RA 109.6770° · Dec -24.9544° · star
25 more points to reach Mythic.
30Tau CMa is an anomaly variable star. It lies about 2,992.3 light-years from Earth, sits in the constellation CMa, shines at apparent magnitude 4.37 and has spectral type O9Ib.
Its spectrum reads O9Ib — an O-type star — the hottest, rarest main class there is. Fewer than one star in a million is an O, and none of them lasts long.
Look for 30Tau CMa in the constellation CMa. At apparent magnitude 4.37, it can be glimpsed with the unaided eye under dark skies.
Like any astronomical target, 30Tau CMa is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.
30Tau CMa scores 95 points on Spacedle's rarity scale, which places it in the anomaly tier. Another 25 points would lift it into a rarer tier.
That score comes from 9 science badges — Variable star, Distant (over 1,000 light-years), Naked-eye visible, Blazing O-type star, Supergiant, Blue-white star, Blindingly luminous (Mv < −5) and Gently variable — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.