Studies of exoplanet demographics require large samples and precise constraints on exoplanet host stars .
Using the homogeneous Kepler stellar properties derived using Gaia Data Release 2 by [ ] , we re-compute Kepler planet radii and incident fluxes and investigate their distributions with stellar mass and age .
We measure the stellar mass dependence of the planet radius valley to be d \log R _ { \mathrm { p } } / d \log M _ { \star } = 0.26 ^ { +0.21 } _ { -0.16 } , consistent with the slope predicted by both photoevaporation ( 0.24–0.35 ) and core-powered mass-loss ( 0.33 ) .
We also find first evidence of a stellar age dependence of the planet populations straddling the \added radius valley .
Specifically , we determine that the \replaced ratiofraction of super-Earths \added ( 1–1.8 \mathrm { R _ { \oplus } } ) to sub-Neptunes \added ( 1.8–3.5 \mathrm { R _ { \oplus } } ) increases from \replaced 0.68 \pm 0.070.61 \pm 0.09 at young ages ( < 1 Gyr ) to \replaced 0.93 \pm 0.071.00 \pm 0.10 at old ages ( > 1 Gyr ) , consistent with the prediction by core-powered mass-loss that the mechanism shaping the radius valley operates over Gyr timescales .
We confirm the existence of planets within the hot super-Earth “ desert ” ( 2.2 < R _ { \mathrm { p } } < 3.8 \mathrm { R _ { \oplus } } , F _ { \mathrm { p } } > 650 \mathrm { F _ { \oplus } } ) and show that these \added planets are \added preferentially orbiting more evolved stars compared to other planets at similar incident fluxes .
In addition , we identify candidates for cool ( F _ { \mathrm { p } } < 20 \mathrm { F _ { \oplus } } ) inflated Jupiters , present a revised list of habitable zone candidates , and \replaced find tentative evidence that systems with multiple transiting planets are younger than those with a single transiting planetfind that the ages of single- and multiple-transiting planet systems are statistically indistinguishable .