Planets found by orbital brightness modulation
9 of the confirmed exoplanets in this catalog, 0.1% of the total, were found by orbital brightness modulation: reading a system's brightness as it changes shape through an orbit, the first of them in 2011.
A planet very close to its star changes the system's total brightness even when nothing eclipses anything. The planet shows phases like the Moon, its dayside glows with re-radiated heat, and its gravity raises a tidal bulge on the star that turns the star slightly brighter side-on than end-on. Together these produce a smooth brightness variation on the orbital period.
Because it needs no eclipse geometry, this method can detect planets whose orbits are tilted enough to miss a transit entirely. It works only for the extreme cases, hot giants on very short orbits, where the effects are large enough to see above the noise, and it emerged from the same precise photometry that made the transit era possible.
Only the most extreme close-in giants produce a signal at all, and stellar variability can imitate one. It is a small, specialised corner of the catalog rather than a general-purpose technique.
| # | World | Distance | Discovered |
|---|---|---|---|
| 1 | KIC 5479689 b | 1,484 ly | 2021 |
| 2 | KIC 8121913 b | 2,307 ly | 2021 |
| 3 | KIC 10068024 b | 2,352 ly | 2021 |
| 4 | Kepler-76 b | 2,684 ly | 2013 |
| 5 | KOI-55 b | 4,015 ly | 2011 |
| 6 | KOI-55 c | 4,015 ly | 2011 |
| 7 | KIC 10001893 b | 5,456 ly | 2014 |
| 8 | KIC 10001893 c | 5,456 ly | 2014 |
| 9 | KIC 10001893 d | 5,456 ly | 2014 |
What is orbital brightness modulation?
9 of the confirmed exoplanets in this catalog, 0.1% of the total, were found by orbital brightness modulation: reading a system's brightness as it changes shape through an orbit, the first of them in 2011.
What was the first planet found by orbital brightness modulation?
KOI-55 b, confirmed in 2011. The method has found 9 confirmed worlds since, the most recent of them in 2021.
What can this method not see?
Only the most extreme close-in giants produce a signal at all, and stellar variability can imitate one. It is a small, specialised corner of the catalog rather than a general-purpose technique.
How can a planet be detected without an eclipse?
By its phases and its pull. The planet's dayside glows, the illuminated fraction we see changes through the orbit, and the planet's gravity distorts the star into a slight ellipsoid whose brightness depends on its orientation. All three vary on the orbital period.
Is this method related to the transit method?
It uses the same instruments and the same kind of data: a long, precise brightness curve. The difference is what is being read out of it, a smooth periodic modulation rather than a sharp repeating dip.
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