139P/Väisälä–Oterma is a periodic comet in the Solar System. When it was discovered in 1939 it was not recognized as a comet and designated as asteroid 1939 TN.
References
External links Orbital simulation from JPL (Java) / Horizons Ephemeris 139P/Vaisala-Oterma – Seiichi Yoshida @ aerith.net 139P at Kronk's Cometography