High-speed photometry of, and speculations on, the central star of M 1-2

Photometric observations of the planetary nebula Minkowski 1-2, the central star of which is believed to be an eclipsing binary, are presented. High-speed photometry with a time resolution of 5 sec was obtained for 10 hours over a two-night period with the No. 2 0.9-m reflector at Kitt Peak National Observatory in the standard B filter. Results show no eclipses or other evidence of variability although it was observed continuously for time periods longer than the 4.0002-hour period proposed by Drummond (1980). The findings support the view that the central star of M 1-2 must be either a wide binary or a very unusual single star. A wide-binary model of the system is then suggested which consists of a hot subdwarf and a G-type giant with peculiar abundances surrounded by nebular debris, possibly representing the stage immediately following large-scale mass transfer in the formation of a barium star.