RA 51.8634° · Dec -57.1383° · star
4 more points to reach Uncommon.
HD 21721 is a common star. It lies about 1,598.8 light-years from Earth, sits in the constellation Ret, shines at apparent magnitude 9.02 and has spectral type K0/K1III.
Its spectrum reads K0/K1III — a K-type star. Orange K dwarfs are the marathon runners of the galaxy, burning steadily for tens of billions of years.
Look for HD 21721 in the constellation Ret. At apparent magnitude 9.02, a small backyard telescope will bring it into view.
Like any astronomical target, HD 21721 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 21721 scores 18 points on Spacedle's rarity scale, which places it in the common tier. Another 4 points would lift it into a rarer tier.
That score comes from 4 science badges — Star, Distant (over 1,000 light-years), Orange K-type star and Giant 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.