The continuous spectra of the substars with surrounding protoplanetary disks were calculated. The results reveal that protoplanetary disc average temperature decreases to 3 K during the period of 5 Myr for substars with masses 0.01M_{Sun} and during the period of 160 Myr for substars with masses 0.08M_{Sun}. Estimations of protoplanetary discs flux maximum depending on the substar mass at the age of 1 Myr are: 4.6 kJy (for 0.01M_{Sun}) and 3.4 MJy (for 0.08M_{Sun}). Maximum of protoplanetary disc radiation before it reaches the temperature of the cosmic microwave background changes within the ranges: from 0.07 mm to 0.58 mm (for substar mass 0.01M_{Sun}) and from 0.02 mm to 0.29 mm (for substar mass 0.08M_{Sun}).

Published in Proceedings of the 14th Young Scientists Conference on Astronomy and Space Physics, Kyiv, Ukraine, April 23-28, 2007