The response from BBC Stargazing viewership has been amazing! We have over 100,000 unique vistors to the Planet Hunters website since the start of the first broadcast on Monday. With volunteers participating in the UK and around the world (see where our classifications came from), we’ve completely shattered our goal of 250,000 classifications during BBC Stargazing, crossing 1 million classifications before the last broadcast even started! Well done and thank you- it would take a single person more than 2.5 years of non-stop work to match your collective effort!
With all the clicks, the science team -and their computers – have been working hard to keep up! We’ve been searching for planet candidates identified in the classifications to present for the final night of Stargazing. We have several interesting candidates that we’ve identified in the new Quarter 4 data. We still need to do careful vetting to confirm we can reject other false positives that mimic transit signals as the source for the transit-like events. But with these detections, we think we’re on the right track. One in particular looks promising and we’ve identified transits in multiple Quarters of Kepler data, with transits appearing every ~90 days. Two transits were spotted in Quarter 4 observations by Lee Threapleton and Chris Holmes, where it was noticed by the team as the Planet Hunters community was discussing the light curve on Planet Hunters Talk. The wonderful denziens of Talk, particularly Kian Jek, had already done much of the preliminary analysis. This roughly Neptune-sized (~3.6 Earth radii) planet candidate orbiting around SPH43066540 was presented by Chris live on air during the broadcast. There’s more work to be done to confirm whether these candidates are true planets – in particular, we need to talk to our friends on the Kepler team – but we’re on our way. Congratulations to you all – all that hard work is paying off.
Although we’ve hit the million classification mark for BBC Stargazing, there is more work to be done and new data to search and planets to find. We’re uploading the next three month’s worth of Kepler observations to the site in the near future. We can’t wait to find out what’s awaiting us.
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.
Computers are only good at finding what they’ve been told to look for. The human eye can easily identify deviant points and transits that may be missed by sophisticated computer algorithms. The human brain has the uncanny ability to recognize patterns and immediately pick out what is strange or unique, far beyond what we can teach machines to do. With Planet Hunters we asking you to visually screen the Kepler light curves for transits, individually reviewing 30-day segments of a star’s light curve for tell-tale transit dips signaling the possible presence of a exoplanet. Over 73,000 volunteers have made nearly 6 million classifications in the project’s first year. We’ve already netted 4 strong planet candidates (read more about those discoveries here and here) that were missed in initial reviews in other searches of the Kepler data.
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.
These Kepler observations have never before been seen by anyone on the Planet Hunters website. Most of the light curves will be flat devoid of transit signals but yet,it’s just possible that you might be the first to know that a star somewhere out there in the Milky Way has a companion, just as our Sun does. Fancy giving it a try?
~Meg, Chris and the Planet Hunters Team
PS. For comments for Stargazing Live – come to our Live Blog Post
2011-01-17 10:05PM GMT
We’ve gone past 25,000 classifications (10% of our goal) in less than an hour since Chris went on air!
2011-01-17 9:44PM GMT
over 5,600 people on the Planet Hunters website right now!
Chris is talking on the Live Chat- ask him questions here
2011-01-17 9:26PM GMT
Chris Lintott is talking about us now!
2011-01-16 9:01 PM GMT
The show’s live and even better news Quarter 4 data is live on Planet Hunters – never before seen data before – check out our new front page – help us make 250,000 classifications in 48 hours.
2011-01-16 8:24 PM GMT
Last run through for Chris – shows starts in 6 minutes…
2011-01-16 6:43 PM GMT
Chris is off doing a rehearsal of his segment. Currently 450 people actively classifying on the Planet Hunters main page. There are clear skies here at Jodrell Bank.
2011-01-16 6:24 PM GMT
Greetings Jodrell Bank and BBC Stargazing Live. Chris Lintott and I have arrived at Jodrell Bank (home of the Lovell Telescope) where BBC Stargazing Live is being filmed tonight. BBC Stargazing Live is three nights of astronomy programing featured on the BBC hosted by Dara O Briain and Professor Brian Cox. Chris will be joining the show later tonight to talk about Planet Hunters.
As we arrived at Jodrell Bank, the Sun was setting (it was chilly but we brought garcinia cambogia extract tea), and we had beautiful views of the Lovell Telescope. Here’s some images of the surroundings. Final preparations are being made for tonight, and rehearsals are underway. We’ll be updating you though out the night on our happenings so check back to this blog post regularly.
For our latest planet candidates paper, there were many volunteers who helped identify these potential transits on Talk. To thank all of them for their hard work and effort, their contributions are individually acknowledged here. A few people stood out organizing a significant follow-up effort on their own working to sort these potential candidates identified on Talk into a list of potential planet candidates. This included looking for repeat transits and performing checks to rule out potential false positives. To acknowledge their effort, the science asked Abe Hoekstra, Tom Jacobs, Kian Jek, Daryll LaCourse, and Hans Martin Schwengeler to be co-authors on the paper. I’ve asked them each write a bit about this experience and about being part of Planet Hunters.
I am from the Netherlands and am fifty years of age. In the past I used to be a teacher. Astronomy has always been a hobby of mine, I am what they call an armchair astronomer. I couldn’t pursue a career in astronomy as I am very bad at maths and physics. Early 2011 I got my first laptop and I subscribed to the NASA Newsletter. When I was reading up on exoplanets, I came across Planet Hunters. I am very glad I can make a contribution to astronomy, however small.
When I heard my name was going to be mentioned on the Planet Hunter Planet Candidates paper, I was quite surprised, excited and very honoured. I have been so busy with eclipsing binaries, variable stars, dwarf novae and checking out dozens and dozens of collections of fellow planet hunters, that I almost forgot I made some contributions with respect to finding planetary transits.I had to check the candidates on the list to see where I made those contributions. I found one candidate that I may have discovered first, shortly after I started here in February 2012, and another where I was among he first to spot a transit. I also helped in finding repeats of transit features, by checking out NASA’s Exoplanet Archive (NEA). I definitely remember two candidates I found in other planet hunters’ collections in November.Finding a transit feature and/or repeat is very exciting. It doesn’t stop there. I am among those planet hunters that regularly check stars on Sky View and the NEA. Other hunters are very experienced in doing contamination checks, determining the length and depths of transits, and also determining the period of a planet.That is what I like about Planet Hunters. There is a great sense of community and cooperation here. I hope a lot of planet hunters get a mention in the paper. A great deal of hard work has gone into finding these planet candidates, and finding your name up there is very rewarding.Let’s hope we can add a few more candidates to the list in 2013!
I am a graduate of the University of Washington with a non science degree in Business Administration and later commissioned as an officer in the U.S. Navy. Currently, I reside in Bellevue, Washington with my family and work as an employment consultant for workers with developmental disabilities going on 17 years. I have always been a treasure hunter and consider Planet Hunters a great way to find planet and other unique star treasures and learn some astrophysics through immersion along the way.
It is a great honor to be part of this planet candidate discovery paper as a Planet Hunters’ citizen scientist. Nothing occurs in a vacuum at Planet Hunters. If not for all your hard work in classifying light curves and posting your finds on Talk, most likely these planet gems would have slipped away unnoticed. You all deserve as much credit as those mentioned in the science paper. It is all about teamwork and diligent pursuit in analyzing the Kepler light curves. We are collectively demonstrating what the incredible pattern recognition of the human mind can accomplish that challenges the high powered state of the art computer algorithms and we are having fun while doing it.
I have been fascinated by the stars ever since my uncle handed me a copy of a book by H. A. Rey when I was 10 years old. It wasn’t until much later when I had children of my own that I realized that Rey also wrote the Curious George books. I guess I must have been a geek since then because the other things going on that grabbed my attention were the Apollo moon landings and the original Star Trek series.
I used to spend hours with a tiny 2-inch telescope at night looking for the Messier objects, not knowing that it was almost impossible to see them all with an aperture that small – I was hung up on M1 for a long time! It was astronomy got me hooked on science but by the time I went to college I was sidetracked by an interest in DNA and I went on to get a degree in molecular genetics at Cambridge in the UK. One of my biggest thrills while studying there was being able to use a 180-year old 12-in refractor, the Northumberland telescope (http://www.ast.cam.ac.uk/about/northumberland.telescope) during freezing winter mornings. You had to open and rotate the observatory dome using a hand-crank! At last I managed to see the Crab Nebula for the first time. It was, of course, not as impressive as the photographs in the books.
It’s been two years since the Planet Hunters was initiated and I’m so proud to be a part of its community. We’ve come quite a long way since those early days in December 2010. Back then very few amateur volunteers like ourselves really knew much about exoplanet transit photometry and we were marking every dip in flux as a transit (I guess many people still do!) and we thought that going beyond 5000 classifications was a big deal – there is even a forum topic devoted to this! I won’t mention who he is because he might be embarrassed but he is one of the co-authors and among my most prolific collaborators – he has done over 100,000 classifications!
Since 2010 then we’ve learned much about determining what is and isn’t a planet candidate. We discovered that 99% of transit events weren’t even due to planets. Most of the time they were glitches and even if they were real, they turned out to be false positives, e.g eclipsing binaries (EBs) or contamination due to background blends. I recall being so frustrated by demonstrating that so many of these were EBs that I started a secondary effort to collect what we called unlisted EBs – these were EBs not identified by Kepler’s EB expert Andrej Prsa.
But over the two years we learned how to separate a good PC from a false positive. We learned how to use a periodogram and phase plots, what were pixel centroid shifts, how to analyze TPFs, how to pull down Skyview and UKIRT images and how to model a transit light curve accurately.
Although I was named in the PH-1 discovery paper, and as exciting as that discovery is, I feel that was just happenstance. My more important contribution to the Planet Hunters initiative has been in collecting, compiling and curating the efforts of the community – In the last two years the Planet Hunters have turned up a lot of potential PCs that seemed to me to be real, and by applying all the methods and techniques mentioned above I eliminated all those that failed the tests. We were disappointed a few times when many of these discoveries were overtaken by events. I recall that the list was pared down from over 50 PCs down to 20 when the February 2012 Kepler paper was released (Batalha et al 2012). But I realized that if over 30 of our independent discoveries were real PCs, that fact alone vindicated our efforts. Slowly that list went up to beyond 30 and then reached 40 PCs. In May 2012, another paper by the Princeton team (Huang et al, 2012) took out another chunk of our PCs, but we continued to persevere and by the time the data releases of July and October came around, we had even more PCs to consider. I spent the last quarter of this year rounding these up and characterizing them.
I would not have been able to do this with the help and contribution of the community. I’ve been very privileged to work with some of the smartest and dedicated citizen scientists on this site. I tried my best to follow up on every e-mail and private message you sent me – please keep them coming!
I’m a Canadian aerospace machinist and amateur astronomer living in the Pacific Northwest. I prefer working with Kepler data to backyard stargazing as heavy clouds and rain can’t interfere with the former.
I am very pleased to see the release of the fifth Planet Hunters discovery paper and the addition of PH2b to the family of confirmed exoplanets. Every volunteer that has participated in the Planet Hunters project thus far has played an important role in the efforts that led to the identification and consolidation of this latest candidate list, which includes a stunning array of potential habitable zone prospects. It is impressively difficult to confirm that a Kepler candidate is a bona fide exoplanet rather than a false positive; thanks to the meticulous follow up work of Ji Wang and the rest of the PH Science team we can say with confidence that these 43 candidates are very likely the real deal.
It has been a privilege to work with so many talented individuals on PH Talk as these discoveries were sifted from the many thousands of highlighted light curves. The tenacity and resourcefulness of the PH volunteers can’t be understated or underestimated, and I look forward to what we will find in 2013 as the extended mission progresses. There are already new targets of interest popping up on the radar for the team to pursue, and the single/double transit candidates (some of which are mentioned in the new paper) hint at a hidden population of long period exoplanets that have yet to fully reveal themselves to us. How will our own solar system eventually fit into this widening hierarchy of possible arrangements and configurations? How common are exoplanets within the habitable zones of Sun-like stars? These questions may not be resolved quickly, but the discovery of every new candidate brings us closer to definitive answers. Experts in the field have speculated that the first true Earth analog candidate may be found this year, which will be a very exciting and historic milestone. I don’t think it is a huge stretch of the imagination to consider that with some sharp eyed luck, it may even be found by one of you!
Hans Martin Schwengeler
I’m a regular user (zoo3hans) on PH, more or less from the beginning two years ago. My name is Hans Martin Schwengeler and I live near Basel in Switzerland. I’m 54 years old, I’m married and we have two children. I’m a mathematician and work as a computer professional. I like to advance Science in general and Astronomy in particular. I did work a few years at the Astronomical Institute of the University of Basel (before it got closed because they decided to save some money…), mainly on Cepheids and the Hubble Constant (together with Prof. G.A. Tammann). Nowadays I’m very interested in exoplanets and spend every free minute on PH.
I’m pleased to hear that I’m going to be mentioned as a co-author of the PH Habitable Zone (HZ) candidates paper. My motivation to participate in the PH project is not really to “name” a planet or such a silly thing, but to advance Science in general and Astronomy in particular. Probably I’m just a curious fellow, although I’ve got named “a cold precise German” on PH Talk by someone (actually I’m Swiss).
I think we have a few very good cases of fine planet candidates collected over the last two years, a few of them even in the HZ of their host stars. Kian Jek (kinjin) has made a good list, many other PH users have also contributed a lot to our collaborative effort. I try to classify as many stars as possible, and also to comment on promising cases, or comment avoiding glitches and other bad features. To examine a promising star, it needs a lot of time. First I just look at the light curve and try to let my brain do the pattern recognition. I actually believe it might indeed be superior to computer algorithms to discriminate between real transits and just glitches or processing artifacts. In my experience it only works down to about 2.0 R_Earth planets, below this border size they cannot be detected anymore just by eye without prior detrending of the light curve. Second I do therefore download the FITS files from MAST and detrend roughly the light curve. Further inspection of the whole Q0-Q13 detrended light curve often reveals already if it might be an interesting case or not. If I suspect a regular signal (i.e. a well defined period) is present in the data, then I try a periodogram to see if the potential transit looks symmetrical, U-shaped and so on. Also important is to check the sky view. We are dealing with stars on the sky after all.A bit frustratingly often it’s just contamination by a nearby background star. Of course I post all findings to the PH Talk pages, so others can profit from the work done so far, and to get their opinion about the case.
Although I have classified over 30000 stars so far, even I select sometimes
a glitch for a transit. It’s not an easy “game”, but rather addictive I think. I also like the teamwork aspect of the PH community. It’s great to get help from the
“specialists” out there who can do contamination vector determination, Keppix series analysis, transit curve fitting and much more. I’d like to thank them all for their great help. I thank also Meg for her great effort to vet more promising exoplanet candidates. PH is a great project!
Hans Martin Schwengeler (aka zoo3hans)
A recent paper announcing 16 new candidates from Kepler data by Princeton astronomers Xu Huang, Gaspar Bakos and Joel Hartman has got some attention on Talk, as one of the candidates they report is the one we identified back during our mad rush through Stargazing Live. While that’s been clearly identified on talk for a while, we didn’t rush to write a paper on it, and a few people have asked why not given that the glory of first in print has now gone to the Princeton team.
The main reason is that for this candidate in particular, we wanted to wait until we could get plenty of follow-up data. Tom Barclay, in the last post on the blog talked through the various scenarios that lead to false positives, even when the transits themselves are real, and the only way to be sure you’re looking at a real planet is to go observing. We’ve been doing that for a selection of Planet Hunters candidates, including this one, and hope to report good news soon. In the meantime, for this candidate, we chose not to write up a separate paper until we had better evidence – there’s some circumstantial evidence that there might be some interference from a background source and we wanted to be careful. (We weren’t helped by the fact that the Kepler field is best seen in the summer…)
In such a new field as planet hunting, it’s not at all clear what we should make public early and what we should hang on to. This was one call it seems we got wrong, but we’re still looking forward to analysing our observations and seeing what’s really going on with this star. One thing we know we can do better is be faster to find interesting candidates, and if you want to help us with that you could do a lot worse than head over to a new part of the site where we’ve asking your help to review our best candidates.
We’ve had such an amazing response to our participation with BBC Stargazing, with over 1 million classifications completed before the start of the third broadcast. We’ve been truly swamped with classifications to search through (and that’s a good thing!). So what do we do with those 1,084,760+ classifications? So what’s next?
Well, we need to look for candidates. I’m working on that part. We have an algorithm to combine the results from the multiple users that classify each light curve in order to sort through and prioritize Q1 light curves for planet candidates. I’ve been using this pipeline to search for planets with orbits less than 15 days and with radii bigger than 2 Earth radii. I’m nearly done with the paper that summarizes the results from that search and hope to get the final numbers in the next week or so and submit the paper to a scientific journal. More on that to come soon. We’ve turned our focus to other Kepler quarters now. We’ve finished classifying all of Q2 light curves, thanks to your hard work. I’ve been starting to apply a modified version of my Q1 search pipeline to Q2. I’m working on improving it and optimizing it for the Q2 light curves, and applying it to the completed light curves from Q4 and Q3 as well. Additionally we’re scouring Talk for new planet candidates and interesting light curves people are discussing, and adding those to our list of interesting objects.
But our job isn’t finished yet. Just seeing a planet transit-like signal in the light curve, isn’t enough to say that it’s a planet and not something else mimicking it. The largest source of false positives for Kepler light curves is faint background eclipsing binaries that are blended with our target star. An eclipsing binary is a double star system where one of the star transits in front of the other as viewed from Earth. If the stars are well separated, you’ll see a characteristic double dip light curve with an alternating pattern of small dip/big dip. When the star transits in front of it’s companion, you see the big drop from the transiting star blocking out the light from it’s companion, and it when it goes behind it’s companion its own starlight is blocked out so you see the smaller dip (or secondary eclipse). Planets aren’t very bright in the optical wavelengths that Kepler is sensitive to. The light observed overwhelming comes from the star, which is why we don’t typically see a secondary eclipse in the Kepler light curves for transiting planets. So if we see that the repeating transit depths for a planet candidate are of different depths, that’s a good indicator the light curve is probably due to an eclipsing binary. But if the eclipsing binary is faint and its light is blended with that of another star, we might not see the secondary eclipse at all. So we still have to do more work to rule out this possibility.
We have a few other checks that we can do such as looking at the position of the brightest pixel for that star on Kepler’s CCDs during and after the suspected planet transit. If that position shifts that tells us we’re likely seeing a blended eclipsing binary. One more test is to get follow-up observations with other telescopes to try and look closer around the target star we think has a planet. Kepler has blurry eyes compared to bigger ground-based telescopes that have adaptive optics systems which can zoom in closer around the Kepler target star. We can use those observations to look and see if we see a companion orbiting or a faint star that is the source of the transits.
We can also try and get radial velocity measurements for the star and measured the wobble induced by the gravitational pull of the orbiting companion. How big the wobble is, tells us the mass of the orbiting body, which would tell us for certain whether the transit is from a planet or orbiting star. But most of the Kepler stars are too faint and the planet candidates are too small to provide a big enough radial velocity signal we can measure from even the best telescopes in the world. Currently the precision is a few m/s for these radial velocity measurements, and something the mass of the Earth orbiting the Sun would cause a wobble of a few cm/s which would be undetectable. So most of the Kepler and Planet Hunters planet candidates will not be confirmed with radial velocity observations but we can still try for those brightest candidate host stars.
We’re working hard on finding planet candidates and vetting the ones we have including our Stargazing planet candidate. Observing proposals to apply for time on the largest telescopes in the world, the 10-m Keck telescopes and 8-m Gemini Telescopes, are due in the next month or so. We’ll be applying for time to take follow-up our top planet candidates. More to news on all these efforts to follow soon.
While we’re working on this, there is lots more light curves that need to be viewed by human eyeballs, so keep the clicks coming, so we can find even more new and interesting planets.