R Carinae
R Carinae is a double star in the southern constellation of Carina. The brighter component is a variable star that can be viewed with the naked eye at peak brightness, but is usually too faint to be seen without a telescope, having an apparent [visual magnitude] that fluctuates around 7.43. This star is located at a distance of approximately 600 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +28 km/s.
Benjamin Apthorp Gould discovered the variable star, in 1871. It appeared with its variable star designation in Annie Jump Cannon's 1907 work, Second Catalogue of Variable Stars. The main component is an aging red giant star on the asymptotic [giant branch] with a stellar classification of M6/7pe. It is classified as a pulsating Mira type variable star and its visual brightness varies with an average amplitude of 4.25 magnitudes over a period of. Its average maximum visual magnitude is, but the brightest observed maximum was magnitude 3.9. The pulsations make its size change, in 2014, it was times larger than the Sun, while in 2020 it was times larger. This star is surrounded by a dusty shell, with properties that are consistent with iron-poor silicates or corundum, extending from around three stellar radii outward.
The companion is a magnitude 11.30 star at an angular separation of along a position angle of 132° from the main star, as of 2015.