We are astronomers Dr. Tabetha Boyajian and Professor Jason Wright. What is so mysterious about the "most mysterious star in our Galaxy"? Could it be a massive swarm of comets, an "alien megastructure", or something completely new? Ask us anything

Thanks for taking our questions, Tabby :)

This may sound crazy, but I was wondering how you would react if it was discovered that the dimming starlight was actually an alien signal, intentionally aimed in our direction?

After all, an advanced species wanting to make contact with more primitive life would be well served to transmit by starlight: something even our ancestors studied and tracked.

Somewhere in the muddle of data, could there be an alien message, waiting to be decoded?

Is it a reach? You bet! But isn't this what makes this so fun?

ps. Stuff that is fun is good for raising money :)

that is an interesting idea! If there was a message, it shouldnt take much to decode it (if they were smart!). We shoud search for evidence of prime numbers :)

Have either of you seen this transit model that sort of fits the lightcurve?

http://i.imgur.com/t8chJjj.gif

The assumption is that we are seeing a second close-in dim star and its host of planets all transit the primary star.

It is fleshed out here: http://imgur.com/gallery/6335i Some thought has been put into this but I cannot judge its accuracy. Is it totally crazy?

Very cool animation! not totally crazy! such a complex system would show evidence of any putative stellar mass companions in the ground based spectrum and spectral energy distribution. All we see is the presence of one star.

Perhaps the hypothetical system is composed of planets orbiting a neutron star and this system is in the line of sight but far enough away to not exhibit gravitation effects on KIC 8462.

Presumably the occulting planets wouldn't significantly show up in the stellar spectrum

neutron stars are very massive, but small in size. Planets arent large enough to block enough light.

http://i.imgur.com/t8chJjj.gif

I agree with Tabby. That's very clever and not crazy at all, but we can rule out an additional star in the system because KIC 8462 does not show any signs or being in orbit around anything. Also, this model only explains the deepest features, which in the light curve seem to be accompanied by lots of lower-level events that can't be explained by planets.

and... how does this model explain the d800 dip?

You guys are doing amazing work! I've read Tabby's paper and the G-hat series. No background in astronomy/astrophysics but this is amazing stuff!!

I have 2 questions atm:

(1) If Brad Schaefer's analysis is correct the star has been dimming for at least a century. It seemed to me a logical explanation for this could be that the star is actually losing mass. I did a back of the envelope calculation for how much mass that might be, tl;dr 1/20th of a solar mass. Could this be a plausible explanation for the possible long term dimming?

(2) Roger Pickard of the BAA VSS reported some interesting observations to the AAVSO. One set back in November and another more recently on May 4th. Have either of these been confirmed by anyone else to your knowledge?

can you give a little more info on this?

Sure, I assume you're referring to (2):

• November observations
• May observations

I reached out to Roger and he had this to say:

Interesting that you should pick up on that as the AAVSO queried both sets of observations with me as well (on behalf of the PI).

No, neither have been confirmed by a third party to my knowledge and I’ve been through both sets of observations myself several times but could find nothing wrong. I’ve never recorded anything quite like that before and I like to consider myself an experienced CCD observer.

OK, I see now. We had the aavso contact the observer and they couldnt verify the data - even though the user is very experienced. variability for this star on such short timescales has never been observed, and also not consistent with other data during these times. So to answer your question, it has not been confirmed.

If, after a long while, there is still no feasible explanation to explain the weird dimming of the star, how do you think the ET hypothesis could be tested?.

Unless we observe signs of obvious alien intelligence, like narrowband radio emission, SETI for this star will be a process of exclusion. That said, if we find that the eclipses are achromatic (the same at all wavelengths), that would be very strange and hard to explain.

if we find that the eclipses are achromatic (the same at all wavelengths), that would be very strange and hard to explain.

What natural explanation could you think of if this occurs?

nothing immediately comes to mind...

radio SETI observations to detect such signals

Hey guys!

So if not for PlanetHunters, we may have never found Tabby's Star.

Is there any chance there are other such stars in the Kepler Data and we just haven't chanced upon them yet?

Thats right - PH found the star!
once we knew about this star, we were able to go back and search for other stars similar to this - anything with similar varibility below the 5% level is tricky to identify this way without the help of human eyes.

Why have swarms of comets been the default lone explanation over planetary ring systems?

Boyajian et al. makes mention of the enormous rings found around J1407, but dismisses planetary rings as a probable cause due to the lack of symmetry in the dimming events. But would the curves not be highly dependent on the angle/orientation of the ring plane during transit? Additionally, the banding seen in J1407 (or Saturn for that matter) may be characteristic of a "mature" ring system, while younger ring systems may not be as organized.

Could the data potentially be explained by two separate planets with rings formed from moons whose orbits decayed past their Roche limit, accounting for the difference between D800 and D1580?

In my view, this could explain the magnitude of dimming, lark of IR excess during non-transit events, and fits with the age of the system. I'm sure I've missed some analysis that rules this out so thanks in advance for any insight you can provide.

J1407 is known to be a young star by multiple indicators, and so could be expected to have a debris disk and planets forming around it.

KIC 8462852 shows no signs of youth at all, and would not be expected to host a dynamically young system like that. Indeed, it is KIC 8462852's apparent maturity that rules out most explanations that involve dust, disks, protoplanets, etc.

Thanks for your reply!

I think I was using the term planetary ring incorrectly. I meant to refer to something like Saturn, rather than imply KIC 8462852 has a planetary nebula.

Are planets with large ring structures ruled out by a mature star?

not necessarily (just think of Saturn). All scenarios have to fit under the scenario-independent constraints listed in the Boyajian paper though, which makes satisfying the dynamics quite tricky, if not impossible for such a ringed system.

Q1: How many dips have been observed to date? Is there any data in addition to the dip around day 800 and the cluster of dips between days 1500-1600? If not, is there any reason to believe we want to look every ~800 days or so?
Q2: The comet theory sounds very unreasonable. What is the second most accepted possible natural cause? Q3: The lack of a heat signature shouldn't mean it isn't artificial, right? If a civilization can build such a structure, wouldn't it be reasonable to think they have a better understanding of thermodynamics than we do?

I LOVE this story. Thanks for the hard work!

Q1: In the Kepler data there are a round a dozen dips- most are very small then there are the ones at d800 and d1500. While no periodicity can be found, a priority will be to observe the star at ~800d increments - the next to occur in may of 2017! [wishing the Kickstarter is successful for this!]

Q2: comet is currently the most sensible scenario, despite its issues. There is ongoing monitoring in the infrared to test whether a catastrophic collision could be the solution (this would have to mean the detection of an infrared excess is delayed for some reason).

Q3. leaves a lot to our imagination. we have a lot to learn about it!

Thanks for your interest - hope you stay involved thru the kickstarter!

One more question:

Let's say the occulting material is achromatic. Where do we go from there?

no need to limit Qs - hats why we are here!

A detection of an achromatic signal for this star would have to hold up to rigorous verification! We need more data!

Regarding the controversy over the potential century long dimming, which side of the debate are you leaning toward at the moment?

This is a subject that we are not involved with. But we eagerly await a confirmation! Stay tuned!

If you are unsuccessful with your Kickstarter, do you have a plan B to get funding? Great work, by the way and good luck with the project!

We will be successful! Help spread the word!!!

Hi! Thanks so much for doing this.

I assume you guys run programs that try to fit shapes to the transit lightcurves by tweaking properties of the shapes until the dip matches, is there a particular shape that's your best or favorite match? Or is my assumption bogus?

Bonus: I read the April 2016 report about the likelihood of technological civilizations having appeared before us being fairly large given some assumptions; if you were forced to defend the alien megastructure hypothesis, would you think it is already long abandoned? Sorry if my SETI question makes you cringe!

Hi! Thanks so much for doing this. I assume you guys run programs that try to fit shapes to the transit lightcurves by tweaking properties of the shapes until the dip matches, is there a particular shape that's your best or favorite match? Or is my assumption bogus?

the more variables you introduce, the easier it is to match a model to observations. New data coming in will have color information, which can be used as a prior to any model of the dips

as for the bonus: only time will tell!

Are there any chances that the star has giant number of sunspots, may the star has vast magnetic fields. As sunspots keep changing their positions results in a unpredictable light patterns?

Good question!
Stars of this type (temperature and evolutionary state) dont have the right kind of atmosphere to have star spots like our Sun. Also, the rotation period of this star is less than one day, and from what we know of Star spots, they last for much longer than this. We may also ask the question, if such a phenomena were taking place on this star, why dont we see it in other stars?

OK, You've made love to my scientific mind with this answer.

Thanks for your interest!

Do you get frustrated by the media coverage?

bad media coverage - yes.

My day job is working for many politicians (and companies) doing their marketing campaign. My observation is that we don't have a science problem, we have a PR problem in many regards.

In this case, its the sensationalism that is frustrating. While I understand that all stories need a 'hook' (and aliens are a good hook), some have gone over the top. :)

When will you be observing the star with the greenbank telescope?

our observations will be scheduled this semester - exact time TBD. Will be sure to post updates on it!

If your Kickstarter is funded and as successful as possible, what would be the best outcome of your experiments?

an answer!

First of all, thank you for your work. I'm a big fan and I hope I could do more to help and be more implicated. My question is: As far as you know, are there any new interesting projects/technologies/telescopes planned to help further our research into KIC 8462852 and/or other potential interesting systems/stars/planets?

The only way we can figure out what is happening is to get more data! we have launched a kickstarter to make sure the star is monitored - this is critical to testing any theory to what is happening to the star.

If someone purchased the rights to this star would any accompanying alien mega-structure be included?

why not?

Last question: Have either of you gotten approval for radio telescope time to observe the star in the future? I heard SETI already did a very brief observation but it seemed far too short to rule anything out.

we love your questions! Actually, we just got news that our radio SETI proposal to observe this star with the greenbank telescope was awarded 25 hours of time!

Kepler is now pointed at a different region of space. Is it still capable of detecting similar events around other stars or has it's mission changed since the failure of the gyroscope?

the new Kepler mission (K2) only observes each field for ~80 days. This makes it kinda tricky to detect really similar events, since our star is 'active' very infrequently.

We ourselves are trying to observe the star with a Kickstarter to buy time on a world-wide network of telescopes to keep the star under constant surveillance.

What type of data from new telescopes will help demystify what's causing the dimming? Is there a telescope that would tell us "Yup it's comets" or "Wow, it appears to be an artificially constructed structure", or is thing going to be a mystery spanning multiple decades simply because we don't have enough resolution to tell what's going on?

we are taking data in several different 'colors' of light. When we catch it ipping again, the shapes and dip depths will be able to tell us what the orbiting material is made out of.

Assuming the long term diming is real. How would that combine with the faster irregular diming to form a bigger picture? How would it affect the likelihood of the various proposed theories?

century long dimming would certainly be an additional piece of evidence that the star is abnormal. Therefore any proposed theory to explain the observations should be able to explain both (vie Occham's razor). This could help or hurt any theory proposed to explain the Kepler dips.

Is there any kind of observation or analysis that could be made with current technology that would confirm an alien mega-structure hypothesis?

smoking gun would be a signal from such a system directed to us.

What allows Alien Megastructure to be a possible valid solution? Like what does it look like in terms of shapes, sizes, of the objects required to block the light. Are they rectangles or something like that? Mirrors?

when invoking aliens to explain things, you have a large number of unconstrained variables in your model. could be anything!

First, thanks for hosting this AMA. Big fan of science education and the value it brings to society.

What do you think is the best explanation for dark matter and energy and, do you think that could be contributing in any way to the observations?

we know little of dark matter/energy. Observationally all evidence of it is indirect. To this end, it is hard, if not impossible to invokw such a theory to explain our star.

Are there any possibilities that the star is surrounded by binary or ternary star systems that are resulting in a non-uniform rotation of giant planets around the Tabby's star which are causing weird light dimmings?

we find no evidence of close-in, massive companions to the star. Lack of periodicity is also an issue in invoking such an explanation

Is it possible the object or objects blocking the light are not orbiting KIC_846258 but are actually smaller objects nearer to the earth end of the line between the star and us? Perhaps objects nearly on a trajectory from the star toward us or away from us toward the star?

a couple things. any objects close to us do move in our line of sight - but these events happen on very short timescales (seconds to minutes) and the dips we see for our star last days. Also, a nearby occulter would pass in front of many Kepler stars as it travels, and we only see the signal in this star.

I sent a PM to Dr. Boyajian on this...

...but have you considered using any of the Open Use time at the various observatories in Hawaii? (eg., Subaru, Keck, Gemini, etc). I know that Subaru, at the very least, has open-use slots and any astronomer is allowed to submit a viewing proposal.

This is a good way to get targeted observations if an unplanned event occurs. Monitoring the star take a huge amount of time, and we can use a small network of telescopes for this (see out kickstarter!). Once a dip is seen, then we can put in a request to the larger observatories to study the star.

Will the James Webb Space Telescope be able to provide any follow-up observations on KIC 8462852?

JWST will be equipped with some super sensitive infrared instruments. There is a chance that observing it could reveal something new about it. but as Jason pointed out, logistics might be a bit tricky...

Do you believe that Elon Musk's goal of sending humans to Mars by the year 2025 is realistic? Why or why not?

I think it was realistic 10 years ago. I think it's a good goal for today, but probably too optimistic.

yeah, humans have not been to the moon in my lifetime. Its time.

Have you been able to rule out an unseen exotic companion such as a preon star or a primordial black hole? I know that such objects are as-yet undiscovered and purely theoretical, however maybe they're exceptionally rare or only observable under unusual circumstances?

black holes are massive, and we are able to rule out any massive close in companion. The presence of a black hole also produced gravitational lensing, which makes things brighter, not dimmer, so its kinda hard to make that work

question 1: If the dimming would be to natural objects orbiting the star, i guess the mass must be so huge that the sun would emit a doppler frequency - so no natural objects that massive in orbit ?

which leaves 3 options: 1. Something massive fell into the star -> question 2: what would happen if Jupiter fell into our sun ? 2. Some object within the thousands of lightyears blocked the sun -> question 3: have you calculated some statistics on how probable this would be with all the stars Kepler had a look at ? 3. something non-natural is orbiting the star :-)

1. correct. we are able to rule out any massive close-in objects in orbit.
2. good question - depends on how it fell into the Sun! (its actually kind of hard to do)
3. the probability is difficult to estimate, especially with a statistic of 1.

As a complete layman, it was interesting to hear about such a strange object and also about PlanetHunters. That service helped me understand what light curves were about, and in a fun way. And even more interestingly, in a useful way.

The question: How can we help again? There is the Kickstarter, and maybe more services might prove useful. For example, open source code/tools, artistic content, communication, etc... I don't expect a large spectrum of choices obviously, but I am curious about your input on that.

Im glad that you have has fun with Planet Hunters - Its quite addictive and fascinating to see how stars behave.

If you are interested in contributing (not thru the KS) and have a special skill to offer, feel free to contact us with ideas you may have (we get a lot of email about this, so excuse the slow response time!). Again, thanks for your interest!

Are there any similarities between Tabby's Star and KIC 12557548 ?

KIC 1255 was discovered by Rappaport - a main contributor to our discovery paper. KIC 1255's light curve is unusual (and made it in Jason Wright's G-hat paper on SETI) but no similarities to our star.

Can you explain in simple terms the controversy over the recent papers claiming the long-term dimming trend of KIC 8462852? The paper I read in the most detail checked the star against reference stars nearby to establish a normalized brightness for comparison, which seemed reasonable. And the later rebuttal was apparently based on using check-stars that were too close to crowding stars, fouling the data? Do you have any thoughts on an explanation for this dimming trend if true?

Its a very interesting issue! We await further confirmation on whether such a dimming is seen - this type of behavior for a star is unprecedented from what we know today.

Hi Tabetha,

If it turns out not to be aliens, can I get you back to doing interferometry? I need to know the temperature of my M dwarfs.

-Not Andrew

I am NOT done observing those little buggers. Slightly related, you think GJ 725B has a Dyson sphere?

If it is aliens(I'm hoping it is) what would happen?

very good question. I dont know! Its reassuring that the system is ~1500 light years away.

I read most of the comments here, and you rulled out most of the proposed hypotheses... so my question is, what do you think? What is your best explanation?

short answer - we need more data to say anything certain. One thing for sure is that nature has a much better imagination than we do, and from what we have already, this is going to be a tough nut to crack!

What do you think was before the Big Bang? Every time I think about it it freaks me out.

You are not alone - I bet its pretty freaky too.

What is your opinion on the reproductive instincts of the common goldfish?

Astrobiology is not my digs. Sorry!

If we believe that (a) there is something blocking starlight; (b) all things emit IR, and (c) whatever this thing is doesn't emit IR, why are we so afraid to put any stock in it being unnatural (something built)? Given the lack of IR ( and isotropic nature of natural objects) + Drake Equation, wouldn't we want to make a more clear case for ET? Such a thing would surely get you your Kickstarter goal and potentially garner scientific support. Of course I understand the personal brand risk. It just seems like people are far to easy to dismiss what might be a very real possibility.

We havent dismissed it if we are talking about it... We just need more data to say anything for sure - esp wrt such a potentially groundbreaking discovery

As a complete layman in all space subjects and probably even most subjects to ever exist, I keep asking myself some very naive questions.

For example, from some rather weird hypotheses:

• The space industry is opening new paths to access space with low cost solutions such as nanosats (CubeSat, 1-10kg), or picosats (0.1-1kg).
• We are now interested in one particular star. Sure it's new and we might find some answers soon about whether it keeps being interesting or not, but what if we don't in 5-10 years.
• I believe sometimes some folks build giant telescopes, and sometimes array of telescopes.

And with those hypotheses, I came up with:

Would it be possible to deploy a rather spatially-large array of micro telescopes to provide more specific info about one star at a time? Sure it might cost R&D and much more, but is it theoretically possible? What kind of dedicated tool can be of use with that particular star? (In my even more naive dreams, I was thinking about super super super large arrays to be able to get some kind of minimalistic image of the star itself, like some 32x32 pixels image, instead of just tracking an almost-infinitely small bright point. But because of shame, I would never ask that kind of question here).

I like your thinking! A mission specific satellite to study this star would be a dream.. But this is way out of the scope of what we can do (practically speaking, it takes a lot of $$ compared to ground based observations.)

a bit off topic.. still working on "the telescope above the clouds"-idea http://www.robosoft.de/kickmiss/skyscope2.png ... would it be any good to have telescope at 20km but in bright sunlight ? The 5% atmosphere might still be worse than 100% and clouds but no scattering of sunlight ?

what would you be observing? and with what kind of detector?

hey this is Robo Durden from the Kickstarter comment section ! watching Tabby's star with a 0.4m http://www.meade.com/lightbridge-16-f-4-5-truss-tube-dobsonian.html of course. So what about no clouds, only 5% atmosphere but bright sun ?

ahh, I recognized your name!
Honestly Im not sure the answer to your question as in what it would take. but as Jason mentioned observing at night is the way to go. during the day the background will kill any obs.

I have a question.

1. Are you currently working and coloborate only with people within the USA or other countries too?
2. Is there any other groups outside of the USA which is interested in this project?

Thanks, that's great wat you doing. :)

1. Yes, we are an international collaboration - just check out the affiliations in my paper (http://arxiv.org/pdf/1509.03622.pdf)
   
2. This has captured the interest of many people worldwide!

What do you think about the movie Predator?

is this Q meant for this AMA?

Yes.

went way over my head - at least Jason is up on pop culture :)