Betelgeuse- BETA DOR (Beta Doradus). Among the most important of all stars are the Cepheid variables, named after the prototype, Delta Cephei. Many of them dot the naked- eye starry sky, their number including Eta Aquilae, Zeta Geminorum (Mekbuda), even Polaris, the brightest of them (though Polaris’s variations are too small to be witnessed by eye). Here is another bright one, fourth magnitude (averaging 3.76) Beta Doradus, the second brightest star (after Alpha) in the modern southern constellation Dorado, the Swordfish.
- Red giant (Wikipedia)
A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses (M☉)) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around 5,000 K (4,700 °C; 8,500 °F) or lower. The appearance of the red giant is from yellow-white to reddish-orange, including the spectral types K and M, sometimes G, but also class S stars and most carbon stars.