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This is an old revision of this page, as edited by Synchronist (talk | contribs) at 08:43, 10 September 2019. The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

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The brown dwarf with rings hypothesis

The hypothesis that KIC 8462852's dimming is caused by an orbiting brown dwarf with its own system of rings seems promising in terms of explaining both the long term and short term pattern of those dimmings; but once again, wouldn't this also cause a massive change in the overall spectral signature? I.e., when are we going to come to terms with the Liverpool data, which shows basically no change in spectral signature during the dimmings? (And am I correct in thinking that the brown dwarf paper never once uses the term "spectrum"?) Synchronist (talk) 07:27, 22 December 2017 (UTC)[reply]

The smoking gun: Researchers found less dimming in the infrared light from the star than in its ultraviolet light. Any object larger than dust particles would dim all wavelengths of light equally when passing in front of Tabby's Star.[1]

References

  1. ^ Landau, Elizabeth (4 October 2017). "Mysterious Dimming of Tabby's Star May Be Caused by Dust". NASA. Retrieved 4 October 2017.
The article does mention the negative Liverpool spectral results, and I expect that text will eventually be revised or dropped from the article once scientists have more time to reconcile the multiple spectral observations. The ringed-dwarf model appears to explain the data extremely well. However we may have to wait for the 1600-day cycle to repeat before we really get to overhaul this article as 'case closed'. Alsee (talk) 20:29, 27 December 2017 (UTC)[reply]
Alsee, could you point me at the mention of negative spectral results in the Landau article?Synchronist (talk) 05:56, 28 December 2017 (UTC)[reply]
Synchronist, your post confused me for a few minutes. Then I realized it was because an ambiguity in my post had confused you. The Landau article only mentions a positive difference in spectra. When I said "The article does mention the negative Liverpool spectral results", I was referring to the Wikipedia article mentioning Liverpool. Our article says "Initial spectra with FRODOSpec at the two-meter Liverpool Telescope showed no changes visible between a reference spectrum and this dip. Several observatories, however, including the twin Keck telescopes (HIRES) and numerous citizen science observatories, acquired spectra of the star, showing a dimming dip that had a complex shape". It seems likely that the initial Liverpool results were either wrong or inadequate for detecting the spectral signature, but when we have conflicting sources we report both unless&until reliable sources come to sufficient agreement on the issue. Alsee (talk) 07:47, 31 December 2017 (UTC)[reply]

January 3 paper in AJ Letters

I have added the paper itself as an external link because I did not use it as a source directly. For that, I have the plain-English National Geographic writeup, which also supplied the SETI director quote. @Robertinventor: told me that the new study also disproves some of the other hypotheses (in addition to alien megastructures), so the rest of the article may be in need of an update. Darkfrog24 (talk) 02:10, 5 January 2018 (UTC)[reply]

@Darkfrog24: Yes the latest research disproves many of the hypotheses. They strongly favour circumstellar dust as the top hypothesis, though there are still other hypotheses that are viable involving intrinsic variability of the star and some other ideas including a huge interstellar black hole debris disk in between us and the star (see [1]) which Jason Wright still thinks is a viable though less likely hypothesis.
In particular, there was no neutral sodium and no ionized calcium which rules out most hypothesees involving neutral or ionized gas according to Jason Wright - at least down to the signal to noise ratio of the observations. If there is any gas then there isn't much of it present.
For details of what they have found explained in a less technical way than the paper, see the second part of his post about the findings in the article he co-authored here: [2]. The observations strongly favour very fine dust, less than one micron in diameter- but rather a narrow range of dust grain sizes and larger than is typical of interstellar dust (see end of section 3.1 of the paper [3] which cites earlier work in 2016 on the dust size). So - the preferred hypothesis is very fine dust, cirumstellar and not associated with either ionized or neutral gas. Altnernatively it may be due to intrinsic variability of the star but some of the hypotheses of that type are ruled out. The Jason Wright post goes into this in detail in part 2.
I agree the article needs to be worked on to make this clear - we need to retain the disproved hypotheses since readers will want to know the status of them but make clear which are the most strongly favoured contenders as a result of this latest publication. Robert Walker (talk) 17:27, 5 January 2018 (UTC)[reply]
The circumstellar dust hypothesis, though it fits the data so well - is not without problems - they need to explain how such fine dust - and also optically thin (not so clumped as to be opaque) can survive without being blown away from the star. As Jason Wright says in his blog post the remaining hypotheses still all have problems but other hypotheses have been ruled out pretty much completely. Robert Walker (talk) 17:29, 5 January 2018 (UTC)[reply]
With the salient point of this discussion being the number of "loose ends" connected with the January 2018 "mega-paper" and the now-dominant dust cloud hypothesis, please allow me to first establish a clarification, and then throw yet another "monkey wrench" into the works: the 2018 mega-paper is to be congratulated for having a quite nice "summary of findings", and one of which -- as per the drum which I have been beating for several months -- is that there is in fact no change in spectral signature during the dimming events! With the understanding that this does not rule out from a physics standpoint the dust hypothesis -- a spectral signature being of course a function of gaseous atom electrons jumping from one orbital to another, whereas differential color absorption is a function, in part, of intervening particle size -- do we not always use "dust" and "gas" together in speaking of astronomical phenomenon; i.e., are there examples of known dust-based structures -- i.e., the rings of Saturn -- which do not have an associated spectral signature? And I ask this question in all honesty. Synchronist (talk) 05:01, 11 January 2018 (UTC)[reply]
@Synchronist: First sorry for the delay in this reply. Yes that's an interesting question. There was no sign of any spectral extinction or emission lines. Yet there was plenty of reddening suggesting selective absorption of the shorter wavelenths and so probably dust. So that suggests a lot of dust and not much gas. Usually there is either only gas, or gas mixed in with dust.
Anyway I've tried to find out more. And yes seems, this is something of a puzzle, for instance comets would normally have gas mixed in with the dust. That was an argument against the comet hypothesis until someone came up with a model where the comets are in a very elliptical orbit and then the comets outgas when close to the star - and what we see is the dusty coma from the rest of their orbit. Another difficulty is the lack of an infrared excess - what happens to the absorbed light if it doesn't turn into heat? And the dust is so fine - the finer dust - that it must be constantly replenished - so how does that work? Anyway the comet idea with the very elliptical orbits (not surprising for comets) is here: [4]
As I don't know the answer, I thought I'd post it as a question to the Tabby's star reddit here: [5]. Do join in and comment on the discussion there if you wish to. Hopefully get some replies as the reddit is quite active. Robert Walker (talk) 13:43, 19 January 2018 (UTC)[reply]

@Darkfrog24: @Synchronist: You may be interested, new paper by Jason Wright [1]. It could be useful for a rewrite of this article - it lists the main remaining contenders now that it is close to certain that what we are seeing there is dust with no or hardly any gas. The main ones are

  • Not instrumental effects - completely ruled out
  • Polar spots unlikely
  • Could be interstellar dust. Normally the dust is associated with gas but it could be that the dust and gas separate out on the small length scales involved in transits in front of the star and also the sodium lines are saturated - so you wouldn't notice any difference if there was extra neutral gas at the same relative velocity as the known clouds between the star and us.
  • The planet eating hypothesis ("post merger") is still viable
  • Intrinsic variability of the star has some support. Though it's not clear why it would be so rare that we only see one star like this in the Kepler sample.
  • Dust clouds around the star are still a possibility though it is hard to see how this idea can deal with the lack of an infrared excess, and with the presence of some fine dust which should get blown away quickly
  • The exocomet idea is hard to reconcile with the lack of gas
  • The dust could be created by collisions of dry asteroids far from the star
  • Finally the idea of a black hole accretion disk between us and the star remains a viable explanation. The lack of gas could be due to the gas freezing out onto the dust in that situation or because the debris disk leads to unusual abundance patterns.

Robert Walker (talk) 18:24, 19 January 2018 (UTC)[reply]

Robert, many thanks for this thoughtful post, and the link to Jason Wright's new paper. And the larger point (correct me if I am wrong) is that the lack of a spectral signature -- although Jason presents some possibilities for explaining this away -- remains as a key question, and in the absence of a solution to which, there remain around the card table (speaking metaphorically!) a number of viable hands. Synchronist (talk) 05:55, 20 January 2018 (UTC)[reply]
@Synchronist: @Darkfrog24: Yes that is a good summary. And this article is way out of date as it has not been updated in light of the recent research. I think it needs editing but it's quite a radical rewrite because they have learnt so much since this article was written. I think the old hypotheses need still to be mentioned because it is important for the reader to know they have either been dismissed or are now thought of as unlikely. I suggest that the lede would be top priority, as it does not mention the new research yet.
Here is a first attempt at a summary to add to the lede:
"There is strong evidence for dust from the reddening (blue light obscured more than red), no evidence of gas, and there continues to be no infrared excess, and it is definitely ont being obscured by anything opaque as that would reduce all the light equally. The dust is a mix of coarse and fine sub micron dust with the finer dust particularly puzzling as it would be blown away rapidly if close to a star."
How does that sound? Any comments? And - maybe trim part of the rest of the lede, though it is okay to have long ledes here in Wikipedia so we could just add that as an extra paragraph first if it's agreed it is okay. After deciding on what to do about the lede we could discuss how to deal with the rest of the article. Robert Walker (talk) 11:07, 20 January 2018 (UTC)[reply]
Robert, we are obviously here dancing around the possibility of eliminating intelligent alien activity as the cause of these dimmings; I deeply appreciate the sensitivity with which you have entered into said dance -- by focusing first on the lede -- and the opportunity you have thereby afforded the alienists among us to perform a "fire dance", arising like a phoenix from the ashes; and so what about this possibility: that we are dealing here with alien "smoke signals" or "sky writing", in which -- as opposed to a rigid and permanent occluding structure -- clouds of particles are periodically released and coaxed into shell-like configurations? Is this plausible from a physics standpoint, keeping in mind both the incredible difficulty -- and the incredible imperative! -- of communicating across interstellar space? I.e., are we in a position to rule out such a possibility, given the several holes in a purely natural explanation? Synchronist (talk) 07:43, 21 January 2018 (UTC)[reply]
Oh we can't rule out it being due to ETs yet, not until we know much more about it. It just seems more unlikely. But the ET hypothesis can explain almost any observation by assuming they use unusual materials or have unexpected objectives. E.g. the blue extinction could be because they have a design that lets red light through - and you need to try to think why they would do that. The lack of infrared excess could be because they beam the infrared away in some particular direction not towards us. Or because they use the collected sunlight to power giant lasers and not for conventional technology so that most of the energy collected is beamed away with a reasonably high efficiency.
If it is dust, well, one idea is that extra terrestrials might "lift material" from a star to create new structures or planets and this might lead to a lot of dust as a byproduct.
I'm not sure how much of this speculation is citable in wikipedia, as it would need to be from reliable sources e.g. publications in journals. But it is much discussed online. See for instance
* Your thoughts on dusty aliens and Dyson motes
* loose talk of #aliens
I like your alien "smoke rings" hypothesis and you might get some responses in those discussions. After all - something like this has indeed caught our attention - and it would any other extra terrestrial intelligence looking at the skies.
BTW there were several responses already to the post I made to that reddit about your dust question. It's had around 11 upvotes and is near the top of the list of topics for the reddit. One interesting suggestion I've never seen before - what if it is ice crystals from geysers, maybe from very large Centaur like objects that come close to the host star and produce Enceladus style geysers? The debris from those geysers that from the Saturn E ring is an almost perfect match for the size distribution they observed. Someone there has just posted suggesting that we could test for this hypothesis by looking for the absorption peaks due to water vapour or ice during a significant dimming. They say that with the Enceladus plumes they spotted a strong signal at 2.9 microns. [6]
As for mentioning this in the article, well there is that post by the astrophysicist recently discussed in the reddit: David Hogg - he tweeted: "I don't understand why the reddening of the Boyajian star is understood to "rule out" aliens. Who knows that much about aliens? I think it just "supports" the interstellar dust hypothesis." and wrote that thought provoking blog post they discussed on the reddit: loose talk of #aliens
I think it might possibly be enough of a WP:RS to be mentioned here, but we'd need to discuss this on the talk page first probably as it is somewhat grey area. But it is a tweet and blog post by a respected astrophysicist. Is it appropriate to use it here as a cite for a section on whether the aliens hypothesis is still viable? What else is needed to establish it as a suitable cite if not? Or what other type of a cite do we need to look for to add a section on this topic? Any thoughts anyone? Robert Walker (talk) 11:49, 21 January 2018 (UTC)[reply]
Hmmm! And maybe the long-term dimming -- if there in fact has been such -- is due to the "smoke rings" -- and these whether due to geysers (which seems highly plausible) or alien activity or whatever -- being continuously blown away from the star such that it is being shrouded in a permanent mantle? And note that my purpose in bringing up these possibilities -- and I think yours as well -- is not so much to suggest their specific inclusion in the article, but rather to maintain article quality by insuring that it continue to encompass potential such solutions. Synchronist (talk) 15:47, 21 January 2018 (UTC)[reply]
Yes indeed - yes that would be the idea. The fine ice dust would be constantly blown away but constantly replenished, from the interior of the icy worlds with their geysers. And yes that is my intent. I think it is an idea to keep an eye on such things, watch out for developments, and it helps to keep in mind these possibilities to make sure we don't say things in the article that close them off due to some misreading of the literature on the topic. Since experts are reading that reddit, it's always possible that one of them writes a paper on this if it does indeed have merit - and at that point it could be included here. Obviously at present it is not suitable. We can discuss it in more depth on reddit if necessary, if you want to take part in the discussion there, here of course our focus has to be on improving the quality of this article. Robert Walker (talk) 16:43, 21 January 2018 (UTC)[reply]

References

  1. ^ A Reassessment of Families of Solutions to the Puzzle of Boyajian's Star

The Big Picture

Can it be possible that we do not yet have a single plot that shows ALL of the dimmings to scale, and on a single time-line, from the first Kepler 20% "mega dimmings" to the more recent of approximately 1% range? Synchronist (talk) 06:36, 22 February 2018 (UTC)[reply]

Tabby's Star - Very Rough Draft of All Known Dimmings - From December 2009 to December 2017
 Done - @Synchronist: FWIW - a single plot of all known dimmings of Tabby's Star (December 2009 to December 2017) seems worth considering - my very, very rough draft effort is shown above if interested - a much better plotting is welcome of course - in any case - Enjoy! :) Drbogdan (talk) 17:50, 22 February 2018 (UTC)[reply]
Drbogdan, many thanks! Most informative! Synchronist (talk) 05:55, 23 February 2018 (UTC)[reply]
To be honest, this seems rather pointless, given that the Kepler graph used here is outdated. A 2016 re-analysis of the Kepler lightcurve has shown that KIC 8462852 Faded Throughout the Kepler Mission, rather than staying "flat" between dips. See also Figure 1.1 on Bruce Gary's archived page.Renerpho (talk) 01:57, 13 September 2018 (UTC)[reply]
The only reason the graph is flat is because the data has been filtered and normalised like all the Kepler lightcurves are when looking for transits. It isn't "outdated" per se, it's just one way to present the data. It depends what you want to show, if you just want to show the short-period variability then a normalised lightcurve is best, if you want to show all the modes of the stars' variability then a non-normalised version is better (but also less clear). ChiZeroOne (talk) 06:25, 13 September 2018 (UTC)[reply]

UPDATE: An updated consolidated plot of all known dimmings of "Tabby's star" has been created by "User:Synchronist", and has been added to the main article at "KIC 8462852#Light curve gallery" (replacing the earlier "Very Rough Draft" effort) - related comments/discussion at => "User talk:Drbogdan#Tabby's Star dimming data - consolidated plot" - further improvements to the plot/caption in the "KIC 8462852 main article" welcome of course - in any case - Enjoy! :) Drbogdan (talk) 12:49, 21 May 2019 (UTC)[reply]

Consolidated plot of all known dimmings (21 May 2019)

other strange stars.

there are 4 strange stars including this one , one is mention here as well the EPIC one , there is a 3 that i am still trying to refind and now a 4 called VVV-WIT-07 can some one make a page for this star and also mention it in the article?

1:KIC 8462852(Flickering Adult star)

2:EPIC 204278916(Flickering Proto star)

3:Przybylski’s Star (Adult star with material that you would only expect if a alien race would dump stuff into the star)

4:VVV-WIT-07 (Flickering ? star) [unsure for its stage] Joshoctober16 (talk) 20:59, 26 November 2018 (UTC)[reply]

If anyone is looking for articles to create, Google turns up plenty of sources for VVV-WIT-07 / VVV WIT 07 and we don't appear to have it yet. Alsee (talk) 21:50, 18 May 2019 (UTC)[reply]

FWIW - a listing of similar strange stars has been created, and may be found at => "List of stars that dim oddly" - hope this helps - iac - Enjoy! :) Drbogdan (talk) 14:03, 8 September 2019 (UTC)[reply]

Requested move 8 September 2019

KIC 8462852 → Tabby's Star – Per guidelines on commonly recognisable names for article titles. The following reputable sources either preference the use of "Tabby's Star" ahead of "KIC 8462852", or do not even use "KIC 8462852" at all, in their articles or media – Arizona State University [1], Astronomy magazine [2], BBC Science Focus [3], CNET [4], Cosmos magazine [5], EarthSky [6][7], Forbes [8], The Guardian [9], The Independent [10], the Jet Propulsion Laboratory [11], News.com.au [12], The Planetary Society [13], PBS's Nova [14], Science News [15], the SETI Institute [16][17], Sky & Telescope [18], and Space.com [19]. – PhilipTerryGraham (talk · articles · reviews) 08:21, 8 September 2019 (UTC)[reply]

@Synchronist: To answer your questions, 1) common names identified through informed consensus are given preference over official names, and 2) as Drbogdan has researched above, "Boyajian's Star" is used even less than "KIC 8462852" and "WTF star", so it is clearly not the common name here. It has nothing to do with paying tribute, moreso giving the article a clear name that people can recognise from sources, such as the ones I linked in my original proposal, that have discussed the star and referred to it by that name. – PhilipTerryGraham (talk · articles · reviews) 19:57, 9 September 2019 (UTC)[reply]
Your points are well taken, and with my goal having been to address the professional astronomers who have suggested "Boyajian's Star" as the official name. Synchronist (talk) 08:42, 10 September 2019 (UTC)[reply]
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