A type of extremely luminous, eruptive variable that ejects shells of material; abbr. SDOR. These stars include some of the most massive (over 30 solar masses) and most luminous (about 106 solar luminosities) stars. Their spectra are Bpeq–Fpeq; the variability is generally irregular on a timescale of tens of years or even centuries, with amplitudes up to 10 magnitudes. Eta Carinae is a famous example. Alternative names are Hubble–Sandage variable, and luminous blue variable. The older term P Cygni star is now reserved for any star with spectral lines having a P Cygni line profile, indicative of emission from an expanding shell.
Subjects: Astronomy and Astrophysics.