Wharemaru Observatory, P. O. Box 173, Awanui, 0451, New Zealand
Received June 28, 2009; revised September 2, 2009; accepted September 2, 2009
Abstract
The period changes of the dual maxima Mira star BH Cru and the
associated color changes are discussed. UBV measures before the change in
period began are compared with those after the star had stabilized at the new,
longer, period and those made during the twelve cycles of lengthening period
are summarized. A 30% increase in mean V brightness is noted, as is a distinctly
redder color in B—V. The apparent single maximum that has now appeared can
be explained by a relative brightening of the second maximum with the first
maximum now somewhat hidden by it.