RA 53.0393° · Dec 42.7493° · star
6 more points to reach Common.
HD 21751 is a trash star. It lies about 929.2 light-years from Earth, sits in the constellation Per, shines at apparent magnitude 7.27 and has spectral type B9.
Its spectrum reads B9 — 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 21751 in the constellation Per. At apparent magnitude 7.27, it is an easy target for binoculars.
Like any astronomical target, HD 21751 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 21751 scores 9 points on Spacedle's rarity scale, which places it in the trash tier. Another 6 points would lift it into a rarer tier.
That score comes from 2 science badges — Star and Hot blue B-type 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.