Planets found by eclipse timing
17 of the confirmed exoplanets in this catalog, 0.3% of the total, were found by eclipse timing variations: timing an eclipsing binary and watching the clock drift, the first of them in 2009.
Some binary stars eclipse each other on a schedule as regular as a metronome. A planet orbiting the pair pulls the whole binary back and forth, so the eclipses arrive early for years and then late for years as the light travel time changes. The pattern in that drift encodes the planet's orbit and mass.
The systems this works on are exotic: usually a hot stripped stellar core paired with a small companion, remnants of a phase in which the two stars shared an envelope. Whether the planets found this way survived that violence or formed afterwards from its debris is an open and interesting question.
The drift can have other causes. Magnetic cycles in one of the stars can change its shape slightly and shift the eclipse timing on decade timescales, which mimics a planet. Several claimed eclipse-timing planets have been withdrawn for this reason, and the ones this catalog marks as disputed stay flagged.
| # | World | Distance | Discovered |
|---|---|---|---|
| 1 | RR Cae b | 69.1 ly | 2012 |
| 2 | DE CVn b | 99.6 ly | 2018 |
| 3 | HU Aqr AB b | 627 ly | 2011 |
| 4 | HU Aqr AB c | 627 ly | 2011 |
| 5 | UZ For b | 781 ly | 2011 |
| 6 | UZ For c | 781 ly | 2011 |
| 7 | DP Leo b | 997 ly | 2009 |
| 8 | 2MASS J19383260+4603591 b | 1,293 ly | 2015 |
| 9 | Kepler-451 c | 1,293 ly | 2022 |
| 10 | Kepler-451 d | 1,293 ly | 2022 |
| 11 | NN Ser c | 1,682 ly | 2010 |
| 12 | NN Ser d | 1,682 ly | 2010 |
| 13 | NY Vir b | 1,774 ly | 2011 |
| 14 | NY Vir c | 1,774 ly | 2019 |
| 15 | NSVS 14256825 b | 2,677 ly | 2019 |
| 16 | Kepler-1660 AB b | 3,876 ly | 2023 |
How does eclipse timing find planets around binary stars?
17 of the confirmed exoplanets in this catalog, 0.3% of the total, were found by eclipse timing variations: timing an eclipsing binary and watching the clock drift, the first of them in 2009.
What was the first planet found by eclipse timing variations?
DP Leo b, confirmed in 2009. The method has found 17 confirmed worlds since, the most recent of them in 2023.
What can this method not see?
The drift can have other causes. Magnetic cycles in one of the stars can change its shape slightly and shift the eclipse timing on decade timescales, which mimics a planet. Several claimed eclipse-timing planets have been withdrawn for this reason, and the ones this catalog marks as disputed stay flagged.
Why are eclipse-timing planets often disputed?
Because a drifting eclipse clock has more than one possible cause. A magnetic cycle in one star can produce a similar decades-long wobble, and some proposed planetary solutions turned out to be dynamically unstable. The site flags disputed detections rather than quietly dropping them.
Can a planet survive the death of both its stars?
Some appear to have. A planet far enough out can ride through a star's expansion and mass loss, ending up on a wider orbit around the remnant. Others may be second-generation worlds, built from the material the dying stars threw off.
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