The EC 14026 stars - VII. PG 1605 + 072, a star with many pulsation modes

We report the discovery of large-amplitude (∼0.25 mag) pulsations in the bright (V=12.8) sdB star, PG 1605+072. The dominant period is 480 s, but more than 20 periods were present on at least three separate occasions. Frequency analysis of the complete data set yields more than 30 periods. A few of these are harmonics or linear combinations of the strongest modes. Excluding the latter, the periods span a range of almost 400 s, which contrasts with the typical range