HD172468 : New variable star with temporary sudden fading
According to Astron. Astrophys. 364, 706 (2000), Messima et al.
reports that the 7-th mag star HD172468 showed temporary 1-4 mag
fadings, and sometimes undetectable by their APT observations.
T. Kato reported that the object is not (very) hydrogen-deficient,
and looks different from a classical R CrB-type star. The GSC
magnitude 11.16 is more than three magnitudes fainter than usual.
However, Hipparcos didn't pick up this star as a variable star