Five years after its discovery, V838 Monocerotis is still a controversial topic.
NASA classes it as a “Nova-like variable star” rather than a plain nova, because it’s been doing some odd things. A month after it “went off” it suddenly grew 30 times brighter in a single day, for example.
It’s been a season for interesting novae. Astronomers were coasting with the idea that supernoae could be classed into “standard candles” until they discovered a Type 1a supernova forming from too large a star, & Type 2s which could flip across to Type 1.
Now, I guess they’re learning something, because their discussions are laden with exploratory speculations rather than certainty.