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

Vauclair, G.; Belmonte, J. A.; Pfeiffer, B.; Chevreton, M.; Dolez, N.; Motch, C.; Werner, K.; Pakull, M. W.
Referencia bibliográfica

Astronomy and Astrophysics (ISSN 0004-6361), vol. 267, no. 1, p. L35-L38.

Fecha de publicación:
RXJ 2117.1 + 3412 is a newly spectroscopically identified bright PG1159 star discovered in the ROSAT XRT sky survey. We report the results of rapid photometry observations performed at the 2.5m Nordic Optical Telescope, on 1992 August 23-27. RXJ2117.1 + 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 - 3150 s. A test on the period distribution indicates two mean period spacings at 20.48 s and 22.61 s which, when interpreted as the expected period spacings in the asymptotic limit for g-modes of degree l = 1 and l = 2, lead to a mass of 0.62 and 0.58 solar mass, respectively.