Like Earth, Kepler-90i is the third rock from its sun - though it sits much closer, circling its star every 14.4 days.
The computers were coded to identify planets by analysing data from Kepler, in which the telescope had previously recorded signals from exoplanets.
"Today, Kepler confirms that stars can have large families of planets, just like our solar system", Paul Hertz, director of the US space agency NASA's Astrophysics Division said in a teleconference.
However, none of the planets are expected to be hospitable to life.
Kepler-90i is a rocky planet that is about 30 percent larger than the Earth. It is the first star known to support as many planets as are orbiting our own sun, and researchers believe that this is the first of many to come.
"Our solar system now is tied for most number of planets around a single star", NASA said in a statement. "You have small planets inside and big planets outside, but everything is scrunched in much closer", said Andrew Vanderburg, a NASA Sagan postdoctoral fellow at the University of Texas. Now, an eighth planet has been identified in this planetary system, making it tied with our own solar system in having the highest number of known planets.
The system can be called a twin because it is the first we have seen to have eight planets in its system aside from our own, and it was only with the AI's help that the eighth planet had been spotted after the system's initial discovery.
The planet was discovered in data from NASA's Kepler Space Telescope.
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Machine learning has previously been used in searches of the Kepler database, and this continuing research demonstrates that neural networks are a promising tool in finding some of the weakest signals of distant worlds. Until now the weaker signals have traditionally been missed using that method.
Vanderburg and Christopher Shallue, a senior software engineer with Google's research team Google AI, planned to apply their neural network to Kepler's full set of more than 150,000 stars.
Besides, he said that this information would be a "treasure trove" that other experts will be able to use fpr further research.
The researchers said they aren't sure why the Kepler-90 system has such a crowded field.
When the scientists finally tested their neural network on signals that it had not seen before, it correctly sorted the planets from the false positives a whopping 96% of the time, Shallue said. He also compared the finding of exoplanets to sifting through rocks with a fine sieve to find jewels.
What is Kepler-90i like? In the Kepler-80 system, they also found a sixth planet. Five of the six planets form a resonant chain, in which they are locked in orbit by mutual gravity. The latter is part of a six-planet star system located 1,000 light-years away.
Their research paper reporting these findings has been accepted for publication in The Astronomical Journal.
"Kepler has already shown us that most stars have planets", said Paul Hertz, director of NASA's Astrophysics Division in Washington.
NASA project scientist for the Kepler space telescope, Jessie Dotson said, "who knows what might be discovered, As the application of neutral networks to Kepler data matures", he further added, "I'm on the edge of my seat".