RA 282.2124° · Dec -12.5563° · star
7 more points to reach Rare.
HD 173991 is an uncommon star. It sits in the constellation Sct, shines at apparent magnitude 9.01 and has spectral type B2Ib/II.
Its spectrum reads B2Ib/II — 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 173991 in the constellation Sct. At apparent magnitude 9.01, a small backyard telescope will bring it into view.
Like any astronomical target, HD 173991 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 173991 scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.
That score comes from 3 science badges — Star, Hot blue B-type star and Supergiant — 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.