RA 291.4689° · Dec 40.3437° · exoplanet
10 more points to reach Epic.
Kepler-398 d is a rare exoplanet. It lies about 578.5 light-years from Earth, shines at apparent magnitude 13.5, has an equilibrium temperature near 636 K and spans roughly 0.88 Earth radii.
Genuinely comparable to Earth in size. Worlds in this narrow band are the ones every next-generation telescope is being pointed at.
At apparent magnitude 13.5, it takes a larger telescope or a long-exposure image to capture.
Like any astronomical target, Kepler-398 d 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.
Kepler-398 d scores 40 points on Spacedle's rarity scale, which places it in the rare tier. Another 10 points would lift it into a rarer tier.
That score comes from 5 science badges — Confirmed exoplanet, Earth-sized, Tidally locked, Multi-planet system and Found by Kepler — 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.