Present
classification: Suggested:
X, XB, XF,
XI, XJ, XND, AM (move to cataclysmics), X, XN, XNB (approximately corresponds to
XNG, a B star
orbiting a compact object),
Xlm (low mass), Xhm (high mass), Xmq (microquasars). In this
class, advice
from experts is especially needed