Classifying stars by consensus
Lewis Haley recounts the thrill of being part of a Zooniverse citizen science astronomy project that draws on input from a global network of participants
bit.ly/2UYkZWO uperWASP is an experiment in a long line of research projects with names so fantastical one might be forgiven for believing the choice of acronym precedes the name. The Wide Angle Search for Planets (WASP) scoured the whole sky (excluding the galactic plane) every night for 10 years, to find exoplanets orbiting distant stars. It turns out, taking photos of the whole sky every night captures the whole sky, every night – surprising, I know.
I was introduced to the mass of SuperWASP data while studying astrophysics with the Open University. Using this data as a guide, my team and I observed variable stars using the PIRATE telescope (another great name) on Tenerife, hunting for as much information as we could. I was hooked and I wanted more; I wanted to spend every waking moment
Sstaring at graphs that so succinctly describe how stars behave. My poor wife was only too happy to hear all about that new EW-type of contact binary with an unusually high amplitude that I had just identified… I must remember to buy her flowers.
I was delighted when the SuperWASP Variable Stars Zooniverse project went public in 2018, presenting 1.6 million objects as light curves plotted on a graph of flux against phase for the public to interpret; my wife was “thrilled”. Each point on the graphs represents the brightness of the star in a single image taken at a specific time and date. The data benefits from a high cadence and a long baseline, meaning many observations per night for many, many nights, creating dense graphs from which stellar characteristics can be identified with relative ease.
The aim of the game, on the Zooniverse project’s website, is to match the given graph to one of six categories of light profiles. There’s a handy fieldguide detailing the categories, with further details on subcategories. Some are easy to identify, some not so much; but there’s no need to panic, decisions made here are not final. The final classification is based on a consensus, with professional oversight, and you won’t get in trouble if you get it wrong.
Once a star has been classified, there’s an opportunity to discuss it. You can ask questions, make comments, or provide any more detailed information you might glean from the graph. It’s at this point you realise you are part of a wider public community – a collective of people all working towards the same goal – to understand the Universe. That’s why I do it. To be part of the scientific community, hell-bent on knowing more about everything. The discussion section is where you’ll find handy hints and links to additional resources, as well as other people with a rich knowledge on the subject.
This Zooniverse project is something you can get involved with as and when you fancy. There are no annoying deadlines; I do it in those rare spare moments. I’d be lying if I said my wife hadn’t knocked on the bathroom door more than once to check I’m Okay. Of the 1.6 million light curves, together we have classified around 750,000... Send help!