RA 171.2749° · Dec 41.0280° · exoplanet
9 more points to reach Epic.
HAT-P-21 b is a rare exoplanet. It lies about 904.4 light-years from Earth, shines at apparent magnitude 11.46, has spectral type G3 and has an equilibrium temperature near 1,367 K.
Its surface is almost certainly an ocean of molten rock, kept liquid by the star it hugs.
At apparent magnitude 11.46, a small backyard telescope will bring it into view.
Like any astronomical target, HAT-P-21 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.
HAT-P-21 b scores 41 points on Spacedle's rarity scale, which places it in the rare tier. Another 9 points would lift it into a rarer tier.
That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Lava world, Tidally locked 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.