:INFO Terrestrial around Kepler-444 It is 0.50 times Earth's radius, closest in size to Mars. A year there lasts 4.55 days, on an orbit 8 times closer to its star than Mercury is to the Sun. Its equilibrium temperature is 874 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 Kepler-444 from the inside out 1 0.042 AU 2 0.049 AU 3 0.060 AU 4 0.070 AU 5 0.081 AU :STATS [icon:TARGET] Radius | 0.50 Earth radii [icon:FIRE] Equilibrium temperature | 874 K (derived) [icon:CLOCK] One year | 4.55 days [icon:BOLT] Orbit radius | 0.0488 AU [icon:STAR] Host star | Kepler-444 at 5046 K [icon:USERS] Distance | 119 light-years [icon:TRENDING_DOWN] Starlight blocked | 0.004% at each transit :PATH What you get from the shadow How deep the star dims fixes the planet's size relative to it. :COUNTER 0.50x Earth: smaller than Venus :CHECKLIST What has been measured here and what has not [ ] A measured radius. Yes. [ ] A mass. No. [ ] A density, the one clue to composition. No. [ ] How far out it orbits. Yes. [ ] An observed temperature. No. [ ] An eccentricity, so we know if the orbit is a circle. Yes. :NOTE The archive lists no measured equilibrium temperature for this planet. The 874 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. :NOTE Found by Kepler in 2015. The mission traded sky coverage for depth, holding one view for years. That bias runs through its whole catalogue and through this planet's discovery. :NOTE.half Found by watching its star dim as it crossed in front. That measures size and not weight, which is why there is a radius here and no mass. :NOTE.half Kepler-444 has 5 known planets. Systems like this are the ones where architecture can be studied instead of guessed at. :THREAD :LINK https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-444%20c NASA Exoplanet Archive: source data, including the values not used here