Synopsis: My team announced the discovery of “The most mysterious star in our Galaxy”, KIC 8462852 in the fall of 2015. With your help we can secure the telescope time necessary to solve the mystery. Here is the quick summary of the current situation.
The star KIC 8462852 (also known as Tabby’s Star, or the WTF star for ‘Where’s the Flux?’) was observed along with over 150,000 other stars by NASA’s Kepler space telescope. The Kepler telescope measured the variations of starlight over a period of time, what astronomers call a light curve. The main objective of the Kepler mission was to find planets. It did this by detecting the periodic dimming made from a planet moving in front of a star, and hence blocking out a tiny bit of starlight. The online citizen science group Planet Hunters was established so that volunteers could help classify light curves from the Kepler mission and search for such planets.
As Planet Hunter volunteers were sifting through Kepler data, they came across the light curve for KIC 8462852, a star that showed peculiar dips in its flux (brightness) over time which defied classification. You see, most of the time that the star has nothing going on -- its brightness was constant. But then it lost a fifth of its total flux, then nothing again, and then it had a huge collection of dips of varying shapes and depths. Figure 1 and Figure 2 are two graphs showing the star’s Kepler light curve.
In both graphs, the x-axis label “Kepler day” means days since Kepler launched. The graph in Figure 1 shows the full 4 year interval of Kepler data. It shows that the star’s flux, or brightness, is remarkably constant most of the time (seen here as the y-axis variable “relative flux” being equal to 1). However, there are two large dipping features (around day 800 and day 1500) as well as about a dozen small dips throughout the light curve (barely visible at this scale).
Figure 2 shows a zoomed-in portion of what happened in the last 3 months. There is a huge complex of dips with varying depth, duration, and shape that occur during this time.
For what remained inexplicable in conversations among the Planet Hunter volunteers who spotted the star, they reached out to us, the science team, about what could cause these strange observations. We then spent several years learning about the system testing different hypothesis on what was causing the dips.
Long story short, the discovery paper presented a long list of natural scenarios that could possibly explain the star’s observations. Such things included presence of multiple stellar companions, planets, planets with rings, dust clouds of varying origin, asteroid belts, and comets. (For those of you that hesitate to dive straight into astrophysics papers, we recommend checking out this blog compiled by science enthusiast Paul Carr, which contains summary of the facts in non-technical terms, as well as a series of posts that track the development of the KIC 8462852 investigation).
Given the observational constraints, the discovery paper concluded that the best natural explanation was that a swarm of comets passing in from of the star and blocking the star’s light. Then, the Ĝ (pronounced “G-hat”) SETI program proposed an alternate explanation invoking artificially made alien megastructures passing in from of the star and blocking light. At this point in time, the object caught the media’s attention and things started happening fast, triggering a huge response from the scientific community to jump in and figure out what was happening. Today, there is still no widely accepted theory to what is behind this star’s strange behavior.
** For background on how the story unfolded, see the TED2016 talk **
**Select media coverage**
- The Atlantic, and another recent update here
- The Late Show with Stephen Colbert
- SciShow with Hank Green
- Major news network(s) with Michio Kaku (here and here)
- The Edge
- SNL Weekend Update
- Also covered by Al Jazeera, CBS, CNET, CNN, Discover Magazine, Discovery News, Forbes, FOX, Gizmodo, Huffington Post, IFLScience, New Scientist, NPR, PBS, Popular Mechanics, Popular Science, Scientific American, Sky and Telescope, The Science Channel, The Slate, USA Today, The Verge, The Washington Post, Wired
What actions need to be taken?
The star was discovered with data from the Kepler space telescope, but Kepler has moved on to a different mission and cannot observe it anymore. But for us to understand what is happening -- we need more data and we need your help!
We are using the Kickstarter platform to build community of people interested in working on this mystery with us. What are astronomers doing next? We need more data! Are you wanting to help? To learn? Join us!
This Kickstarter project will secure observing time on a global network of ground-based telescopes so we can catch the star when its brightness dips again. When will the dips occur? What will the dips look like? How long will they last? And last but not least, what is it passing in front of the star to make these dips?
Only with these new data, and the answers to these questions, will we be able to test theories out on what is happening around this star!
We have initiated observations on the Las Cumbres Observatory Global Telescope Network (LCOGT). LCOGT is a privately run global telescope network specifically designed for time domain astronomy, meaning that their network of telescopes is positioned strategically around the globe to ensure continuous monitoring of an object.
Our observation plan is as follows. From the 4 years of Kepler data, we know that the dips in the light curve are not periodic, so we need continuous monitoring throughout the year since we cannot predict when it will dip again. We also know that how much the brightness drops is also variable from dip-to-dip. The LCOGT data will not have the precision Kepler had, but will have plenty of sensitivity to detect the observed dips in this star.
What’s more, since we are observing this star from the ground we are also able to tailor our observation plan to reveal detailed information on whatever object(s) are passing in front of the star to make the dips! One way this will be done is by observing the star at different wavelengths, or colors, of light. These new observations will monitor the star’s brightness at an assortment of colors!
In addition to this, the data from the LCOGT are processed in real time, so when data are seen to pass below a brightness threshold, it will trigger more observations in the LCOGT network. Our science team will then alert for observations to be taken at larger facilities to get a better look.
The observatory has gifted this program 200 hours to begin the project on their new 0.4-meter telescope network, which will take us to the end of the summer.
With your support through this Kickstarter, we will be able to continue monitoring this star and it will give you the opportunity to be a part of it!
Our initial requested funds will cover all expenses for one year of monitoring the star. This will include a total of two hours per night dedicated to observing it. Observations will be dispersed for even temporal coverage throughout the night, and each pointing will cycle through a set of filters to give us the brightness at a range of colors.
Why do we need a Kickstarter?
Government-run professional facilities/observatories operate under a proposal processes, and have long lag times to award and schedule observations (~6 months). They are also oversubscribed, meaning that the observing time requested in all proposals exceeds the amount of time than they have in the schedule. Lastly, and critically important to this project, the government-run facilities do not have the capabilities for long-term, continuous, monitoring, which is what this project needs.
This leaves us with privately run observatories, where securing observing time is not free. The traditional approach to pay such expenses would be through a government grant (e.g. NASA, NSF). However, the success rates of these grant processes are below 15%, meaning that lots of great science gets turned down, and the sort of proposals that do get accepted are usually “safe” ones with certain and immediate returns. A project such as this one that needs lots of telescope time to observe something with an unknown chance of occurring is very unlikely to be funded by these traditional sources. That's why we're turning to crowdfunding.
Exploring the mysteries of space is exciting - and we invite you to to come along for the ride and experience it with us! Why not be a part of our team?!
Our connection with amateurs: One of the key elements of this project is that it has always been a community effort. First off, this object was discovered by Citizen Scientists, ordinary people who volunteer their own time to help dig through scientific data sets in order to advance science. And then again in late 2015 when the object’s weirdness went ‘public’, dozens of amateur astronomers responded to an alert from the AAVSO (American Association of Variable Star Observers; which is an international association, despite the name) to observe this star with their own telescopes!
This Kickstarter project continues on this theme, giving you the opportunity to contribute to the science you care about!
The new LCOGT data we will get from this Kickstarter campaign will continue in a collaborative fashion with the observations collected by amateur astronomer observers. These data obtained through the AAVSO in response to the first alert are valuable as they increase the time coverage and sampling. But they have a corresponding issue in that there is a lot of scatter in the data and each of the many many observers has systematic offsets in their measurements with respect to each other.
The cause of these observer-to-observer offsets can be due to many things, but most often it can be traced back to two things: how much experience an individual observer has had with obtaining and processing this very precise type of data, and what instructions were given about how to observe the star and process the data. (In the first alert from the AAVSO, instructions were not specific because so little was known about the star’s behavior.)
Just have a look at this graph here to get an idea of the AAVSO data set for this star:
This graph shows the data contributed by dozens of amateurs. But even excluding the obvious outliers, there is a scatter of at least 5% (or 0.05 magnitude) from the average brightness in either direction.
If just AAVSO data are used alone, the myriad of offsets and random sampling from many observers (even if greatly reduced by giving more specific instructions to the observers) may always obscure the fine details of the brightness behavior of our star. That is, with a patchwork of observers, dips ~5% or smaller may not be recognizable in near-real-time with AAVSO data (and the Kepler data show there are very few dips greater than this level).
Not all is lost however. The LCOGT data will have the dense sampling with a single consistent system, so dips below the 1% level can be spotted. This also means that we can use the LCOGT data as a very valuable training set to help amateur observers to improve their techniques. By educating amateur observers in this way, their data can be made more precise and can be corrected for systematic offsets. And by accomplishing this, we will greatly increase the number of observations to be used in our final analysis.
The LCOGT network of telescopes with identical setups around the world provides the security we need for continuous monitoring and the calibration of the contributions from the AAVSO observers: this is a value that cannot be understated.
This project requires a tremendous amount of work, but by working together we can optimize resources and extend the coverage of our monitoring. By helping us through this Kickstarter, you can be involved in making it happen!
- This project will take patience. The Kepler space telescope observed this star continuously for 4 years, and only for ~5% of this time was the star ‘dipping’. Plus, this star’s dips are not periodic, and so we cannot predict when another dip in flux will occur!
- Will this project give us an answer? This project promises new data with hopes to understand this system. This project will be highly rewarding if we catch the star when it dips. But the possibility remains that over the course of the observing campaign the star will do nothing exciting. So please keep in mind that “new data” does not necessarily mean “results”, whether in the immediate or distant future. But also keep in mind, if we don’t look, we will never know!
- This project is not designed to search for signs intelligent life around this star. Observations listening for signs of communication from the star are part of another, ongoing project using radio and optical observations. The data for this project will be used to explore ALL possible scenarios to explain the star’s dips in brightness. Since we are taking our observations in different colors, we will be able to determine something tangible about what is blocking the starlight. While it is possible that we will find that the dips are not consistent with any of the natural explanations offered so far (which would be the most exciting result!), such data by itself would not lead us to immediately conclude that the “alien megastructure” hypothesis is correct.Kickstarter上の説明責任について詳しく知る