Kepler-444 is a five planet system around a host-star approximately 11 billion years old .
The five transiting planets all have sub-Earth radii and are in a compact configuration with orbital periods between 3 and 10 days .
Here we present a transit-timing analysis of the system using the full Kepler data set in order to determine the masses of the planets .
Two planets , Kepler-444 d ( M _ { \mathrm { d } } = 0.036 ^ { +0.065 } _ { -0.020 } M _ { \oplus } ) and Kepler-444 e ( M _ { \mathrm { e } } = 0.034 ^ { +0.059 } _ { -0.019 } M _ { \oplus } ) , have confidently detected masses due to their proximity to resonance which creates transit timing variations .
The mass ratio of these planets combined with the magnitude of possible star-planet tidal effects suggests that smooth disk migration over a significant distance is unlikely to have brought the system to its currently observed orbital architecture without significant post-formation perturbations .