A Planet Observed II

"A Tragedy of Errors."

Roan Tom has homed on radio signals carrying human voices speaking Anglic words although the signals had broken off several light-years away. He observes a planet from space:

green, blue and brown with an underlying red;
many seas but no ocean;
clouds;
extensive southern polar cap;
north pole almost completely melted in summer;
two small moons;
habitable according to the spectroscope;
the only possible source of the radio signals;
axial tilt 10 degrees;
diameter 6810 kilometers;
mass 0.15 Terran;
should be too small to be habitable.

An sf author invents a mystery and his character solves it.