4veeps

AI has found an 8-planetsystem like ours in Keplerdata

In 2013, the space telescope found seven worlds orbiting
Kepler 90
BY MARIA TEMMING 8:10PM, DECEMBER 14, 2017

THIRD ROCK The keen eye of an AI program discovered that
the star system Kepler 90, illustrated here, has an eighth world
(dubbed Kepler 90i), which was previously overlooked in
exoplanet searches.

Our solar system is no longer the sole record-holder for most
known planets circling a star.
An artificial intelligence algorithm sifted through data from the
planet-hunting Kepler space telescope and discovered a
previously overlooked planet orbiting Kepler 90 — making it
the first star besides the sun known to host eight planets.
This finding, announced in a NASA teleconference December
14, shows that the kinds of clever computer codes used to
translate text and recognize voices can also help discover
strange new worlds.
The discovery, also reported in a paper accepted to the
Astronomical Journal , can also help astronomers better
understand the planetary population of our galaxy. “Finding
systems like this that have lots of planets is a really neat way
to test theories of planet formation and evolution,” says Jeff
Coughlin, an astronomer at the SETI Institute in Mountain
View, Calif., and NASA’s Ames Research Center in Moffett
Field, Calif.
Kepler 90 is a sunlike star about 2,500 light-years from Earth
in the constellation Draco. The latest addition to Kepler 90’s
planetary family is a rocky planet about 30 percent larger than
Earth called Kepler 90i. It, too, is the third planet from its sun
— but with an estimated surface temperature higher than 400°
Celsius, it’s probably not habitable.
Story continues below graphic
MOVIN’ ON UP Kepler 90, which previously shared the
runner-up spot with TRAPPIST-1, is now tied with our

solar system for the planetary family with the most
members.

WENDY STENZEL/AMES RESEARCH CENTER/NASA
The seven previously known planets in this system range from
small, rocky worlds like Kepler 90i to gas giants, which are all
packed closer to their star than Earth is to the sun. “It’s very
possible that Kepler 90 has even more planets,” study
coauthor Andrew Vanderburg, an astronomer at the University
of Texas at Austin, said in the teleconference. “There’s a lot
of unexplored real estate in the Kepler 90 system.”
Astronomers have identified over 2,300 new planets in Kepler
data by searching for tiny dips in a star’s brightness when a
planet passes in front of it. Kepler has collected too much
data for anyone to go through it all by hand, so humans or
computer programs typically only verify the most promising
signals of the bunch. That means that worlds that produce
weaker light dips — like Kepler 90i — can get passed over.
Vanderburg and Christopher Shallue, a software engineer at
Google in Mountain View, Calif., designed a computer code
called a neural network, which mimics the way the human
brain processes information, to seek out such overlooked
exoplanets.
Subtle signal
When a planet crosses in front of its star, Kepler sees a small
dip in starlight (as indicated by the white line). But if that
signal is weak — like the light reading produced by Kepler 90i
(blue dots) — it can be hard to distinguish from meaningless
noise.
Researchers previously automated Kepler data analysis by
hard-coding programs with rules about how to detect bona
fide exoplanet signals, Coughlin explains. Here, Vanderburg
and Shallue provided their code with more than 10,000 Kepler
signals that had been labeled by human scientists as either
exoplanet or non-exoplanet signals. By studying these
examples, the neural network learned on its own what the
light signal of an exoplanet looked like, and could then pick
out the signatures of exoplanets in previously unseen signals.
The fully trained neural network examined 670 star systems
known to host multiple planets to see whether previous
searches had missed anything. It spotted Kepler 90i, as well
as a sixth, Earth-sized planet around the star Kepler 80. This
feat marks the first time a neural network program has
successfully identified new exoplanets in Kepler data, Jessie
Dotson, an astrophysicist at NASA’s Ames Research Center
said at the teleconference.
Vanderburg and Shallue now plan to apply their neural
network to Kepler’s full cache of data on more than 150,000
stars, to see what other unrecognized exoplanets it might turn
up.
Coughlin is also excited about the prospect of using artificial
intelligence to assess data from future exoplanet search
missions, like NASA’s TESS satellite set to launch next year.
“The hits are going to keep on coming,” regarding potential
exoplanet signals, he says. Having self-taught computer
programs help humans slog through the data could
significantly speed up the rate of scientific discovery.
Tight-knit
The Kepler 90 solar system is like a cinched-up version of our
own: Small rocky planets hug the star most tightly, while
larger planets hang back. But as seen here, all eight planets’
orbits are packed closer to their star than Earth is to the sun.

WENDY STENZEL/AMES RESEARCH CENTER/NASA, A
VANDERBURG/UT AUSTIN
Citations
C. Shallue and A. Vanderburg. Identifying exoplanets with
deep learning: a five planet resonant chain around Kepler-80
and an eighth planet around Kepler-90 . Accepted for
publication in The Astronomical Journal .
Further Reading
L. Grossman. Kepler shows small exoplanets are either super-
Earths or mini-Neptunes . Science News Online, June 19, 2017.
C. Crockett. Kepler telescope doubles its count of known
exoplanets. Science News. Vol. 189, June 11, 2016, p. 12.
C. Crockett. New telescopes will search for signs of life on
distant planets . Science News . Vol. 189, April 30, 2016, p. 32.
A. Grant. New exoplanet: Big Earth or small Neptune? Science
News. Vol. 188, August 22, 2015, p. 32.
C. Crockett. Sun shines new life on Kepler space
telescope. Science News . Vol. 185, June 28, 2014, p. 7.