RA 234.2195° · Dec -67.4847° · star
6 more points to reach Rare.
HD 138521 is an uncommon variable star. It lies about 807.3 light-years from Earth, sits in the constellation TrA, shines at apparent magnitude 8.06 and has spectral type B9IV.
Its spectrum reads B9IV — a blue-white B-type star, with a surface tens of thousands of degrees hot and a life measured in tens of millions of years.
Look for HD 138521 in the constellation TrA. At apparent magnitude 8.06, it is an easy target for binoculars.
Like any astronomical target, HD 138521 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.
HD 138521 scores 28 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 6 points would lift it into a rarer tier.
That score comes from 6 science badges — Variable star, Hot blue B-type star, Subgiant (leaving the main sequence), Blue-white star, Gently variable and A named variable star — 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.