cluster through the galactic disk. (At each disk passage, gas ram pressure will remove the accumulated material 2,3.) But observational searches show that there is scant intracluster gas; in many clusters, there is less than 1M. of gas, orders of magnitude less than theoretical predictions 3. The recent discover 4,5 of multiple millisecond pulsars in globular clusters may resolve this long-standing problem: the relativistic wind from these pulsars is enough to drive gas from stellar mass loss out of the globular cluster.