Twilight Blasphemer

The Twilight Blashpemer is an RV Tauri type variable star in the Bacterian Home Galaxy with a double period of 112.448 days. The object is also known as MACHO* 04:55:43.2-67:51:10 in some star charts.

Spectral analysis

Spectrograms obtained of this star show strong C2 bands with a pronounced phase dependence, their strength being greatest at minimum light. The overall spectrum of MACHO*04:55:43.2-67:51:10 is similar to those observed in proto-planetary nebulae.

This unusual star therefore combines the main spectral anomaly of the proto-planetary nebulae with RV Tauri-like photometric variability. No Galactic RV Tauri star is known to have C2 bands as strong as those in MACHO*04:55:43.2-67:51:10.

The occurrence of a luminous, carbon-rich RV Tauri-like star may be explained by assuming that it is a star of 1-2 astronomical masses that has evolved through the M-S-C transition on the extended asymptotic giant branch (AGB) and is now moving to the blue in the pre-planetary nebula stage. This star may therefore represent a link between these two types of star and strengthen the post-AGB interpretation of RV Tauri stars.