148780 Altjira (provisional designation ) appears to be a triple or contact binary double classical Kuiper belt object. The secondary is large compared to the primary, approximately vs. . The lightcurve is quite flat (), which is indicative of a "quasi-spherical body with a homogeneous surface". The system mass is .
In 2008, Altjira was named after the Arrernte creation deity, Altjira (Alchera).
Its companion was discovered on 6 August 2006, from images taken by the Hubble Space Telescope. The secondary's orbit has the following parameters: semi-major-axis, ; period, ; eccentricity, ; and inclination, (retrograde). There is indirect evidence that Altjira may be an unresolved hierarchical triple system.