Robuta

https://www.aanda.org/articles/aa/ref/2002/16/aa2092/aa2092.html S Orionis: A Mira-type variable with a marked period decrease | Astronomy & Astrophysics (A&A) s orionis a type variable https://www.aanda.org/articles/aa/abs/2002/16/aa2092/aa2092.html S Orionis: A Mira-type variable with a marked period decrease | Astronomy & Astrophysics (A&A) s orionis a type variable