:INFO
Terrestrial around KOI-3503
It is 1.21 times Earth's radius, closest in size to Earth, and 10.4 times Earth's mass, at 10.00 g/cm3, denser than Earth. A year there lasts 31.83 days. Its equilibrium temperature is 686 K, hotter than any desert. The host star KOI-3503 runs at 6001 K with 0.86 times the Sun's mass.

:COUNTER
10.0 g/cm3: denser than iron at Earth surface pressure

:STATS
[icon:TARGET] Radius | 1.21 Earth radii
[icon:CHART] Mass | 10.4 Earth masses
[icon:FIRE] Equilibrium temperature | 686 K (measured)
[icon:CLOCK] One year | 31.83 days
[icon:STAR] Host star | KOI-3503 at 6001 K
[icon:USERS] Distance | 2893 light-years
[icon:TRENDING_DOWN] Starlight blocked | 0.008% at each transit

:CHECKLIST
What the archive holds on this planet
[ ] A radius from transit photometry. Yes.
[ ] A mass. Yes.
[ ] A density, which decides rock or gas. Yes.
[ ] A semi-major axis. No.
[ ] A temperature someone observed rather than calculated. Yes.
[ ] The shape of the orbit. No.

:PATH
What a crossing measures
Block a known fraction of a known star and you have measured a width.

:NOTE
Found by Kepler in 2021. 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
KOI-3503 has 2 known planets. Multi-planet systems are where orbital dynamics can be measured rather than assumed.

:NOTE
A transit gives the radius and a separate measurement gives the mass. Having both is what makes a density, and a density is the only clue to composition at this range.

:LINK
https://exoplanetarchive.ipac.caltech.edu/overview/KOI-3503%20c
NASA Exoplanet Archive: source data, including the values not used here