Planets found by transit timing

31 of the confirmed exoplanets in this catalog, 0.5% of the total, were found by transit timing variations: spotting a planet by the way it tugs a sibling's transits early or late, the first of them in 2011.

Worlds found
31
First, 2011
Kepler-19 c
Nearest, 31.7 ly
AU Mic d
How it works

A single planet transits like clockwork. Add a second planet and the two pull on each other, so each transit arrives slightly early or slightly late in a repeating pattern. Model that pattern and you can infer the unseen planet's mass and orbit without ever seeing it cross the star, which is how some worlds in well-studied multi-planet systems were found.

The method also does something no other technique manages easily: it weighs small planets. Timing variations depend on mass, so a system with several transiting planets can yield real masses for worlds far too light to produce a measurable stellar wobble. Several of the best-characterised small planets in the catalog have masses that came from timing rather than from spectroscopy.

What it cannot see

It needs a transiting planet to start with, and a second planet close enough to interact strongly. That combination is rare, which is why this method accounts for a few dozen discoveries rather than thousands, and it works best in compact systems near orbital resonance.

The nearest worlds found this way
#WorldDistanceDiscovered
1AU Mic d31.7 ly2023
2TOI-1266 d117 ly2025
3TOI-2015 c154 ly2025
4Kepler-138 e218 ly2022
5TOI-5624 f332 ly2026
6TOI-199 c334 ly2023
7TOI-201 c371 ly2025
8WASP-18 c403 ly2019
9TOI-1408 c455 ly2024
10Kepler-411 e501 ly2018
11WASP-126 c706 ly2019
12Kepler-19 c713 ly2011
13TOI-2202 c770 ly2021
14KOI-984 c824 ly2022
15Kepler-539 c1,002 ly2016
16TOI-1232 c1,072 ly2026
17TOI-4562 c1,108 ly2024
18TOI-4504 d1,117 ly2024
19Kepler-1513 c1,139 ly2023
20KOI-142 c1,229 ly2013
21Kepler-139 f1,275 ly2025
22Kepler-448 c1,303 ly2017
23KOI-319 c2,153 ly2014
24KOI-884 e2,165 ly2014
25Kepler-725 c2,474 ly2025

Showing the 25 nearest of 31 with a measured distance.

Common questions

How do transit timing variations reveal planets?

31 of the confirmed exoplanets in this catalog, 0.5% of the total, were found by transit timing variations: spotting a planet by the way it tugs a sibling's transits early or late, the first of them in 2011.

What was the first planet found by transit timing variations?

Kepler-19 c, confirmed in 2011. The method has found 31 confirmed worlds since, the most recent of them in 2026.

What can this method not see?

It needs a transiting planet to start with, and a second planet close enough to interact strongly. That combination is rare, which is why this method accounts for a few dozen discoveries rather than thousands, and it works best in compact systems near orbital resonance.

How early or late does a transit arrive?

Usually seconds to minutes against a period of days, though strongly interacting systems can shift by hours. Detecting it requires many transits measured to high precision, which is why it emerged from long space-telescope campaigns.

Can timing variations weigh a planet?

Yes, and that is their real value. The size of the timing shift depends directly on the tugging planet's mass, so a system with several transiting planets gives masses for worlds too small for any other method to weigh.

Keep exploring: every detection method · discoveries by year