About this world
PSR B1257+12 d is a super-Earth orbiting PSR B1257+12, a star 1.96 thousand light-years from Earth. It is about 1.8 times the size of Earth (its size estimated from its mass) and holds 3.9 Earth masses. It completes an orbit every 98.2 days at 0.46 AU from its star.
At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 1992 by timing variations with Arecibo Observatory. Pulsar, eclipse or transit timings drift as an unseen companion tugs on them. PSR B1257+12 has 3 known planets; the others are PSR B1257+12 b and PSR B1257+12 c.