STAR-FORMATION HISTORY IN SHAPLEY-CONSTELLATION-III

The observational stellar age is multiple in Shapley constellation III (SCIII) of the Large Magellanic Cloud (LMC). Previously, the stochast ic self-propagating star formation (SSPSF) model was favored to explai n the age spread in SCIII since it was reported that there was a corre lation between age of stars and distance from the center of the supers hell. Unfortunately, such st. star formation history due to SSPSF is n ot confirmed by any subsequent observations. We find only the multiple age of stars in SCIII. In this paper, we present a first attempt to d escribe multiple star formation history in the context of SSPSF. As a result, we find this criterion: only when the cooling time of coronal gas is longer than the propagation timescale of star formation is SSPS F possible. The strictest conclusion is that if the cooling time is sh orter than the propagation timescale, we must abandon the SSPSF model to explain the star formation history in SCIII. Checking these two tim escales, we find similar to 10(6) yr for the propagation timescale and similar to 10(8) yr for the cooling timescale. Thus, there are plenty of chances to describe the star formation history in SCIII in the con text of a modified SSPSF.