KOI-1843.03: A Year In 4.2 Hours
Terrestrial around Kepler-974
It is 0.61 times Earth's radius, closest in size to Mars, and 8.0 times Earth's mass. A year there lasts 4.2 hours. The host star Kepler-974 runs at 3584 K with 0.46 times the Sun's mass.
4.2hours: one full year, start to finish
Radius
0.61 Earth radii
Mass
8.0 Earth masses
One year
4.2 hours
Host star
Kepler-974 at 3584 K
Distance
438 light-years
Starlight blocked
0.015% at each transit
What the archive holds on this planet
A size. Yes.
A weight, not just a width. Yes.
A density, the one clue to composition. No.
A semi-major axis. No.
An observed temperature. No.
The shape of the orbit. No.
What a crossing measures
How deep the star dims fixes the planet's size relative to it.
The size came from a crossing, the mass did not. That pairing is uncommon and it is what lets anyone say whether this is rock or gas.
Found by Kepler in 2013. 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.
Kepler-974 has 2 known planets. Multi-planet systems are where orbital dynamics can be measured rather than assumed.
