R Coronae Borealis variable | F star, G star | | | greater than 1000 Kelvin | supergiant | determined from proper motion and radial velocity | which depends on luminosity class | 0.2 magnitudes or greater | | | from the point of view of Earth's orbit | | some difficulty in distinguishing between various kinds | from the point of view of Earth | or center of gravity | | which is diffused out from the hotter core | CV | | | R Corona Borealis | | | | 8 magnitudes | gravitational contraction and or fusion | which takes place primarily within the core | star catalog | | | cataclysmic variable | | | weak | | | | hydrogen, helium | greater than 0.08 the sun's mass | - R, S, T, U, V, W, X, Y, or Z and the genitive of the latin constellation name
- RR, RS, RT, RU, RV, RW, RX, RY, or RZ and the genitive of the latin constellation name when the single letter designations are exhausted
- AA...AZ, BB...BZ, etc. (omitting J), which ends with QQ...QZ and the genitive of the latin constellation namewhen the RR...RZ designations are exhausted
- V 335, V 336, etc., when the double letter designations are exhausted
| within a period of decades | explosive variable | A very luminous helium-rich, carbon-rich, hydrogen-poor eruptive variable supergiant whose light declines up to 8 magnitudes at irregular intervals. | I |