Table 1:

Age-sequence of the sources found in Rosette.

	d		M	Young/
Region	[pc]	[103 cm-03]	[]	evolved
7 PL7	35	3.9	2080	3/0
6 PL3	27	1.5	1650	1/3
5 AFGL961	25	9.5	792	4/1
3 Center	20	0.6	22 250	9/4
1+2 Ext. + Mon. Ridge	10	0.6	4280	6/3
4 Shell	10	0.4	11 780	1/2

Notes. The regions are ordered with decreasing distance (d) from the center of NGC 2244 (for simplicity we take as ``center'' the position of cluster B in Fig. 3). The average density ( ) and mass (M) were derived from the column density by determining the area of each region and assuming the same extent of the cloud along the line of sight. The last column gives the number of sources (young vs. evolved).