Amateur scientists find niche in locating new planets

Jun 13, 2012 By Brian Jacobsmeyer
The field of view for the Kepler spacecraft, which is collecting data for the search for exoplanets. Credit: Carter Roberts

Over the past decade, scientists have found evidence of hundreds of planets orbiting stars outside our solar system. A group of volunteers has also joined the search, and they have found several additional planets that initially fell through the cracks.

Exoplanets can be detected through a variety of ways, and scientists have increasingly looked for small, regularly repeating dips in light from a star-- a sign of passing in front of, or transiting, their home star. This same happened in our own solar system earlier this month when Earth-based viewers saw the for the last time this century.

But the sheer number of exoplanets means there's plenty of transits to track; consequently, scientists have acquired huge amounts of data to process. That’s partly why a research team at Yale University has recruited over 150,000 volunteers to help sort through publicly released data from the Kepler space telescope.

Called Planet Hunters, the project has led to the discovery of several new planets while also confirming many findings made by Kepler scientists. Earlier this year, project leaders unveiled two new exoplanet candidates that NASA’s computer data crunching failed to detect.

Most recently, 24,000 of the volunteers helped find seven more exoplanets that computer algorithms initially missed. Although updated data-processing algorithms detected these planets, scientists working to refine the algorithms have found the citizen volunteers' contributions invaluable.

"Firstly, it's educational and engaging. More importantly, it's having a real scientific impact," said Thomas Barclay, a research scientist at the NASA Ames Research Center who works on the algorithms used to find exoplanets with Kepler data.

After a brief tutorial, Planet Hunter volunteers can peruse light curves -- graphs of a star's light intensity -- with 30 days of Kepler data on the project's website. When enough flag a potential planet candidate, the project scientists review this pared down data before formally recognizing a new alien world.

Although planet candidates detected by algorithms are eventually scrutinized visually, relying entirely on visual detection from the beginning has its advantages. Planet Hunters can identify planets with subtle orbital meanderings that may fly under a computer program's radar.

For instance, neighboring planets can tug on an exoplanet, leading to slight changes in its orbit around a star, and algorithms might miss this difference.  Also, planets revolving around binary stars -- a set of two stars that orbit each other -- can be easier to detect by sight rather than with algorithms.

"You can never underestimate how important the human eye is at finding things," said Barclay.

Even the relatively untrained eye can be an effective planet detector. Volunteers of all ages have contributed to the Planet Hunters project, including participants as young as 13. Don’t be fooled by the volunteers' lack of experience, however. Citizen scientists detected 85 percent of large exoplanets in the data, according to a recent analysis accepted for publication in the Astrophysical Journal.

To test the efficiency of the planet hunters, the project leaders injected simulated exoplanet transits into the Planet Hunters datasets, unbeknownst to the volunteers. Because the scientists knew these simulations looked like actual transits, they could evaluate the ’ detection ability.

While the citizen scientists found most large exoplanets, they had more difficulty detecting smaller Earth-sized planets. Algorithms are better at finding tiny dips in light from smaller planets when visual detection isn’t sensitive enough.

"There's a niche for Planet Hunters," said Meg Schwamb, an astrophysicist at Yale University and lead author of Planet Hunters' most recent analysis. "We're very sensitive to large planets."

As scientists and citizens both race to find exoplanets with similar sizes and orbits to Earth, they'll be using a variety of methods. Before scientists detected the first transiting exoplanet in 1999, they looked for slight wobbles in distant stars that indicated a planet was exerting a very small gravitational pull, and this method has remained popular.

Telescopes can now directly image as well, and this method will become more important in coming years according to Jonathan Fortney, an exoplanet researcher at the University of California Santa Cruz. Even if new detection methods flourish, however, Fortney believes Planet Hunters will continue to contribute valuable findings.

"I think the citizen science stuff is incredibly interesting, especially in astronomy," said Fortney. "There’s a big amateur community."

Regardless of the method used, scientists are anxiously awaiting confirmation of a cosmic home away from home. Planet Hunters may not be the first group to find a truly Earth-like planet outside of our solar system, but scientists are using every tool available.

"I think we're only a year or 18 months away from finding an analog," said Barclay. "We're getting very close."

Explore further: Black hole chokes on a swallowed star

Related Stories

Volunteers to hunt for 'lost planets'

Dec 20, 2010

(PhysOrg.com) -- The public are being asked to help Oxford University astronomers find planets orbiting other stars which may have been 'lost' in the data from over 100,000 stars. Volunteers could even find ...

On the trail of new planets

Sep 29, 2011

(PhysOrg.com) -- A project in which volunteers hunt online for new planets NASA may have missed is publishing its first results which show some remarkable finds.

Citizen scientists join search for Earth-like planets

Dec 16, 2010

(PhysOrg.com) -- Web users around the globe will be able to help professional astronomers in their search for Earth-like planets thanks to a new online citizen science project called Planet Hunters that launches ...

An exoplanet orbiting a double star

Oct 03, 2011

(PhysOrg.com) -- The Kepler satellite, which has now reported the detection of 1781 candidate exoplanets (a planet around a star other than the sun), has also discovered that at least one of them orbits a ...

Recommended for you

Black hole chokes on a swallowed star

8 hours ago

A five-year analysis of an event captured by a tiny telescope at McDonald Observatory and followed up by telescopes on the ground and in space has led astronomers to believe they witnessed a giant black hole ...

Swarm of microprobes to head for Jupiter

14 hours ago

A swarm of tiny probes each with a different sensor could be fired into the clouds of Jupiter and grab data as they fall before burning up in the gas giant planet's atmosphere. The probes would last an estimated ...

A recoiling, supermassive black hole

18 hours ago

When galaxies collide, the central supermassive black holes that reside at their cores will end up orbiting one another in a binary pair, at least according to current simulations. Einstein's general theory ...

Chandra celebrates the International Year of Light

Jan 23, 2015

The year of 2015 has been declared the International Year of Light (IYL) by the United Nations. Organizations, institutions, and individuals involved in the science and applications of light will be joining ...

Why is Andromeda coming toward us?

Jan 23, 2015

I don't want to alarm you, but there's a massive galaxy heading our way and will collide with us in a few billion years. But aren't most galaxies speeding away? Why is Andromeda on a collision course with ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.