BBC Stargazing Live

We at Planet Hunters are thrilled to be part of this year’s BBC Stargazing Live  – three nights of astronomy programing featured on the BBC  hosted by Dara O Briain and Prof Brian Cox. Existing Planet Hunters will be glad to know that to celebrate we’ve put brand new data up on the site – Quarter 4 has now been added and there’s more to come. We’re keen to win the race to find whatever’s in this dataset, and so we’ve challenged the viewers of Stargazing to help us view 250,000 classifications light curves in the next 2 days.There’s a countdown on the Planet Hunters homepage, and we’ll announce what we might have found on Wednesday’s edition of Stargazing.

If you’re new to PH, let us tell you more about the project. With your help, we are looking for planets around other stars. When an extrasolar planet or exoplanet passes in front of its parent star, or transits, a dimming of the star’s light is observed. The transit depth, or decrease in the star’s brightness, is related to ratio of the planet’s radius to that of the star. For a Jupiter-­‐ sized planet (~10 Earth radii), the transit depth is ~1% of the star’s apparent brightness. For Earth-­‐sized planets, the drop in brightness is less than 0.01%.

NASA’s Kepler spacecraft monitors ~150,000 stars for transit signatures taking a measurement every 30 minutes.The Kepler light curves, the time series of brightness measurements, are complex. Many exhibit short-­‐lived variations in brightness. Such variability is difficult to characterize. Using computer algorithms, the Kepler team has detected over 2,000 potential planet candidates and 33 confirmed planetary systems. Despite the impressive success of the Kepler Team’s automated analysis, we think that computers may not recognize transit signals dominated by the natural variability of the star.

But we need your help. The Kepler team has just released the next 3 quarters of  Kepler data, nearly 270 days worth of additional  observations to the public. Chris  issued the challenge today; help us search the data for new planet transit signals over the next three days of Stargazing. Mark where you think there might be dips in star light due to passing planets. We’ll review all your classifications and look for new planet candidates and on the last night we’ll preset what we find . Help us make our goal of 250,000 classifications in 48 hours.