Category Archives: CitizenScience

SuperWASP Variable Stars – Update

The following is an update from the SuperWASP Vairable Stars research team. Enjoy!

Welcome to the Spring 2020 update! In this blog, we will be sharing some updates and discoveries from the SuperWASP Variable Stars project.

What are we aiming to do?

We are trying to discover the weirdest variable stars!

Stars are the building blocks of the Universe, and finding out more about them is a cornerstone of astrophysics. Variable stars (stars which change in brightness) are incredibly important to learning more about the Universe, because their periodic changes allow us to probe the underlying physics of the stars themselves.

We have asked citizen scientists to classify variable stars based on their photometric light curves (the amount of light over time), which helps us to determine what type of variable star we’re observing. Classifying these stars serves two purposes: firstly to create large catalogues of stars of a similar type which allows us to determine characteristics of the population; and secondly, to identify rare objects displaying unusual behaviour, which can offer unique insights into stellar structure and evolution.

We have 1.6 million variable stars detected by the SuperWASP telescope to classify, and we need your help! By getting involved, we can build up a better idea of what types of stars are in the night sky.

What have we discovered so far?

We’ve done some initial analysis on the first 300,000 classifications to get a breakdown of how many of each type of star is in our dataset.

So far it looks like there’s a lot of junk light curves in the dataset, which we expected. The programme written to detect periods in variable stars often picks up exactly a day or a lunar month, which it mistakes for a real period. Importantly though, you’ve classified a huge number of real and exciting light curves!

We’re especially excited to do some digging into what the “unknown” light curves are… are there new discoveries hidden in there? Once we’ve completed the next batch of classifications, we’ll do some more to see whether the breakdown of types of stars changes.

An exciting discovery…

In late 2018, while building this Zooniverse project, we came across an unusual star. This Northern hemisphere object, TYC-3251-903-1, is a relatively bright object (V=11.3) which has previously not been identified as a binary system. Although the light curve is characteristic of an eclipsing contact binary star, the period is ~42 days, notably longer than the characteristic contact binary period of less than 1 day.

Spurred on by this discovery, we identified a further 16 candidate near-contact red giant eclipsing binaries through searches of archival data. We were excited to find that citizen scientists had also discovered 10 more candidates through this project!

Figure 1: Artist’s impression of a contact binary star [Mark A. Garlick] Over the past 18 months, we’ve carried out an observing campaign of these 27 candidate binaries using telescopes from across the world. We have taken multi-colour photometry using The Open University’s own PIRATE telescope, and the Las Cumbres Observatory robotic telescopes, and spectroscopy of Northern candidates with the Liverpool Telescope, and Southern candidates using SALT. We’ve also spent two weeks in South Africa on the 74-inch telescope to take further spectroscopy.

Of the 10 candidate binaries discovered by citizen scientists, we were happy to be able to take spectroscopic observations for 8 whilst in South Africa, and we have confirmed that at least 2 are, in fact, binaries! Thank you citizen scientists!

Why is this discovery important?

Figure 2: V838 Mon and its light echo [ESA/NASA]

The majority of contact or near-contact binaries consist of small (K/M dwarf) stars in close orbits with periods of less than 1 day. But for stars in a binary in a contact binary to have such long periods requires both the stars to be giant. This is a previously unknown configuration…

Interestingly, a newly identified type of stellar explosion, known as a red nova, is thought to be caused by the merger of a giant binary system, just like the ones we’ve discovered.

Red novae are characterised by a red colour, a slow expansion rate, and a lower luminosity than supernovae. Very little is known about red novae, and only one has been observed pre-nova, V1309 Sco, and that was only discovered through archival data. A famous example of a possible red nova is the 2002 outburst in V838 Mon. Astronomers believe that this was likely to have been a red nova caused by a binary star merger, forming the largest known star for a short period of time after the explosion.

So, by studying these near-contact red giant eclipsing binaries, we have an unrivalled opportunity to identify and understand binary star mergers before the merger event itself, and advance our understanding of red novae.

What changes have we made?

Since the SuperWASP Variable Stars Zooniverse project started, we’ve made a few changes to make the project more enjoyable. We’ve reduced the number of classifications needed to retire a target, and we’ve also reduced the number of classifications of “junk” light curves needed to retire it. This means you should see more interesting, real, light curves.

We’ve also started a Twitter account, where we’ll be sharing updates about the project, the weird and wacky light curves you find, and getting involved in citizen science and astronomy communities. You can follow us here: www.twitter.com/SuperWASP_stars

What’s next?

We still have thousands of stars to classify, so we need your help!

Once we have more classifications, we will be beginning to turn the results into a publicly available, searchable website, a bit like the ASAS-SN Catalogue of Variable Stars (https://asas-sn.osu.edu/variables). Work on this is likely to begin towards the end of 2020, but we’ll keep you updated.

We’re also working on a paper on the near-contact red giant binary stars, which will include some of the discoveries by citizen scientists. Expect that towards the end of 2020, too.

Otherwise, watch this space for more discoveries and updates!

We would like to thank the thousands of citizen scientists who have put time into this Zooniverse project. If you ever have any questions or suggestions, please get in touch.

Heidi & the SuperWASP Variable Stars team.

Fulfilling Service Hour Requirements through Zooniverse

Over the past week a number of students and organizations have reached out to us to see if Zooniverse participation can fulfill volunteering/service hour requirements for graduation, scholarships, etc.

The short answer is — Yes! Many organizations welcome and encourage Zooniverse participation as a way to fulfill service hour requirements. 

We recommend that organizations place at the forefront what students/participants get out of these experiences beyond contributing time and classifications. Rather than creating busy work, we favor a model where participants take time to reflect on how their efforts (and the community’s collective efforts) are contributing to our understanding of our world and the broader universe. 

Here is one approach for constructing a productive and rewarding volunteer experience for your organization:

Step 1: Share this opportunity with your Organization

Email your organization to see if participation in Zooniverse can be used to fulfill volunteering or other participation requirements. Share this blog post with them so they understand what you would be doing and how you’ll ‘document’ your participation (see Step 8 below). 

Step 2: Register at Zooniverse.org

Create a Zooniverse account by clicking ‘Register’ in the upper-right of the Zooniverse.org homepage (only a name and email are required).

Registering is not required to participate in Zooniverse. But it is useful in this case in order to provide a record of participation.

Step 3: Zooniverse background info

Watch this brief animation and video for background/context about the Zooniverse, the world’s largest platform for people-powered research, with 100 active projects and 2 million people around the world participating. Every Zooniverse project is led by a different research team, spanning a wide range of subjects that include: identifying planets around distant stars (PlanetHunters.org), studying the impact of climate change on animals (SnapshotSafari.org) and plants (FloatingForests.org), tracking resistance to antibiotics (Bash the Bug), transcribing handwritten documents (antislaverymanuscripts.org), and more. The collective efforts of Zooniverse projects have resulted in over 200 research publications to date.

Step 4: Choose your project(s)

Choose from the full list of ~100 active Zooniverse projects (see zooniverse.org/projects) or choose from the curated lists of projects below that tend to work well with different age groups, as selected by the Zooniverse team: 

Step 5: Learn a bit about the project before diving in

Read the information on the project’s ‘About’ pages (‘Research’, ‘The Team’, ‘Results’, & ‘Education’) to learn more about the research and the team running the project.  For example: https://www.zooniverse.org/projects/mrniaboc/bash-the-bug/about

Step 6: Participate! 

Click on the ‘Classify’ tab of your chosen project to get started.  A brief tutorial provides instructions and guidance. For example: https://www.zooniverse.org/projects/mrniaboc/bash-the-bug/classify

Step 7: Reflection and Extension

Consider these Reflection Questions, or other similar questions.  The questions explore the ‘why’ behind this experience. Why do the researchers need your help? How might the results help science? Are you interested in participating in other projects of this type, and why or why not?

For Organizations: Consider sending these via a Google Form or other survey tool for participants to submit responses to these questions. Note: before using the example form above, make a copy of the Google form and send the survey from your own account to make sure you can access the responses.

Extension opportunities:

Each project has a  ‘Talk’ discussion forum associated with it (e.g., https://www.zooniverse.org/projects/mrniaboc/bash-the-bug/talk). This is where the researchers and participants from around the world chat with each other — asking questions about the science, weird things people see while classifying, new discoveries, & more. First, explore the discussion threads and check out some of the questions other people have asked. If you’re feeling comfortable, ask the researchers a question about the science, being a scientist, etc. You might start with a question you asked as part of the ‘Reflection Questions’ activity above. The researchers are keen to hear your questions and engage with you. Check back later to see the response, or watch for Talk email notifications, if you’ve enabled them.

Post-experience (a lifetime of engagement): Check out other Zooniverse projects and check out NASA’s Citizen Science project list and SciStarter for other citizen science opportunities. And please do share about citizen science with family and friends (peer networks make a BIG difference in what people try).

Step 8: Document your participation to fulfill your requirements

Once signed in at Zooniverse.org, you’ll see your display name and your total classification count. (If you hover over the doughnut-ribbon in the center top of the page, you’ll see the classification counts for each specific project you’ve participated in.)

Please note that there is no built-in time-tracker within Zooniverse. However, some organizations allow participants to use the number of classifications they’ve contributed as a proxy for time spent on the site. On average, a person contributes 20-75 classifications/hour on most projects (this ranges widely depending on the difficulty of the tasks, the number of tasks for a given classification, etc.). 

For example, if someone has done 100 classifications, you can estimate that they’ve spent ~2 hours classifying on Zooniverse; e.g., 2 hours x 50 classifications / hour = 100 classifications. The Organization should add ~45 minutes to this time estimate for the time it takes to carry out the additional ‘meta’ elements of the experience outlined above.  

Please note – because we are a small organization, we are not able to sign individual’s ‘certificates of completion’ or other records of that type for volunteer hours.

For Organizations: Consider using a Google Form or other survey instrument for participants to submit their classification count and a screenshot of their Zooniverse.org page. Note: make a copy of the Google form and send it from your account so you can access the responses.

Other Information

If you need to reference a 501(c)(3): 

While Chicago’s Adler Planetarium, one of the hosts of the Zooniverse web development team, is a 501(c)(3), the Zooniverse is not. Organizations that need to link explicitly to a 501(c)(3) for their volunteering efforts use the Adler Planetarium as the reference.  Documentation of the Adler Planetarium’s 501(c)(3) status is provided here.

Future Work:

We recognize it would be helpful to have an easier way to share participation information with organizations for these purposes (though this will need to be done in a very thoughtful way). Please note that because we are a grant-funded web development team, enhancements of this type take time to design, build and implement. If you or your organization have suggestions for how best to share this information, or are interested in helping to support this effort via collaborative grant-writing or otherwise, please let us know.

THANK YOU!

As always, please don’t hesitate to reach out to contact@zooniverse.org if you have any questions or suggestions. 

Chicago Earth Fest celebrations

The Chicago Zooniverse team had a great time celebrating Earth Day with members of the community at the Adler Planetarium and Chicago Botanic Garden.

At the Adler Planetarium’s EarthFest celebration on Saturday, April 13, guests were able to participate in an in-real-life version of Floating Forests, tracing areas of kelp from a satellite image onto tracing paper to see how a consensus result might be reached in the online version. Online at https://www.zooniverse.org/projects/zooniverse/floating-forests, you’ll be able to do this same activity, helping researchers learn how Giant Kelp forests change over time.

The next day at the Chicago Botanic Garden’s UnEarth Science Festival, visitors learned about the parts of a plant though a matching activity that segued into Rainforest Flowers, a Zooniverse project helping researchers at the Field Museum in Chicago to create a database of images of plants from the tropical forests of Central and South America.

We love meeting the community! If you missed us this time, keep your eye on this blog for our next event.

CELEBRATING CITIZEN SCIENCE DAY 2019, PT. 5

This coming Saturday 13th April is Citizen Science Day, an ‘annual event to celebrate and promote all things citizen science’. Here at the Zooniverse, one of our team members will be posting each day this week to share with you their favourite Zooniverse projects. Today’s post is from Grant Miller, project manager of the Zooniverse team at the University of Oxford.

Having been at the Zooniverse for almost six years and helped over one hundred research teams launch their project on the Zooniverse platform I find it very difficult to choose just one of them as my favourtie. However, unlike Helen did on Tuesday, I’m going to give it a try 😛

For me it’s got to be the very first project that  was pitched to me on my first  day of the job back in 2013 – Penguin Watch! Over the last decade the lead researcher Tom Hart and his team have been travelling to the Southern Ocean and Antarctica to place time-lapse cameras looking at penguin nests. They now collect so many images each year the cannot do their science without the help of the Zooniverse crowd. This projecy perfectly demonstrates the key elements which go into making a truly great citizen science project:

  1. It has a clear and relatable research goal: Help count penguins so we can understand how over-fishing and climate change is affecting their populations, and then use that information to influence policy makers.
  2. It has an extremely simple task that for now can only be done accurate by human eyes: Click on the penguins in the image. It’s so simple we have 4-year-old children helping their parents do it!
  3. It has an amazing and engaged research team and volunteer community: Even though they are a very small team the scientists take plenty of time to communicate with their volunteer community via the Talk area of the project, newsletters, and social  media channels. There is also a fantastic core group of volunteer moderators who put in so much effort to make sure the project is running as well as it should.

Half a million king penguins at St Andrews Bay, South Georgia.

In addition to all of this I was lucky enough to join them on one of their Antarctic expeditions last year, as they went down to maintain their time-lapse cameras and collect the data that goes into Penguin Watch. You can see my video diary (which I’m posting once per day on the run up to World Penguin Day on the 25th April) at daily.zooniverse.org.

Get involved in Penguin Watch today at www.penguinwatch.org.

Celebrating Citizen Science Day 2019, PT.3

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This coming Saturday 13th April is Citizen Science Day, an ‘annual event to celebrate and promote all things citizen science’. Here at the Zooniverse, one of our team members will be posting each day this week to share with you their favourite Zooniverse projects. Today’s post is from Laura Trouille, co-PI for Zooniverse and VP of Citizen Science at the Adler Planetarium in Chicago.

To follow on Sam’s Monday post kicking off this series and her mention of the diversity of approaches and models for citizen science, I thought it would be fun and helpful to highlight Hawk Talk, a project co-created by citizen scientists and researchers from the Cornell Lab of Ornithology. 

During the summer of 2018, a group of volunteers spent weeks observing the Red-tailed Hawk cam, brainstorming questions about what they were seeing, and ultimately voting on a question to investigate:

Do hawks use different kinds of calls in different situations at the nest?

Previous researchers have documented Red-tailed Hawk vocalizations, but have been mostly limited to what they can hear on the ground or when briefly checking a nest. The 24/7 Red-tailed Hawk cam gives the community the chance to document vocalizations right at the nest without disturbing the birds!

Join them at Hawk Talk for this first round of clips in which you will look at the first week of footage after the nestlings start to hatch.

We also invite you to learn more about the Bird Cams Lab, the larger project that Hawk Talk is a part of. Click here to help test new activities for co-created research investigations.

Almost every day, the Hawk Talk team posts in the project’s announcement banner. Sometimes they direct you to a specific clip to help figure out what is going on. Other times they let you know about exciting news happening on the live Red-tailed Hawks cam.

The team also posts the number of classifications received on the previous day and encourages continued participation. Help them increase the daily number of classification from ~200/day to more!

The greater the participation, the more quickly the citizen scientists and researchers can use these data to answer their question. This is a wonderful example of citizen scientists engaged in all steps of the research process. Join the Hawk Talk community and help make it a success!

Go straight to Hawk Talk or to the Zooniverse portal for Bird Cams Lab, where you can find both Hawk Talk and the Cornell Lab of Ornithology’s other project, Battling Birds.

Thank you!

 

Join us at Earth Fest!

The Zooniverse is going on the road!

To celebrate Earth Day 2019, members of the Zooniverse team will be at two events in Chicago the weekend of April 13 and 14.

First, visit us at the Adler Planetarium’s Earthfest on Saturday, April 13. Participate in a real-life version of our Floating Forests project, pick up some cool Zooniverse swag, and talk to members of the Zooniverse team about their work. The event is free with Adler admission and we’ll be there between 10 am and 4 pm.

If you can’t make it to the Adler, join us at the Chicago Botanic Garden for the Unearth Science Festival on Sunday April 14. There, we’ll be talking about all the fantastic Zooniverse projects you can contribute to online or via our app, as well as taking an in-depth look at the anatomy of flowers via the Rainforest Flowers project.

Hope to meet you there!

 

Celebrating Citizen Science Day 2019, pt. 1

To celebrate Citizen Science Day 2019, this coming Saturday 13th April, a different member of the Zooniverse team will be posting each day this week to share with you some of our all-time favourite Zooniverse projects. First off in the series is our Digital Humanities Lead, Dr. Samantha Blickhan.

From CitizenScience.org: “Citizen Science Day is an annual event to celebrate and promote all things citizen science: amazing discoveries, incredible volunteers, hardworking practitioners, inspiring projects, and anything else citizen science-related!”

Here at Zooniverse, we’re excited to participate by highlighting a series of projects that we enjoy. I want to kick things off by showing off a current project that does a great job illustrating one of my favorite things about this type of research: its ability to cross typical academic or discipline-specific boundaries.

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Reading Nature’s Library is a transcription project, launched in February 2018, that was created by a team at Manchester Museum. The project invites volunteers to help transcribe labels for the museum’s collections, which include everything from Archery to Numismatics to Zoology, so this project has something for everyone! In the 13 months since their project launched, a community of 2,669 registered Zooniverse volunteers have completed over 9,283(!) subjects.

Beyond the wide-ranging contents of their dataset, this project is a great way to show how projects can affect a range of disciplines. The results of this project could be used for research in a range of disciplines within the sciences (as varied as their collections), not to mention studies of history, archives, and collections management. Furthermore, large amounts of transcribed text can be a useful tool for helping to train machine learning models for Handwritten Text Recognition.

Today’s project selection also raises a good point about terminology and models for participatory research. Although this week we are celebrating ‘Citizen Science Day’, not all projects fit into the same ‘Citizen Science’ model, and the use of ‘citizen’ is not intended in a narrow, geographic sense. As we celebrate the efforts by project teams and their communities of volunteers, we also want to acknowledge the work being done to illuminate these differences and work to develop models for inclusivity and sustainability. The following article great place to start if you’re interested in learning more:

Eitzel, MV et al. (2017) Citizen Science Terminology Matters: Exploring Key Terms: https://theoryandpractice.citizenscienceassociation.org/articles/10.5334/cstp.96/

28 New Planet Candidates Discovered on Exoplanet Explorers

The team behind the Exoplanet Explorers project has just published a Research Note of the American Astronomical Society announcing the discovery of 28 new exoplanet candidates uncovered by Zooniverse volunteers taking part in the project.

Nine of these candidates are most likely rocky planets, with the rest being gaseous. The sizes of these potential exoplanets range from two thirds the size of Earth to twice the size of Neptune!

This figure shows the transit dips for all 28 exoplanet candidates. Zink et al., 2019

You can find out more about these exoplanet candidates in the actual research note at https://iopscience.iop.org/article/10.3847/2515-5172/ab0a02, and in this blog post by the Exoplanet Explorers research team http://www.jonzink.com/blogEE.html.

Finally, both the Exoplanet Explorers and Zooniverse teams would like to extend their deep gratitude to all the volunteers who took part in the project and made these amazing discoveries possible.

Exoplanet Explorers Discoveries – A Small Planet in the Habitable Zone

This post is by Adina Feinstein. Adina is a graduate student at the University of Chicago. Her work focuses on detecting and characterizing exoplanets. Adina became involved with the Exoplanet Explorers project through her mentor, Joshua Schlieder, at NASA Goddard through their summer research program.

Let me tell you about the newly discovered system – K2-288 – uncovered by volunteers on Exoplanet Explorers.

K2-288 has two low-mass M dwarf stars: a primary (K2-288A) which is roughly half the size of the Sun and a secondary (K2-288B) which is roughly one-third the size of the Sun. The capital lettering denotes a star in the planet-naming world. Already this system is shaping up to be pretty cool. The one planet in this system, K2-288Bb, hosts the smaller, secondary star. K2-288Bb orbits on a 31.3 day period, which isn’t very long compared to Earth, but this period places the planet in the habitable zone of its host star. The habitable zone is defined as the region where liquid water could exist on the planet’s surface. K2-288Bb has an equilibrium temperature -47°C, colder than the equilibrium temperature of Earth. It is approximately 1.9 times the radius of Earth, which places it in a region of planet radius space where we believe planets transition to volatile-rich sub-Neptunes, rather than being potentially habitable super-Earth. Planets of this size are rare, with only about a handful known to-date.

Artist’s rendering of the K2-288 system.

The story of the discovery of this system is an interesting one. When two of the reaction wheels on the Kepler spacecraft failed, the mission team re-oriented the spacecraft to allow observations to continue to happen. The re-orientation caused slight variations in the shape of the telescope and temperature of the instruments on board. As a consequence, the beginning of each observing campaign experienced extreme systematic errors and initially, when searching for exoplanet transits, we “threw out” or ignored the first days of observing. Then, when we were searching the data by-eye for new planet candidates, we came across this system and only saw 2 transits. In order for follow-up observations to proceed, we need a minimum of 3 transits, so we put this system on the back-burner. The light curve (the amount of light we see from a star over time) with the transits is shown below.

Later, we learned how to model and correct for the systematic errors at the beginning of each observing run and re-processed all of the data. Instead of searching it all by-eye again, as we had done initially, we outsourced it to Exoplanet Explorers and citizen scientists, who identified this system with three transit signals. The volunteers started a discussion thread about this planet because given initial stellar parameters, this planet would be around the same size and temperature as Earth. This caught our attention. As it turns out, there was an additional transit at the beginning of the observing run that we missed when we threw out this data! Makennah Bristow, a fellow intern of mine at NASA Goddard, identified the system again independently. With now three transits and a relatively long orbital period of 31.3 days, we pushed to begin the observational follow-up needed to confirm this planet was real.

First, we obtained spectra, or a unique chemical fingerprint of the star. This allowed us to place better constraints on the parameters of the star, such as mass, radius, temperature, and brightness. While obtaining spectra from the Keck Observatory, we noticed a potential companion star. We conducted adaptive optics observations to see if the companion was bound to the star or a background source. Most stars in the Milky Way are born in pairs, so it was not too surprising that this system was no different. After identifying a fainter companion, we made extra sure the signal was due to a real planet and not the companion; we convinced ourselves this was the case.

Finally, we had to determine which star the planet was orbiting. We obtained an additional transit using the Spitzer spacecraft. Using both the Kepler and Spitzer transits, we derived planet parameters for both when the planet orbits the primary and the secondary. The planet radius derived from both light curves was most consistent when the host star was the secondary. Additionally, we derived the stellar density from the observed planet transit and this better correlated to the smaller secondary star. To round it all off, we calculated the probability of the signal being a false positive (i.e. not a planet signal) when the planet orbits the secondary and it resulted in a false positive probability of roughly 10e-9, which indicates it most likely is a real signal.

The role of citizen scientists in this discovery was critical, which is why some of the key Zooniverse volunteers are included as co-authors on this publication. K2-288 was observed in K2 Campaign 4, which ran from April to September back in 2015. We scientists initially missed this system and it’s likely that even though we learned how to better model and remove spacecraft systematics, it would have taken years for us to go back into older data and find this system. Citizen scientists have shown us that even though there is so much new data coming out, especially with the launch of the Transiting Exoplanet Survey Satellite, the older data is still a treasure trove of new discoveries. Thank you to all of the Exoplanet volunteers who made this discovery possible and continue your great work!

The paper written by the team is available here. It should be open to all very shortly.

Exoplanet Explorers Discoveries – A Sixth Planet in the K2-138 System

This is the first of two guest posts from the Exoplanet Explorers research team announcing two new planets discovered by their Zooniverse volunteers. This post was written by Jessie Christiansen.

Hello citizen scientists! We are here at the 233rd meeting of the American Astronomical Society, the biggest astronomy meeting in the US of the year (around 3000 astronomers, depending on how many attendees are ultimately affected by the government shutdown). I’m excited to share that on Monday morning, we are making a couple of new exoplanet announcements as a result of your work here on Zooniverse, using the Exoplanet Explorers project!

Last year at the same meeting, we announced the discovery of K2-138. This was a system of five small planets around a K star (an orange dwarf star). The planets all have very short orbital periods (from 2.5 to 12.8 days! Recall that in our solar system the shortest period planet is Mercury, with a period of ~88 days) that form an unbroken chain of near-resonances. These resonances offer tantalizing clues as to how this system formed, a question we are still trying to answer for exoplanet systems in general. The resonances also beg the question – how far could the chain continue? This was the longest unbroken chain of near first-order resonances which had been found (by anyone, let alone citizen scientists!).

At the time, we had hints of a sixth planet in the system. In the original data analysed by citizen scientists, there were two anomalous events that could not be accounted for by the five known planets – events that must have been caused by at least one, if not more, additional planets. If they were both due to a single additional planet, then we could predict when the next event caused by that planet would happen – and we did. We were awarded time on the NASA Spitzer Space Telescope at the predicted time, and BOOM. There it was. A third event, shown below, confirming that the two previous events were indeed caused by the same planet, a planet for which we now knew the size and period.

So, without further ado, I’d like to introduce K2-138 g! It is a planet just a little bit smaller than Neptune (which means it is slightly larger than the other five planets in the system, which are all between the size of Earth and Neptune). It has a period of about 42 days, which means it’s pretty warm (400 degrees K) and therefore not habitable. Also, very interestingly, it is not on the resonant chain – it’s significantly further out than the next planet in the chain would be. In fact, it’s far enough out that there is a noticeable gap – a gap that is big enough to hide more planets on the chain. If these planets exist, they don’t seem to be transiting, but that doesn’t mean they couldn’t be detected in other ways, including by measuring the effect of their presence on the other planets that do transit. The planet is being published in a forthcoming paper that will be led by Dr Kevin Hardegree-Ullman, a postdoctoral research fellow at Caltech/IPAC.

In the meantime, astronomers are still studying the previously identified planets, in particular to try to measure their masses. Having tightly packed systems that are near resonance like K2-138 provides a fantastic test-bed for examining all sorts of planet formation and migration theories, so we are excited to see what will come from this amazing system discovered by citizen scientists on Zooniverse in years to come!

We are also announcing a second new exoplanet system discovered by Exoplanet Explorers, but I will let Adina Feinstein, the lead author of that paper, introduce you to that exciting discovery.