We measure two new times of light maximum of the SX Phoenicis star DY Pegasi in 2008 December and collect 410 pe/CCD times of light maximum that had been published. These data could be modeled with a nonlinear fit including a continuously decreasing period change (dP/dt = 鈥?.04 × 10鈥?2 days day鈥?) and a periodic change with a period of 42.2聽yr. If this periodic change is caused by the light traveling time effect of an orbital motion of DY Pegasi in a binary system, the deduced mass of the companion could be 0.028 M 鈽?/SUB> and it is probably a brown dwarf.
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