An eighth planet around Kepler-90 found by a neural network
A convolutional network re-examining Kepler light curves recovered transit signals the standard pipeline had ranked below threshold, yielding Kepler-90i and making Kepler-90 the first star besides the Sun known to host eight planets.
- Model
- Convolutional neural network (AstroNet)
- Field
- Astronomy
- Date
- 2017-12-14
- Human collaborators
- Christopher Shallue, Andrew Vanderburg
What was found
The network was trained on 15,000 previously vetted Kepler signals to separate genuine transits from false positives, then pointed at 670 stars already known to host multiple planets, searching the weak signals the automated pipeline had discarded. It surfaced Kepler-90i (about 30% larger than Earth, orbiting every 14.4 days, with a surface hot enough to rival Mercury) and Kepler-80g, which completes a five-planet resonant chain. Published in The Astronomical Journal.
Novelty check
Machine classification of Kepler transit candidates already existed in the pipeline (Autovetter, Robovetter). What was new was training a network to vet signals below the pipeline's detection threshold and getting confirmable planets out of the discard pile.
Caveats and known objections
The network vetted candidate signals; the transit search, the follow-up and the statistical validation were conventional. "First system with as many planets as ours" is a statement about what has been detected, not what exists. Detection is heavily biased toward close-in planets, and all of Kepler-90's known planets orbit within roughly Earth's distance from its star. The 670-star search produced two new planets in total.
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Entry history (1 event)
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Cite this entry
whataifound.org. (2017). An eighth planet around Kepler-90 found by a neural network. whataifound.org: A Registry of AI Scientific and Mathematical Discoveries. https://whataifound.org/finding/2017-12-14-kepler-90iBibTeX
@misc{whataifound-google-2017-90i,
title = {An eighth planet around Kepler-90 found by a neural network},
author = {{whataifound.org}},
year = {2017},
howpublished = {whataifound.org: A Registry of AI Scientific and Mathematical Discoveries},
note = {Result by Google Brain / University of Texas at Austin. Verification: Peer reviewed. Autonomy: Search scaffold.},
url = {https://whataifound.org/finding/2017-12-14-kepler-90i}
}