AAS Highlights
Many of the Planet Hunters team were at the American Astronomical Society’s 218th meeting in Boston earlier this week. The team contributions to the meeting included a poster led by John Brewer on the new exoplanet candidates spotted by you and an epic review talk by Debra Fischer titled “From Hot Jupiters to Habitable Worlds.” In her talk, Debra discussed Planet Hunters showing some of our discoveries as well as mentioning the names of several Planet Hunters users.
In her talk titled “The Status of Kepler’s Search for Earth-size Planets,” Kepler team member Natalie Batalha also mentioned Planet Hunters and the Planetometer (which had already hit 3 million classifications) was shown on the big screen during her talk.
But the most fun part of the meeting was that Planet Hunters and other Zooniverse scientists and volunteers (Alice Sheppard, aka @penguingalaxy) got together to talk science, citizen science, and how to learn more about the Universe with you help!
Should you mark it as a transit?
A question that comes up regularly on Talk is whether you should mark something as a potential transit. A lot of people are apprehensive about giving a “wrong” answer. Rest assured, there’s no such thing as a wrong answer. You are classifying real data where the true answer simply isn’t known – that’s at the heart of science.
So what should you do if you’re not sure? If your instinct tells you that a feature might be a real transit, you should mark it. The reason for this is that that’s where the real information comes from. Other people will see the same data and classify it independently of you. Citizen science projects like Planethunters tap into the “Wisdom of the Crowd” effect where the decision (classifications) of a large group can be more effective than a single expert.
But for this to work, we need a diverse and independent set of classifications. So next time you worry about whether to click on something, listen to your own experience and instinct, and if in doubt, click on it. If it’s a real transit, chances are others will click on it too.
Keck Follow-up
Hello PlanetHunters! The Kepler field is finally visible and tonight, grad student John Brewer and I began observing a few of the candidates that you identified. We are operating the Keck telescope in Hawaii remotely from New Haven, CT. The weather in New Haven may not be great tonight, but it’s perfect in Hawaii – we have clear skies!
There were several steps involved in selecting the best candidates to observe tonight.
- You all did the hard first step, classifying data from Q1 to identify prospective transits.
- Stuart extracted 3500 prospective transits from the database.
- We examined all of your selections by eye – about 100 planet candidates survived (many transits per candidates).
- Yale grad student, Matt Giguere, wrote computer programs to model the light curves and to search for evidence of blended background binary stars. Visiting grad student, Thibault Sartori, has been using this code for the past several weeks to model all of the planet candidates – about half of the 100 planet candidates survived that analysis.
- John and I will analyze the spectra we collect tonight to derive stellar parameters (temperature, surface gravity and chemical composition) – this will help to better constrain the planet radius.
- Jason Rowe and Natalie Batalha from the Kepler team kindly agreed to analyze our top candidates with the Kepler data verification pipeline to help eliminate additional false positives.
It will be tough to go to the next level and confirm any of these as planets because the stars are faint. It is sure easy to understand why the Kepler team has more than 1200 planet candidates, but currently only 11 confirmed planet-hosting stars. It is a long road from planet candidate to a bonafide planet!
Introducing the Planetometer™
Introducing the new and fantastic Planetometer™ created by Planet Hunters lead developer Stuart Lynn. Here you can watch the number of classifications in real time. Additionally we’re streaming the planet candidates and the usernames of those who identified them. If you have a mac you can also make the Planetometer™ as your screensaver. Download the dmg here. As part of Chicago’s Adler Planetarium’s Spring Break at the Adler Seo Company (March 24-April 24) Planet Hunters is being featured and the Planetometer™ is being streamed live there for everyone to see.
Cheers,
~Meg and Stuart
Telescope Proposal
Hey everyone,
Yesterday myself, Meg, Chris and the rest of the Planet Hunters team where working hard to get us to the next stage of discovery with Planet Hunters. As you all know we have been really successful at finding interesting objects that the Kepler team’s automated algorithm has missed. Our first trawl through the data has netted us lots of potential planet discoveries. While this is great we really want to remove the potential from the sentence! So yesterday the team submitted a proposal to to the Keck telescope to request time to follow up the results from the site.
The Keck telescope is a wonderful instrument located 4,145 metres up, near the summit of Mauna Kea in Hawai’i. Composed of two telescopes each with a mirror 10 metres across, it is one of the best astronomical instruments in existence.
Unfortunately this means Keck, like most modern telescopes, is large, complex and therefore expensive. It cant be run by any one team or even any one country. It might be many times larger than your telescope at home but at least you get to look through that telescope whenever you want, while astronomers have to share time on Keck. Infact share is even stretching it a little, what actually happens is astronomers compete each year for time on the telescope. Unfortunately this competition doesn’t involve some kind of X-Factor public voting system (otherwise we could get all you guys to rig it for us) but rather is decided by a board of scientists who run the Keck telescope. Each year they receive a lot of requests from scientists to use their magnificent instrument but there is only enough time for a limited number of observations. The science team for Keck will independently asses each request for scientific merit, practicality and interest to decide who gets those valuable hours gathering photons.
To make matters worse pretty much every telescope, on earth or in space, has this competition at the same time each year. This means that astronomers all over the world scramble to get their proposals in and astronomy departments are full of sleep-deprived, very stressed-out people. Meg, who did the lion’s share of the work for our proposal, also had another 2 due at the same time for different telescopes! She somehow managed to get them all in and I hope is even now sleeping to recover from her ordeal. Thanks, Meg!
We have asked them for two nights worth of observing time using the HIRES instrument on Keck. During this time we point the telescope at and take spectra of our top planet candidate hosts. This will let us do two things, learn more about the host stars themselves to lets us characterise the potential planets better, but more excitingly it will let us look for the telltale wobble of the host star. If we see this it would would give us independent confirmation what we are seeing is really an exo-planet! At that point we can bin that annoying “potential” prefix and say without fear of contradiction that you, the Zooites of Planet Hunters, have discovered a new world !
We are by no means guaranteed to get the time but we all have our fingers crossed and we will let you know as soon as we do.
Q2 Data now fully online!
Hi all –
The Q2 data (chopped up into Q2.1, Q2.2 and Q2.3) are now fully online. Since these data cover a much longer time frame than just the Q1 data, we can now start looking for planets with longer periods. If you spot a single transit in a light curve that you think looks good, why not check all the other data (bot Q1 and Q2) for similar transits; it may be a long period planet.
Why is this so interesting? A planet around a star like our sun that is far enough away not to be fried by the star takes about one year to go around the star once. So you’d see one transit every year. Like our own earth. Around a dimmer star than our sun, the habitable zone is closer in, but still long. So happy hunting, especially for long period transits!
Gaps in the Data
I wanted to give a brief update on the gap question and talk a little more about what causes those gaps in the data.
You might have noticed that the gap question is no more. All of the lightcurve sections from Quarter 2 have breaks of varying sizes in them which was not the case for the Q1 data, so we removed the gap question from the interface yesterday. The gaps are caused by a few different things: Kepler went into safe mode and wasn’t taking data, the spacecraft was rotating towards the Earth, the spacecraft has executing a roll (or quarterly roll as its called) to reorient its solar panels, or the data is bad either due to a cosmic ray hit or something else.
The spacecraft rolls and safe mode tend to make of the majority of the data breaks. Kepler must rotate towards Earth to send its science data on timescales of approximately 30 days. During those monthly data downlinks Kepler must point away from the field and point its antenna towards the Earth to send the 150,000 lightcurves of data collected to the science operations center via NASA’s Deep Space Network. Every few months, the spacecraft must also reposition its solar panels toward the Sun and point Kepler’s radiator into deep space with a quarter turn, which causes an additional gap of about 1 day in the lightcurves. The reason we don’t see any gaps in the Q1 data (about 35 days) is because it encompasses one downlink of data, but since Q2 is 90 days there is both the quarterly and month rolls.
I’m off to Kitt Peak for an observing run to observe a transit in our own solar system. Dwarf planet Huamea’s moon (Nemaka) is passing in front of Haumea Friday night and I’ll be attempting to observe the drop in light caused by Nemaka on the WIYN telescope (3.5 m) while my collaborators will be observing the event from the Hale Telescope (200 inch) at Palomar Observatory.
Happy Hunting,
PS. I also wanted to say thank you for everyone’s patience and understanding while we’ve sorted out the Q2 data upload and the Talk links.They should hopefully be done late tonight early tomorrow
Looking for Gems in Talk
I wanted to talk a bit more about the Talk collections. There is a treasure trove of information sitting in all of the unique and interesting collections you are all making in Talk. We made our first list of planet candidates using the classifications you’ve all made in the classify interface (see John’s post). We want to start digging into your great Talk collections and find the interesting gems in there.
We have a visiting student from France, Thibault Sartori from École normale supérieure. One of his projects is going to be taking a look at all the great Talk collections you made. He will be looking for interesting transits, small radii-planets, and multi-planet system that may not be extracted from the classify interface. If you have a collection of interesting transits or potentially new multi-planet systems, we’d like if you can add a #phtransits (for single planet systems) and #phmulti (if you have collections of multiplanet systems) to your collections. We’ll search the Talk database for collections with these keywords and extract their entries after Sunday.
We’re also willing to feature a collection on the Talk page, so if you have something cool you want the rest of the community to see or what help with adding new objects, tweet, email, or post it on facebook and we’ll feature the collection on the front page. We can’t wait to see what’s in your collections, and we’ll keep you posted on Thibault’s progress and what we find on the blog.
Happy Hunting,
PS. I was observing in Chile at La Silla two weeks ago, and wanted to share some pictures of the telescopes. I was using the NTT the kinda of squarish telescope in the back left which has the clouds behind it
Q2 Data Release and Site Upgrades
We wanted to talk more about the changes to the site and give you all an update on the addition of Quarter 2 data. John’s already talked about the candidates page and some of the new features associated with that, so I wanted to focus on the changes specific to Q2 data release.
NASA and the Kepler team released Quarter 2 on Feb 1st and on Feb 2nd the latest results from the Kepler mission including a complete list of planet candidates and false positives for the first 2 quarters of data. You can read the paper detailing all of this here as well as the Kepler press conference site
The second data release is 90 days so we now have the first approximately 120 days of the Kepler science mission to go through. Q1 was about 35 days, we have chosen to show chunks of the lightcurve in the same size as we were for Q1. So Q2 is broken into three sections. Our aim was to have 5 days worth of overlap in each section, so that we don’t miss any transits that happen at the starts and ends of where we separated the lightcurves. We’re also uploading the Q1 data from the ~400 stars originally withheld and released on Feb 1st. We’ll keep you all posted on the progress.
We have been uploading the new data in batches to make the transition as smooth and seamless as possible. Occasionally the Talk links lag behind because we’re trying to upload as fast as you’re all going through the data. And sometimes you beat us to it
so we’ve increased how fast we’re uploading the Q2 data to keep up with your pace. We’ve appreciated all your patience during this process.
You can tell which part of the lightcurve you are looking at by the APH#. The first two numbers are quarter and section so APH22332480 is section 2 of Quarter 2. We use APH for the lightcurve sections and SPH for referring to the star itself. For the SPH numbers the first two numbers refer to what quarter the star first appeared in the public data set. so SPH21332480 first appeared is Quarter 2 Section 1.
The star source pages (like http://www.planethunters.org/sources/SPH10129795) contain all the sections of lightcurve for you to review and the x-axis is the days from the first observation, so you can look for repeat transits in other sections of the lightcurve easily. Also the downloadable CSV file now contains all the available lightcurve data. We have also updated the gap question (the first question asked) in the classify interface, so now you will now be asked the variability questions regardless of how your answer the gap question (before the variability questions were skipped if you answered yes to their being a data glitch or gap in the lightcurve)
We’ve made some changes to Talk to accommodate the Q2 data. The new planet candidates list and false positive list from the Kepler team are now identified. We’re planning in the near future of marking Planet Hunters planet candidates as well. Each lightcurve section has it’s own object page (ie http://talk.planethunters.org/objects/APH22332480). We now have group pages that gather all the available lightcurve object pages for the star (http://talk.planethunters.org/groups/SPH21332480) which you can access through the “View Star” link on any of the object pages. The “Examine Star” link will take you directly to the star’s source page.
As always we welcome feedback on the new changes, and we are listening to your comments and suggestions on Talk and in your emails. We can’t wait to see what we find in the Quarter 2 data.
Happy Hunting,
Candidate Selection
Hello there planet hunters, John here again. We know that you have been anxiously awaiting word on all of the transits you have been detecting. The first batch of stars with promising transits has been released today and I wanted to give you an overview of how we selected these particular stars out of the ones you marked.
We started with the 1.2 million classifications you made between December 15th and January 16th. Any star which had a transit marked by at least 5 people and had not previously been published was our first cut. That left us with 3533 stars.
We then had a small team of astronomers here at Yale quickly go through and rate these on a 5 point scale as likely planets and eclipsing binaries. A sort of Hot-or-Not for transits. We were now down to about 800 stars that fell into one or both of those categories.
Finally, three senior dip spotters went more carefully through this list, rating them again. Any star which was marked as either a possible planet or eclipsing binary with a score of 4 or better made it onto this first list of candidates. 90 possible planets and 42 possible eclipsing binaries!
There were many exciting transits that did not make the cut. Mostly it was because we need more data. You will notice that there are some single transits in the list, but there were just so many good ones it was hard to leave them out.
Our next step is to model these transits and weed out any more that may look promising by eye but aren’t quite as regular as they appear. This will also allow us to add radius and period information for most of the stars. Additionally, we will be including all of those stars where you identified existing planets, planet candidates, and eclipsing binaries from published works. I can already tell you that you easily found all of the published confirmed Kepler planets which were in the data.
So, head on over to the Candidates pages, or check out the two new links on your profile page which shows you any planet or eclipsing binary candidates which you marked a transit on.
Thanks for all of the hard work!
John M. Brewer
Planet Hunters 