Kepler-453 b: Habitable Zone, 241-Day Year
Ice giant around Kepler-453
It is 6.20 times Earth's radius, closest in size to Saturn, and 16.0 times Earth's mass. A year there lasts 240.50 days, on an orbit 2.0 times Mercury's distance from the Sun. Its equilibrium temperature is 250 K (derived from the star rather than measured), in the range where liquid water is possible. The host star Kepler-453 runs at 5527 K with 0.94 times the Sun's mass.
What this planet has and has not got
Inside the habitable zone, computed from the star's luminosity. Yes.
A measured mass, not just a radius. Yes.
A measured temperature rather than one derived from the star. No.
Any detection of an atmosphere. Not recorded in the archive.
Radius
6.20 Earth radii
Mass
16.0 Earth masses
Equilibrium temperature
250 K (derived)
One year
240.50 days
Orbit radius
0.7903 AU
Host star
Kepler-453 at 5527 K
Distance
1444 light-years
Starlight blocked
0.465% at each transit
What you get from the shadow
How deep the star dims fixes the planet's size relative to it.
The archive lists no measured equilibrium temperature for this planet. The 250 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.
Two independent measurements sit behind this page: a dip in starlight for the size, and something else entirely for the mass. Together they make a density.
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.
Kepler-453 b sits in the habitable zone on the arithmetic alone. That says \
where it orbits, not what it is like. What would you want measured next before calling it promising?
