![Kepler-444 b: 0.40 Times Earth](https://cdn.slatesource.com/5/0/1/50186bcb-876c-4c2f-90ad-45bf7fcbb133.webp) # Kepler-444 b: 0.40 Times Earth - [Made in Slatesource](https://slatesource.com/@steph/kepler-444-b-0-40-times-earth) - By [Steph](https://slatesource.com/@steph) - Created on Sep 19, 2026 ## Terrestrial around Kepler-444 It is 0.40 times Earth's radius, closest in size to Mars. A year there lasts 3.60 days, on an orbit 9 times closer to its star than Mercury is to the Sun. Its equilibrium temperature is 944 K (derived from the star rather than measured), hot enough to melt lead. The host star Kepler-444 runs at 5046 K with 0.76 times the Sun's mass. journey·5 Planets # Kepler-444 from the inside out Orbit / Planet "terrestrial, 944 K. "terrestrial, 874 K. "terrestrial, 788 K. "terrestrial, 732 K. "terrestrial, 678 K. Radius 0.40 Earth radii Equilibrium temperature 944 K (derived) One year 3.60 days Orbit radius 0.0418 AU Host star Kepler-444 at 5046 K Distance 119 light-years Starlight blocked 0.002% at each transit What the dip tells you Block a known fraction of a known star and you have measured a width. **0.40x** Earth: smaller than Venus What the archive holds on this planet 0% A radius from transit photometry. Yes. A mass. No. A density, so rock and gas can be told apart. No. An orbital distance. Yes. An observed temperature. No. The shape of the orbit. Yes. The archive lists no measured equilibrium temperature for this planet. The 944 K quoted here is derived from the star's output and the orbital distance, assuming a third of the light is reflected. It is an estimate from two numbers, not an observation. Found by Kepler in 2015. Kepler's method needed repetition, not brightness. It could find small planets around faint stars, provided they came round quickly enough to be seen twice. Everything known here comes from how much light went missing. That fixes the size and leaves the mass entirely open. Kepler-444 has 5 known planets. A crowded system is worth more than the sum of its planets: the timing of each transit constrains the others. # Half the temperatures quoted for exoplanets are calculated from the star, not \\ measured at the planet. Should a page like this show them at all, or leave the field blank? No comments yet. Be the first. Log in to comment [Every parameter ever published for Kepler-444 b, at the NASA Exoplanet Archive](https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-444%20b?utm_source=slatesource)