It was discovered on 18 September 1939, by Finnish astronomer Yrjö Väisälä at Turku Observatory, Southwest Finland.
[2] Pielinen is a member of the Flora family, a large group of stony S-type asteroids.
It orbits the Sun in the inner main-belt at a distance of 1.8–2.6 AU once every 3 years and 3 months (1,195 days).
[4][5][6] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the largest member and namesake of this family – and calculates a diameter of 7.82 kilometers, with an absolute magnitude of 12.7.
[3] This minor planet is named after Pielinen, Finland's fourth largest lake in Finnish Karelia.