RA 51.6403° · Dec -43.6137° · exoplanet
12 more points to reach Rare.
HD 21520 b is an uncommon exoplanet. It lies about 258.3 light-years from Earth, shines at apparent magnitude 9.17, has an equilibrium temperature near 637 K and spans roughly 2.7 Earth radii.
It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.
At apparent magnitude 9.17, a small backyard telescope will bring it into view.
Like any astronomical target, HD 21520 b 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 21520 b scores 22 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 12 points would lift it into a rarer tier.
That score comes from 4 science badges — Confirmed exoplanet, Sub-Neptune, Found by TESS and Orbits a Sun-like 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.