← All detection methods · Exoplanet Archive
No dip needed — the system's total light rises and falls as the planet turns.
A planet orbiting very close to its star is heated fiercely on one side and shows us varying amounts of that hot, lit face as it goes around — like lunar phases, in light we can measure but not resolve.
The system's combined brightness therefore rises and falls smoothly, once per orbit. No transit is required; the planet need never cross the star at all.
Two further effects ride along: the star is tidally distorted into an ellipsoid by the planet's pull, changing its apparent area twice per orbit, and relativistic beaming brightens the star slightly as it moves toward us.
The signals are of order parts per million, so in practice this needs a space telescope staring at one field for months.
Three effects with different periods in the same light curve — separating them is what makes the method work, and what makes it hard.
| Landmark discovery | Kepler-70 b and c — extreme cases orbiting a hot subdwarf, found in Kepler photometry. |
| Instruments | Kepler, CoRoT, TESS, CHEOPS |
| Archive name | Orbital Brightness Modulation — the value in NASA's discoverymethod field |