Reading Patientia’s light curve

What 34 years of brightness measurements reveal about a large, quiet asteroid.

Published 2026-10-23

Most asteroids are too small or far away to show a disk in ordinary telescopes. Instead, astronomers study how their brightness changes over time — the light curve.^[4]

Decades of data

Patientia was studied photometrically many times between 1969 and 2003. Combining these observations gave an irregular light curve with a synodic period of 9.730 ± 0.004 hours.^[2] JPL lists a rotation period of 9.727 hours.^[1]

Small swings

The brightness varies by only 0.05–0.10 magnitude each rotation.^[2] Elongated asteroids can vary by a magnitude or more as they turn end-on and side-on. A small amplitude suggests Patientia is fairly even in shape, or that we view it close to pole-on.^[4]

Why “synodic”?

A synodic period is measured relative to the changing Earth–Sun geometry, so it can differ slightly from the true (sidereal) rotation period. Many observations at different viewing angles help pin down both and the pole direction.^[4]

Try it yourself

Amateur photometry contributes to asteroid light curves. With a camera on a telescope you can record brightness over a night and plot the change — a good project for a bright, slowly varying target.

Numbered citations link to the sources list on the Patientia overview page.