TX Cam is a long-period Mira variable with highly variable amplitude. It's also a known bright IR source and has strong maser emission, both of which come from the mass that's being shed by this rapidly evolving star. The long-period Miras are interesting objects because they're probably representative of the higher-mass AGB stars, those between 3 and 9 solar masses. It's also likely that these stars are losing mass at the highest rates, and we might be looking at stars getting ready to form planetary nebulae within the next several thousand years.
The long-period stars with periods longer than 550 days or so aren't universally well observed by the AAVSO and other VSOs around the world, although there are a few that are -- like S Cas for example.