Eight Exoplanets Orbit Sun-Like Star Kepler-90

Lawrence Kim
December 16, 2017

In the Keplar-90 system, all the planets are squished in closer to their sun than Earth is close to ours.

Paul Hertz, director of NASA's Astrophysics Division in Washington, said that they expected these "exciting discoveries" lurking in the Kepler data they had archived.

These dips were identified with a new algorithm developed by Google which allows computers to teach themselves how to identify planets by analysing Kepler data. Google's TensorFlow platform has identified two previously missed planets orbiting faraway stars.

An artist's concept depicts select planetary discoveries made to date by NASA's Kepler space telescope.

NASA has named the new planet "Kepler-90i".

The next three planets beyond Kepler-90i - 90d, 90e and 90f - fall into a sub-Neptune size class and complete an orbit every 60, 92 and 125 days, respectively.

Christopher Shallue, an artificial intelligence researcher and senior software engineer at Google Al, and Andrew Vanderburg, an astronomer at the University of Texas at Austin, says that will continue their work by analyzing Kepler data on more than 150,000 other stars. "It does that by learning by example, so we train the model by giving it a large set of labelled examples so it can learn which patterns it can use to make the decision on whether the data is in one category or the other". This so-called "transit" method of exoplanet detection has proven very effective, but Kepler produces enormous volumes of data. Shallue and Vanderburg found that the artificial neural network identified such signals correctly 96 percent of the time.

The find sets a new record for the most exoplanets around a single star and, for the first time, ties with our own.

The Kepler Space Telescope has been searching the galactic sky for exoplanets, or planets outside our own Solar System, since it launched in 2009. NASA unveiled the discovery of the eighth known planet in the system, Kepler-90i, on December 14, 2017. It's a rocky planet 30% bigger than Earth, but with surface temperatures around 800°F (424°C), so unlikely to harbor life. In fact, their orbits are so comparatively small that seven of Kepler-90's eight planets would fit in between the Earth and the Sun.

Finally, scientists discover another star system with the same number of worlds than our Solar System.

But while we now know that Kepler-90 has the same number of orbiting planets as our Sun, the solar system is a poor candidate in the search for extraterrestrial life - or at least, life as we know it (especially compared to something like the planets that surround TRAPPIST-1).

'It's like sifting through rocks to find jewels.

If you want to search for planets among Kepler's weaker signals - which are far more numerous - then that haystack gets "much, much larger", he added.

That means, for instance, that they can only be used for astronomy in cases like Kepler where scientists have a huge set of planets and stars that have been confirmed.

Kepler-90 is similar to our own Sun, and not too far away either - it's located a mere 2,545 light-years from Earth in the constellation of Draco, the Kepler space observatory found. The one orbiting Kepler 90 (known as Kepler 90i) is particularly interesting.

Google used machine learning to analyse pre-existing data from Kepler.

"This will absolutely work alongside astronomers", Jessie Dotson, Kepler's project scientist at NASA's Ames Research Center in California's Silicon Valley, said in a press briefing.

Other reports by Click Lancashire

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