21 New Tabby's Stars with Dr. Edward Schmidt

in 2015 the story of tabby star named after discoverer dr. Tabitha Pelagian captivated the science news cycle for months this was largely driven by the idea that the Stars unusual dipping could in a long shot have been due to the activities of an alien civilization building a Dyson Sphere this was never particularly likely but it was on the table because all of the natural explanations that were being advanced at the time were being shot down as implausible in the case of the stars the mystery continues to this day though it's almost certainly a phenomena involving dust in some odd juxtaposition around the star but one thing that stood out about this star was it's apparent uniqueness there wasn't anything else quite like it in the Kepler field of view where tabby star was discovered in the intervening time at least one star similar to tabby star was found but my guest today has found quite a few more looking through past sky surveys and what's more he seems to have found two completely different types of dipping star the mystery of the dipping stars grows deeper [Music] you have fallen into event horizon with John Michael Gautier [Music] [Music] in today's episode John is joined by dr. Edward Schmidt dr. Schmidt is a professor emeritus at the University of Nebraska Lincoln having taught physics and astronomy for over 40 years he has well over 50 peer-reviewed articles mostly focusing on variable stars in professional journals including the Astrophysical Journal the Monthly Notices of the Royal Astronomical Society and astronomy in astrophysics his most recent paper looked for analogs of tabi star using previously available survey data welcome everyone to event horizon with me John Michael Gautier if you enjoy what you hear fall into the event horizon hit the like button and become an active subscriber by ringing the bell dr. Edward Schmidt welcome to the program thank you now dr. you have a very long history and studying of variable stars and in the past this has been things like si Fiat variables which have been a very important science because obviously that's how it when Hubble discovered the expansion of the universe but we also seem to have a new type you know these these things like voyage ins star where you have very very irregularly dipping stars can you give us sort of an overview of what what do you your attention as a as a scientist that studies variable stars towards this particular one well of all the stars that we talk about these these are one that were you know a new new phenomena we didn't really understand and there's a lot of efforts to try to explain it but so far I just think we just don't really understand it and so I thought that'd just be an interesting area to work in and try to contribute a bit to it to hope in hope of maybe helping to fear what's going on with them I think there's a lot of interesting astrophysics there once we sort it out so it seems like an attractive area to work in this is not normal you know variable stars we have all kinds of variable stars cataclysmic variables and then you know very regular variables and all that but this is something completely different this is do you think this is intrinsic the star itself where in the case of watching star you know that's one of the ideas that's been floated around but I think the most likely explanation is that these dips are due to something or being a star that blots part of the light and but even that's truck problematic because of course they they come they go and there for long intervals between them and so it's but that seems like the most attractive direction to look right now in other words it sort of looked like some sort of dust something weird regarding dust but when they looked at voyage and star in particularly they didn't see any infrared emissions from this so is that really the disconnect there no infrared that's that's one of the troubling problems is that whatever energy they absorb ought to be readmitted in the infrared and we ought to be able to see it so it's that's one of the one of the mysteries we we're gonna have to figure out to this in regards to that dust could that be something that's in the interstellar medium well that's one suggestion is it's in the under stellar medium but the problem with that idea is that if the interstellar medium is introducing this kind of behavior in these stars you'd expect to see it got a lot of stars and we don't so let's put B we're looking through some particular place where something's really peculiar better I think that idea that the interstellar medium is doing it is probably not our top idea right now so whatever it is has to be at least in voyage in the case of Biogen star now these other examples that you found may be different but the in the case of voyage in star it must be cold dust right it must be orbiting fairly distant or elliptically from the star at least far enough out that it's not real warm yeah that's right now you have looked for more you've used past sky surveys and you've identified 21 stars that seem to also be doing this which is important you know because you want multiple examples of a phenomenon so you can study a sampling instead of just one so you have found more what Skyy serrated you use the Sky Survey I used to get started with was one called very northern NSPS or northern sky variability so today and this was done at Los Alamos the data is about 20 years old now so it was done about 20 years ago and it was a survey where they photographed the entire sky that was available each night twice usually so there there's a lot of data there to look at and to find these stars a very real kind of star it appears so there's a lot of stars there you can look at and a lot of data on each one so it was a good place to start rare but not unique in other words yes right it seems to me that kind of a star survey would have caught all kinds of variable stars right in addition yeah so so you would see you know if you're just a stellar physicist or something like that you're looking at it you know that would be it seem to me to be a very useful tool but why didn't anybody notice in this survey before this time that that there were sort of weird variables going on there well I think the answer is that it's a very they're very rare and you'd have to look at a lot of stars and nobody really expected stars to do with these do so once knowing what Boyajian started and I I could write a computer code that would weed out stars that might be like that and so my toad went through and looked for that kind of behavior and then it came up with a thousand or 1500 stars that were possibly and then of course I looked at him more carefully and we did it's out of the 25 21 now you seem to have isolated two different types of variable star of this nature can you go into that yeah and that was one thing that surprised me is the ones which have a lot of dips which I was one cycle rapid dippers we're completely unexpected we never seen anything like that I don't think really or at least not looked into it and then they're the ones which were more like Boyajian star where they dipped but not very often every year two or three or something so there are definitely two kinds and whether they're just two varieties of the same thing or more extreme cases or whether they're really something different than something we have to to work on I noticed in your paper that you saw basically two different classes of star that that we're dipping like this and maybe they're related maybe they're not so you have sort of the f5 type almost sun-like stars that Biogen is and then you also have red giants could you tell us about that yeah that was a surprise I wouldn't have expected to find two groups like that and both the groups are pretty tight so they look like real groups and statistically they're both significant so that's that's a surprise and that raises a question are they doing the same thing even though they're somewhat doing types of stars or are we seeing two different phenomena and that that's a question that again we have to get into and oh yeah at this point I I don't know which is more likely calling other scientists to dig in and try and figure this out now is does that does that hold I mean do the rapid dippers versus the slow dippers does that sort of break along class lines I mean is it is a stellar type is that affecting what these things do or is it just you seem to be seems to be huh it just seems ya know there's some some of the red giants or the rapid dippers and some of the main-sequence stars the rapid dippers and so it it doesn't seem to be related to that which suggests of course then that the mechanisms of the rapid ones and the others or is the same but that was also surprised when I noticed that they were mixed together that way could it be certain stellar types actually or if this is dust you know say very very tiny dust you know submicron dust that's you know cigarette smoke like could it be that certain stars are able to just blast it out of the system and other stars it's able to hang around somehow could that could that be responsible for different stars doings I suppose it could be something right there going on haven't heard anybody mentioned that particular idea but that certainly something that we ought to think about interesting again these the to get back to intrinsic variability in the start itself a red giant doesn't seem like it could do this on its own so it has to be some kind of dust almost rain well we're talking about the Dipper yes but red giants some red giants do very intrinsically but that's that's a different mechanism that we understand pretty well yeah that's an old I mean we've known about that for a long long time but now now if this is where they're dipping were you know almost done pretty well unpredictably I guess you never know one that could go into a cycle now gut-feeling as an astronomer where would you go first if you had to say well let's start looking where would you start would you start with like cometary material or something like that or disintegrating moons I think is one of the things that's been coming up well yeah and one of the things I noticed with the rapid dippers is that from year to year they they came a lot and there's one in particular which was dipping quite rapidly and by the fifth or sixth year of the data it had nearly stopped and that makes me think that maybe this was the result of some kind of a cataclysmic event and people suggested equation between asteroids or comets or something like that or even somebody suggested that you might get something funny going on if a planet is absorbed into the star which we think can happen and so one of the things I want to do is go back and try to look at some more old surveys to see what these stars were doing 30 40 50 years ago if we can find the data and see if if maybe this phenomena is something is triggered by a cataclysmic event and there's a lot of debris around and then it goes away and if it's blowing away on a time scale I can see in the graph the dippers that's going to suggest it doesn't last very long and that's right it's rare one thing I was speaking of past surveys infrared which was one of the big questions with Boyajian star is the lack of infrared now and these new candidates that you found can we go back and look at like the IRS data or something like that from years ago and see if see if there's a different profile and infrared for these things that if we see you know one has is emitting brightly in infrared we can say well this is some kind of disk you know this is something maybe not a protoplanetary disk but this is something you know debris around the start is it is that a possibility can we go back and look at past data like iris and see if we can characterize what what these new candidates are yeah that's that's something it should be done so it's on my list of things to do is to go back and try to find a whatever infrared available is available and and maybe that'll tell us something it may be like boy I turn star of course it may just be there's no rain for it there and then that doesn't help but that's when we go look at but could it be like with Boyajian star could that be a threshold thing that we just don't have the equipment to see the infrared if it's fairly weak yeah and I think that's probably a possibility I haven't gone through and done the calculation that's another thing I tend to think about a little more but yeah you're right that might be something to look at to now of course boy I didn't star had a sort of mistake my because it was an overplayed card but people talked about alien megastructures it is any of this in it of any validity or I mean is this a valid way to practice SETI by looking at these stars well and of course the SETI people did look at where I was in started to see if they could find any anything and of course they they didn't so from the SETI point of view I think that worth looking at and after I got the paper finished I actually sent it to some of the setting people and suggested they might never look at these stars so I think that's a worthwhile thing to do I think so you know just looking at it the whole picture I think that's probably down at the bottom a list of possibilities you know it's extraordinary claims that require extraordinary proof so always always look at the natural first because it's very likely very likely natural which my my my own gut feeling is that we're looking at some sort of dust and a weird juxtaposition around these stars but that in itself is interesting scientifically speaking because it's so rare you know right now what what you know the other weird thing about that is that I mean an f5 star like Boyajian star or a red giant doesn't really seem to be the ideal place for an alien civilization to go to go and set up shop and he views on that well I mean these stars aren't that different from the Sun so I really don't know where where you'd expect to find alien civilizations but these stars are close enough to the Sun in their properties that they their long ride announced that they could produce life and so on so I guess I really don't don't know how to answer that yeah that's it well no one does because we've never seen an example right until until someone sees an example which you know one wonders if it if we ever will yet you can't really say although I remember do you remember the French astronomer Luke Arnold I think in the 2000's thought about well what would louvers look like in a light curve or giant triangles or something like that that you know might be a very cheap form of announcing your presence to the galaxy just put a big mylar shapes or something like that now back to the variability these stars so that they don't look like they're intrinsic that don't look like they're that they're the interstellar medium do you think that there's do you get a sense from your study that there is a a single explanation for these or is it a case-by-case basis that all of these stars may all be doing different things do you think it's one explanation or do you think it's probably variations of a of an explanation I tend to think that probable they're they're fairly similar and what they're doing of course with any phenomena there's a range of parameters so different stars would do different things a bit but it strikes me that there's enough commonality monument that I would expect if there's probably a single mechanism behind it all now there was a recent law reason as in the last five or so years of another star system that turned out to be a really extensive ring system around a planet do you see Indian any indications in any of the data on these stars that that maybe this might be what's going on um I think it's a possibility and I don't see anything in the data to suggest it but people talked about it and tried to model it by having a ring systems that are transiting the planets so it's it's a another idea that's worth keeping in mind I think now but that again also would I assume I mean if you had a distant planet like Saturn is where you have a ring of ice I guess that wouldn't produce much infrared would it no probably not it's pretty cold and so that is that is one of the uncertainties of course if you're Indian bread is that things need to be warm enough to produce it and that's one way it can not be seen now what are the next steps so you're you're trying to get other researchers to go out and take a look right at these candidates and figure this out what are the next steps for for researchers now to go in and say well let's take a look at these what what has to be done next well there's several things the first one is to simply monitor them until they produce some dips again and which of course happens with the Aisin star they had to wait several years but then it did it again and that's how we found out that that it was probably dust because of the color change and so that's that's one thing to do and just to verify that there are more dips and to get better data on them it strikes me it's a really gonna be a hard nut to crack because with a lot of things if you want to study them you know study them and they do their thing but with this you you might have to weigh three or four years before one of them does something and so it it's gonna be difficult I think to looking at the stars carefully and with boys on star she did that they that spectrum a looked at perspective very critically and tried to see if there's anything in the spectra that gave him a clue and they looked at the infrared of course as we've mentioned and they did a lot of work trying to find anything else that might help and so I think the same things needed here is to look at these stars closely and look their Specter and nail down their temperatures better than what what I used those temperatures are not real acted so more active temperatures are help because I would show us if the region of the HR diagram is more tight than it looked at my diagram and then the other thing I want to do is go back to a lot of the surveys and look for more information on the stars I have now to see what they were doing in various try them to the power of a double question on that now you we have a we have in some interesting equipment coming online we have obviously tests which looks at closer stars but would test be able to see these these candidates and study them on on any type of cycle I think they're a bit faint for test these things tend to be around 9th and 10th magnitude their lungs magnitude some of them and I think that's probably isn't getting anything on them so we don't really have a closed example of this right yeah and another instrument telescopes coming online of course in the next year's is the large synoptic survey telescope and people mentioned that that maybe we can find more of these stars with it because of course it'll be surveying the sky for a long time but the problem of that is that it's gonna be looking at really faint stars so then if we find them we won't be able to do a lot of the detail work we probably need to do so if it's hard to know exactly what's gonna work out it captures or it will capture all sky surveys like every day and a half right so that's not really as useful as something like Kepler which captured you know what every 30 40 minutes something like that correct right but of course Kepler was was uniquely capable for that kind of thing and Betty we don't have it account or still we should be manufacturing kepler satellites and putting as many of them as we can we possibly can in space to look at all possible patches this guy that we can I was just it was an amazing amazing spacecraft that allowed for citizen scientists and scientists come together and find some really strange stuff like Boyajian start and I I wish the philosophy that was that was applied you know for Kepler would be applied to more spacecraft you know so how close are these to Boyajian start and behavior and now I know that you sort of had a less capable system going than than what Kepler could do but how many of them look a lot like it I mean almost exactly like it they are is it a good fit or is it just that you know these stars have some variability and just how they act as far as dipping goes yeah they it's hard to know how much they're like my odds and star I looked at another skies where they just to keep what they were doing more recent times and some of them were a few that we didn't see any dips with all living right under rule but given are we infrequent they are in Boyajian star it wasn't surprising that we just didn't get some and some of them so but you know kind of going through it specifically looking at all of the slow dippers together it appears that there are producing dips at about the right rate to be similar to my eyes and star so that's another reason to look at more surveys and try to to make out a lot more or definite now the one thing also that I have to ask about what regarding pyogenes stars there also seems to have a long-term dimming trend over since 1890 was whatever survey they they were looking at it seems to be but do you see any indication of long-term dimming true and these other stars I haven't looked at that carefully it's it's difficult to do because of course you've got to worry about all kinds of systemic effects and even that our long-term dipping from that began like you said in there into the 19th century was questioned by people from of the time because of the fact that there could be systematic trends and so it's a very difficult thing to do I think with play a gene starts will establish now because it's been found in a number of data sets and it seems to be there all the time when when you can look at it so it's a difficult thing to do and so I haven't dug into that very much I tried it a bit and I did see some of those kinds of trends but I need to to really work it out a bit more before I can really be convinced that it's doing that same thing that's interesting because that would sort of maybe bolster the argument that it's you know cold comets crashing into each other and producing an increasing amount of material or you know evaporating body of some sort throwing out material then you get into questions of like well how fast can these stars you know eliminate that material from the system it seems to me that this is complex but when you look at the universe in real time as we can sort of do you're gonna see strange things of completely different than the stuff that you used to see you know you know where you would see things change over geologic time periods here you see them change over very rapid periods you know human life timescales is this an indicator that we are really gonna find some an increasing amount of strange stuff in the universe or at least this galaxies over as we build the instrumentation in the direction that we're doing so I think so because if you look back at the history of science every time you look at a new part of parameter space so you look at use a new instrument that can make measurements that you couldn't make before you always find things you didn't anticipate so I think I think there's gonna be a lot of new and interesting things come out of out of this time domain astronomy picking up speed well isn't it speaking of like the LSST I mean once that comes online interstellar objects you know the one of the big stories right now is is this interstellar comet comet Borissov or for that matter of moon we're seeing things you know that probably had to exist I'm sure many people predicted that you know interstellar flotsam would be flying through the solar system at any given time but now we're seeing it and it's like having samples of the galaxies coming at you so that you can study and ask you know what's different you know what what wherever this thing is from what's different about it and it I think with comet force of the early indicators said it's not different at all it looks like a comet yeah which has implications because I mean you know if you if you're if you're interested to study then that might imply that the materials are the same all the way across the galaxy and why wouldn't that hold true for everything you know including carbon compounds and we see them everywhere now with these dipping stars other people have brought out okay well what about and there's another example of this this that very very I don't remember the name of it but the very very strange star that recently came out in a paper where it looked like it had multiple planets transiting did you did you read that paper and does that strike you as being related to this or is that something else completely new yeah I think there's something else because clearly what we're looking at with these dippers is dark planets it's got to be clouds of dust probably and so I think I think that's a different a different sort of thing now I haven't seen that paper I saw these summary of it but I think it's something different now stars can produce things like carbon they can sort of belch it out there and could that be responsible for this is the star producing this dust yeah we do know that some stars do produce dust with the red giants that are variable our response was quite clear the dust that's in the interstellar medium but the trouble of these stars is they don't generally seem to be the kind of stars that have enough mass law to be putting much out there and so I haven't really thought that the star actually producing with dust is a very likely scenario I'm more of the opinion that this dust may have been produced by collisions in the asteroid belt or something like that where there was pilot material that gets broken up let me ask you this in the in the candidates that you found well I just started dipped a lot I believe 22% was the biggest yeah the deepest one are these things on level with that or do they accede to that some of them exceeded and then some of them are less one of the problems is of course I can't detect small dips like she could with the Kepler data and so we're only looking at dips that are at least a few percent and so we don't know anything about what the small dips are like if they exist but some of them have dips that go up to 40 percent or something like 40 percent now that's big it's a lot more than that yeah now a 40 percent dip that's just enormous in comparison to something like if you were looking at our star system from afar and you saw Jupiter transiting it might be like 1% whereas this is 40 percent so this is a huge structure that's passing by which would I would think really imply dust because dust can you know make big clouds here very few other things can so how do we tell now I know that with Boyajian started you can you can look at it and you can see differences and absorption between red and blue light so and you can say well that's very tiny dust that's absorbing that wavelength I this is going to apply to these new candidates right so that's one of the first things you should look for is is that sort of change right yeah and one of the problems of using all these surveys of course is most of them don't have any color information and so we can't get that information that's a good reason to keep observing them and and wait for another dip so it's gonna be a tough one you have to catch the dip and you have to catch it with the right equipment exactly so do you intend to you know I mean will the astronomers use a service like the astronomers telegram or whatever to try to coordinate and I mean is anyone in contact with you to try and really study this stuff yet I've gotten some people have written me emails suggesting various approaches we haven't really worked anything out but I think what I'd like to do is go through the American Association variable star observers because they they have members who have equipment that could you do this and they are able to keep in touch with them if anything comes up to needs observing so yeah so we're gonna we're gonna have to think about how to do that but it's still a little early in the game to work speaking of a so one of the coolest things is that there has always been this sort of cooperation between amateur astronomers and professional astronomers on observing stuff like this and that's how boy watching star was discovered - planet hunters and now AB so with all these guys with looking at variable stars with their telescopes and making you know good observations in their backyard and it's still going on the great cooperation between the amateur and the professional continues oh yeah and it's yes you know it's going on for a long time but it's a very important benefit to the astronomers to have the amateurs doing this kind of thing so so yeah you're right it's gonna continue and this is one place where I hope to provide some more information for us definitely well doctor I will what be watching carefully I hope that you're able to get some more insight on these new candidates and we can identify whatever weird Astrophysical phenomena is going on here thank you the saga of the dippin stars will continue as scientists work to unravel what's really going on with them but they illustrate something broader as new advanced instrumentation comes online in the coming years they will act as mystery generators as we gain unprecedented views of space and what must be the sheer plethora of strange unknown natural and even unnatural phenomena that may await us in Milky Way John the cars moving on its own it's just autonomously picking me up for the cheese club meeting you didn't get the handbrake looked at did you don't worry it'll stop its high-technology John it's no stooping pickle sticks on that note after the house repair join us next week for another episode of event horizon where I'll be interviewing a surprise guest plus a bonus clip see you then you

Channel: Event Horizon

Views: 56,165

Rating: 4.8845458 out of 5

Keywords: Tabby's Star, New Tabby's Stars, kic 8462852, alien megastructure, alien megastructure star, dyson swarm, dyson sphere, dimming stars, dipping stars, kepler space telescope, Alien civilization, boyajians star, tabetha boyajian, tabbys star, comets, melting moon, edward schmidt, Analogs of KIC 8462852, event horizon, event horizon john michael godier, john michael godier, godier

Id: ACKOD5mmH-0

Length: 33min 53sec (2033 seconds)

Published: Thu Oct 03 2019

Reddit Comments

[u/Taste_the__Rainbow]

21 is too many for that “disintegrating planet” explanation, right? Seems like too many.

[u/JamesSway]

Well, this just got really interesting 🔭

[u/EricSECT]

The deeper we look the more we find.... I lean towards some type of unknown astrophysical cause of dimming, for these particular stars, Tabby's Star and the approx 100 vanishing stars of Dr. Villarroel:

https://www.astrobio.net/also-in-news/short-lived-light-sources-discovered-in-the-sky/