839 Valborg is a mid-sized S-type Eunomian asteroid. Its diameter is about 20 km, its albedo of 0.353 is very high for an asteroid. Its rotation period is 10.366 hours.
References
External links , Palmer Divide Observatory, B. D. Warner (2005) Asteroid Lightcurve Database (LCDB), query form (info ) Dictionary of Minor Planet Names, Google books Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center