677 Aaltje is a main-belt minor planet orbiting the Sun, discovered by August Kopff at Heidelberg on January 18, 1909.
It was named after the Dutch singer Aaltje Noordewier-Reddingius.
Photometric observations during 2008 showed a rotation period of 16.6076 ± 0.0006 hours and a brightness variation of 0.30 ± 0.02 in magnitude.
However, 677 Aaltje is too large for its orbit to have been moved by more than about 0.01 AU over the lifetime of the Solar System.
What is more likely is that orbital interactions with the dwarf planet Ceres may have shifted it to the present-day orbit—the orbit of 677 Aaltje leads it into relatively close encounters with Ceres.