2nd Planet Hunters Paper Submitted
Way back in January I blogged about our announcement of two new candidates, confidently predicting that the paper would be out in the next few days. That didn’t happen for all sorts of reasons, but it’s now submitted to the Astronomical Journal. Rather than wait until we get the referee’s seal of approval (or a lot of criticism!), we’ve made the paper public via the arXiv – you can read it here.
As the picture on the blog post shows, five volunteers are co-authors, many more are thanked in the paper, and there’s a link to the authors page to give credit to all our volunteers for taking part. In the month or so that we’ve had since the conference, we’ve done some more work to pin down the behaviour of these systems. The first exciting new discovery was the length of time between transits was changing slightly for KIC4552729. These transit timing variations, or TTVs, suggest that there’s something else there, another body whose gravity is affecting the orbit of the planet candidate whose transits we do detect. We need more data to work out exactly what’s going on, but the immediate implication is that it’s more likely that our planet candidate is real, as it’s harder to create a three-body system using interference from background eclipsing binaries.
We also – mostly for fun – worked out whether the two planets that Planet Hunters had uncovered could be in the habitable zone of their star, that thin sliver of space where liquid water, and hence life, might be able to survive on the surface of a planet. Now, both of ours are almost certainly too large to be anything but gaseous, and one has to make a planet’s worth of assumptions about things like its albedo (how much light is reflected and how much absorbed by the atmosphere) and its atmosphere. Nonetheless, the encouraging thing is that both of our candidates seem to lie in the habitable zone of their star system, making them interesting targets.
As if that wasn’t enough for one day, also on the arXiv and submitted to the journal is the latest Kepler paper announcing new candidates. They include a section on Planet Hunters, and announce another handful of independent discoveries where we found candidates they’d already uncovered. More on that – including a list of Planet Hunters involved in those discoveries – in the next few days.