In 2010, the Planet Hunters website began showing light curves from the Kepler mission to Citizen Scientist volunteers. This project was different from other Zooniverse projects like the successful “Galaxy Zoo” because instead of showing beautiful images, we were serving up “boring graphs” of brightness measurements for 150,000 stars. • Would people be interested in spending time sifting through these data to find changes in brightness from transiting planets? • Would humans beat out the sophisticated computer algorithms designed by NASA scientists? • Would Planet Hunter volunteers contribute unique scientific discoveries that would otherwise be undiscovered today?
We now know the answers to these questions: yes, yes and yes! In retrospect, the right question would have been: can the scientists keep up with the wave of discoveries from Planet Hunter volunteers? Barely!
Planet Hunters has been a game-changer and showcases the ability of Citizen Scientists to make important discoveries. Here are some highlights of the ways that you have changed our understanding of exoplanets: 1. Planet Hunters independently identified about 2000 of the planets found by the NASA Kepler team. 2. Excluding cases where a discovery was also made by science teams working on the Kepler data, Planet Hunters uniquely contributed 120 unique discoveries that would otherwise still be buried in the Kepler data today. For transiting planets with orbits longer than 2 years, Planet Hunters detected 50% of the planets that are known today. 3. You identified hundreds of eclipsing binary stars, and most surprising, planets orbiting outside of eclipsing binary systems! Who knew that these objects could even exist? …you found them! 4. You identified the most mysterious star in the galaxy: “Tabby’s Star,” which gained notoriety when Jason Wright at Penn State suggested that this could be the sign of an alien megastructure. We did not promote that intriguing explanation, but Tabby Boyajian gave an amazing TED talk about this discovery and has an ongoing campaign to study that star.
This scientific legacy could not have happened without the many, many hours that all of you put into this project. Your patient and persistent clicks on prospective transit events have changed our understanding of exoplanets. Thank you for your hard work! We also owe a debt of thanks to the dedicated Zooniverse team, the postdocs, grad students and undergrads who worked tirelessly on Planet Hunters!
Over the past 8 years, we became friends. We chatted through the Talk site, met each other at Kepler meetings and our most active users wrote data analysis tools and helped to guide new volunteers. Many of you were co-authors on Planet Hunter discovery papers. In 2012, Planet Hunter Kian Jek won the American Astronomical Society Chambliss prize for “achievement in astronomical research by an amateur astronomer.” In 2016, that prize was awarded to Daryll LaCourse. In 2017, we were saddened by the passing of Gerald Green, a co-author on science papers and one our most active volunteers. In May 2018, Smith College students Rebekah and Jennifer Kahn, who became interested in astronomy while volunteering as high school students, arrived at Yale to work on summer research, modeling of the Kepler-150 system.
Now, it’s time for a transition – a new beginning for Planet Hunters. There will be a new look and feel to the website, and the light curves will come from the NASA TESS mission (launched in April 2018), instead of Kepler. We need you more than ever and hope that you’ll continue with the search for transiting exoplanets and other weird things in the galaxy!