アルファルド

The solitary bright star of Hydra, the Water Snake, Alphard bears the Alpha designation of the largest of the modern constellations. It is an orange K-type star with a decidedly red-leaning colour index of 1.44, consistent with the cooler photospheres of evolved K giants. Alphard shines at apparent magnitude 1.99 and lies approximately 180 light-years away; its absolute magnitude of −1.72 places its true output well above that of Sun-like stars, a luminosity partly veiled by distance. Set within a sprawling but faint region of sky, it stands out largely for its isolation, the lone conspicuous point across a long stretch of the sinuous constellation — a prominence that earned it a traditional name denoting the solitary one.