Time-resolved CCD photometry of an ensemble of stars in the open cluster M67 Academic Article uri icon


  • Stars in the central region of the old open cluster M67 were monitored for stability using CCD, time-resolved photometry. Five sites with 1 m class telescopes participated in an intensive monitoring effort, yielding contiguous 14 night coverage with 1 min temporal resolution. Noise levels to 0.0008 mag variation relative to an ensemble mean were attained at 13th mag over 9 hr time series. Limits to detection of coherent oscillations with periods of 3-20 min, assuming a solarlike spectrum of frequencies, are 100 mag (30 times solar amplitude) for the best cases. Evidence suggestive of p-mode oscillations is shown for a few stars, but an unambiguous detection is not claimed. Serendipitous detection was made of: two new W UMa stars in M67, two oscillating blue stragglers (with multiple modes), a likely AM Her cataclysmic variable with a 2.091 hr period, and several stars with low-amplitude intensity changes over timescales of 1-10 days, that presumably results from rotation or orbital motion.

published proceedings

  • The Astronomical Journal

author list (cited authors)

  • Gilliland, R. L., Brown, T. M., Duncan, D. K., Suntzeff, N. B., Lockwood, G. W., Thompson, D. T., ... Penprase, B. E.

citation count

  • 94

complete list of authors

  • Gilliland, Ronald L||Brown, Timothy M||Duncan, Douglas K||Suntzeff, Nicholas B||Lockwood, G Wesley||Thompson, Don T||Schild, Rudolph E||Jeffrey, William A||Penprase, Bryan E

publication date

  • February 1991