A new pulsating PG 1159 white dwarf : RXJ 2117.1+3412

RXJ 2117.1+3412 is a newly spectroscopically identified bright PG1159 star discovered in the ROSAT XRT sky survey. We report in this Letter the results of rapid photometry observations performed at the 2.5 m Nordic Optical Telescope, on 1992 August 23-27. RXJ 2117.1+3412 is a low amplitude multiperiodic pulsator. The analysis of 28 h of rapid photometry reveals that the light curve contains at least 24 frequencies. The power spectrum is dominated by a 5 mmag amplitude pulsation of 821 s period. Other modes are found in a wide range of periods: 246 s-3150 s