Planet with four stars – a first for citizen science

17 October 2012

A major new discovery in planetary science has been made possible through a crowd-sourcing project developed by one of the Oxford Martin School’s programme directors.

Planet Hunters is among a suite of citizen science projects hosted through the “Zooniverse” project, which was founded by Dr Chris Lintott, Co-Director of the Oxford Martin School’s Programme on Computational Cosmology. Planet Hunters invites citizen scientists to help sieve through data from the NASA Kepler space mission. These data consist of brightness measurements, or "light curves," taken every thirty minutes for more than 150,000 stars. Users search for possible transit events - a brief dip in brightness that occurs when a planet passes in front of the star - with the goal of discovering a planet.

When two US participants spotted faint dips in light caused by a planet passing in front of its parent stars, their discovery of a planet with four stars was confirmed by a team of professional astronomers using the Keck telescopes on Mauna Kea, Hawaii.

Whilst binary stars – systems with pairs of stars – are not uncommon, out of the thousands of planets discovered outside our solar system, this is the first time a planet has been discovered to have stars orbiting stars around it. The planet, dubbed ‘PH1’ after the website, is thought to be a ‘gas giant’ slightly larger than Neptune but over six times the size of the Earth, located just under 5,000 light-years away. Quite how such a four star system remains stable enough not to tear PH1 apart is a mystery.

'It's fascinating to try and imagine what it would be like to visit a planet with four Suns in its sky, but this new world is confusing astronomers - it's not at all clear how it formed in such a busy environment,’ said Dr Chris Lintott.

Citizen science projects such as this one use mobile phone and computer technology to harness general public help to analyse complex data sets. From asking volunteers to decipher handwriting in First World War ship's logs to provide information to climate scientists and social historians, to helping characterise bat and whale calls, such crowd-sourcing projects are proving to be not only popular but productive. Other projects in the Oxford Martin School are now hoping to harness the power of citizen science projects to help them with issues like identifying biodiversity hotspots or interpreting birdsong.

More about citizen science at the Oxford Martin School

Watch Pedro Ferreira answer ‘Why do we need citizen science?’

Watch Kathy Willis discussing biodiversity and citizen science

More about Chris Lintott’s Galaxy Zoo Citizen Science project


Photo: Haven Giguere/Yale