Kepler-150 f: Habitable Zone, 637-Day Year
Mini-neptune around Kepler-150
It is 3.64 times Earth's radius, closest in size to Neptune. A year there lasts 637.21 days, on an orbit 3.2 times Mercury's distance from the Sun. Its equilibrium temperature is 208 K (derived from the star rather than measured), in the range where liquid water is possible. The host star Kepler-150 runs at 5528 K with 0.97 times the Sun's mass.
Where this planet stands on each testable criterion
Orbits within the zone where liquid water could persist. Yes.
A measured mass, not just a radius. No.
A measured temperature rather than one derived from the star. No.
Any detection of an atmosphere. Not recorded in the archive.
Kepler-150 from the inside out
Orbit
/
Planet
Radius
3.64 Earth radii
Equilibrium temperature
208 K (derived)
One year
637.21 days
Orbit radius
1.2400 AU
Host star
Kepler-150 at 5528 K
Distance
2906 light-years
Starlight blocked
0.136% at each transit
What the dip tells you
How deep the star dims fixes the planet's size relative to it.
The archive lists no measured equilibrium temperature for this planet. The 208 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.
Everything known here comes from how much light went missing. That fixes the size and leaves the mass entirely open.
Kepler-150 has 5 known planets. Systems like this are the ones where architecture can be studied instead of guessed at.
Found by Kepler in 2017. 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-150 f 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?
