Gas giant
The smallest known extrasolar planet that is likely a "gas planet" is Kepler-138d, which has the same mass as Earth but is 60% larger and therefore has a density that indicates a thick gas envelope.
73 Klytia
Klytia ( ; minor planet designation: 73 Klytia) is a main-belt asteroid. It was the second and last asteroid discovery by the prolific comet discoverer Horace Tuttle, on April 7, 1862. It is named after Clytia, who loved Apollo in Greek mythology. Of the first one hundred numbered asteroids, Klytia is the smallest.