Astronomers see ANOTHER star ripped apart by a black hole!

By Phil Plait | May 2, 2012 2:03 pm

Last year, astronomers saw the violent death throes of a star as it was literally torn apart by a black hole (see here, and links within). And now, they’ve seen it again: observations across the electromagnetic spectrum caught another star that wandered too close to a supermassive black hole, and suffered the ultimate fate.

These observations show the before-and-after (left versus right) of the event. The top two are from GALEX, a satellite that observes the skies in the ultraviolet, and the bottom using Pan-STARRS1, a powerful telescope (located on which mountain, you ask? Why, Haleakala in Hawaii, of course) that scans the entire night sky looking for transients, things that change brightness.

The light from the star’s violent demise reached us in June of 2010. The event happened in the heart of a distant galaxy, 2.7 billion light years away. At the center of that galaxy is a black hole with millions of times the Sun’s mass, comparable to the black hole in the center of our own Milky Way galaxy. The star apparently orbited the black hole in an elliptical orbit. Over millions or billions of years, the star evolved, and turned into a red giant. Over time, its orbit tightened, and one day it got too close. The enormous tides of the black hole tore the star apart.

The flare happened when the stellar material spiraled into the hole. It formed a flattened disk right before the Ultimate Plunge, which got very hot and blasted out high-energy light — the ultraviolet light from this galaxy flared 350 times brighter than it was before! Some of the material from the star was also flung away into space. Astronomers put together a nifty video simulating what happened:

[You can watch a high-def version of this on the Hubble site.]

The material ejected was determined to be mostly helium, a sure sign that the star was old; stars start out mostly hydrogen, and slowly convert it to helium over time.

Events like this are rare; they probably only happen every 100,000 years or so per galaxy. So the astronomers looked at 100,000 galaxies, giving them good odds they’d see something like this once per year. Their gamble paid off.

In 2011 the Swift satellite saw a star that met a similar demise; Swift’s advantage is that it scans the sky rapidly and can view huge chunks of it at a time. This was probably the first time anything like that had been seen. It takes time to look over the data and make sure it’s not some other more normal event like a supernova or flare from a black hole as it eats a gas cloud.

Hmph. "Normal". Right. I guess compared to a star ripped to shreds by the ferocious gravity from a supermassive black hole, yeah, a supernova is pretty normal. What a way to go either way though!

Rare events are hard to witness unless you have a keen eye and watch the whole sky. The reason something this was never seen before is because it’s only with modern tech — bigger telescopes with digital detectors plus satellites tuned to different wavelengths of light — that we can see them at all. This was literally impossible to see even twenty years ago.

And our technology is getting better all the time! What other fantastically rare and über-violent events are going on out there in deep space, just waiting for us to see them?

Credit: NASA, S. Gezari (The Johns Hopkins University), A. Rest (STScI), and R. Chornock (Harvard-Smithsonian Center for Astrophysics)


Related Posts:

Astronomers may have witnessed a star torn apart by a black hole!
Followup on the star torn apart by a black hole: Hubble picture!
Star eaten by black hole still blasting away

Comments (52)

  1. Cindy

    Perfect timing as I’m about to cover the stellar endpoints in my Astro class. Nothing like a star being ripped to shreds to capture the attention of high school seniors in May.

  2. andyd

    What has actually been observed? A bright flash. What has been inferred? Everything in the article. What is actually known for sure? There was a bright flash.

  3. Chris

    Nom, nom, nom

  4. chris

    The simulation shows a star being ripped apart but the actual photos don’t show anything like that. what are we not seeing that allows the scientists to inferr what’s happening?

  5. Oh man, we just missed out on an excellent opportunity to open up a stable wormhole to the black hole via a circular bit of alien metal and generate endless energy! Or lose a never before mentioned former friend who we can bury the hatchet with right before they get sucked into the thing and then we blow it up. (The wormhole to the black hole, not the alien artifact, because that would totally kill the TV series. Also, said frenemy is never to be mentioned again)

  6. Dragonchild

    One thing I don’t understand. The Lorentz factor increases as matter approaches a black hole. The matter appears compressed, redshifts and time slows down, to the point where from our POV the matter gets “frozen” in time.

    Stellar gravity ain’t nuthin’ to sneeze at, so I’m thinking the “L” factor has to be pretty high before tidal forces tear apart the star.

    . . . so why can we observe it at all? Not only does the light take a long time to reach us, the star’s very approach appears “delayed” indefinitely.

  7. Dutch Railroader

    @Dragonchild

    The star gets ripped up long before it gets anywhere near the black hole in terms of frank relativistic effects. Our sun, for example, would have trouble getting within an AU of a 10^6 solar mass black hole, even though the horizon size is ~100X smaller…

  8. Chris A.

    @andyd (#2):
    Umm, you have heard of things called “spectra,” haven’t you? They reveal considerably more than simply “how bright.” (E.g. How do you think they were able to state that the dying star was mostly helium? Wild-a** guessing? Spectra can reveal composition, velocities, gas pressures, magnetic field strengths, rotation speeds, temperatures…)

    Of course, had you followed the link under the first image, you’d have known that, and could have avoided going off half-cocked. (For any others not inclined to follow the link, they did follow-up spectroscopy on this event with the MMT on Mt. Hopkins, AZ.)

    “Better to keep one’s mouth shut and be thought a fool than to open it and remove all doubt.”

  9. Cygnus-X1

    When I read stuff like this, I can only conclude that astrophysics has
    now reached the anthropology mode of analysis.

    “From examining the skull, anthropologists determined it belonged to
    a 12-year old girl who died April 23, 1284935 B.C. at 10:23 a.m. from a blow on
    the skull accidentally administered by the tribal shaman who had ingested too
    many hallucinogenic mushrooms and mistook her for an evil spirit.”

    In other words, drawing sweeping conclusions from limited data.

  10. Brian Too

    The change in visible + IR emitted is just a bit, um, underwhelming. Good thing they have the UV spectra to go on!

  11. Scott

    #2 andyd: You might wish to look up “spectrum”, as it pertains to analyzing astronomical data.

  12. josie

    andyd, Phil left out a lot of technical details about the way the science is effected.

    Just like police forensics can determine how an automobile crash played out by looking at the scene, scientists can get a pretty good idea of what happened by looking at evidence.

  13. Korr

    andyd, Exactly!

    This is what passes for “science” nowadays. Instead of the scientific method just pick your favorite theory and see how you can fit the evidence to your preconceived ideas.

  14. andyd (2), CygnusX-1 (9), and Korr (13): What you read: only what I wrote. What embedded links you clicked: apparently none.

    Maybe there’s more science and analysis to this story than what I wrote. If you clicked a link or two you’d find that out.

    But you go ahead and make up stuff about the way science is performed while not noticing the irony of how unscientific your statements are.

  15. andyd

    I did not make any unscientific statements. I was really wondering why you didn’t give a laymen’s interpretation of how they inferred all that. I’m sure a lot of people would appreciate that.

  16. Andrew

    “andyd, Exactly!

    This is what passes for “science” nowadays. Instead of the scientific method just pick your favorite theory and see how you can fit the evidence to your preconceived ideas.”

    The irony in this sentence is so strong I’m not sure whether to laugh in amusement or cry in despair at the current state of our educational system.

  17. Andrew

    andyd… if you are under the impression that the links in this article are NOT intended for laymen, you really have a lot of reading and knowledge to catch up on. 99% of the people (myself included) reading this page would not gain anything from a true scientific paper on the subject.. which is why this article and the ones it links to ARE intended for laymen..

    It would be like asking “well, I understand that gravity causes objects with mass to be attracted to each other, but whats the LAYMAN explanation for gravity?” (Hint – that WAS the layman explanation…)

  18. Jon Hanford

    For those interested in the details of the multiwavelength observations of this event, a preprint of the paper in Nature is available here: http://hubblesite.org/pubinfo/pdf/2012/18/pdf.pdf

    [Oh, and we do know a bit more than ‘There was a bright flash’. :) ]

  19. HvP

    andyd,

    No, you implied that the bright flash didn’t constitute enough evidence to infer this type of scenario.

    In fact, the article on the team’s findings show that direct evidence observed from merely this flash of light includes:

    1) a large volume of helium and very little hydrogen, which doesn’t correspond to the makeup of this galaxy’s interstellar gas but does correspond to a large mature star that has had its atmosphere ripped away…
    2) a very high temperature and speed of gas flow which points toward gas coming from a supernova or black hole torus…
    3) a rate of brightening that happened over much longer than a supernova would…
    4) the team was already studying galactic centers because flares of this type constitute the evidence that can confirm predictions already made about what happens when a massive black hole consumes a star, and this event matched those predictions.

    To quote Gezari, “You can’t find gas like that lying around near the center of a galaxy. It’s processed gas that has to have come from a stellar core. There’s nothing about this event that could be easily explained by any other phenomenon.”

    And all of that is just in the public release for lay audiences. The Nature paper is available online through the Hubble website if you wish to prepare a rebuttal.

  20. Titan

    So is this a quasar?

  21. HvP

    Titan,

    A quasar is somewhat similar to this event but with much much more matter involved. This event involved only a single star falling into the black hole in the galactic core. Otherwise, the core black hole is not actively feeding because there are no large concentrations of free gas funneling into the center.

    An active galactic core is feeding on massive quantities of interstellar gas, perhaps many light years wide, not individual stars. This causes a nearly continuous jet of energy to be expelled into space at the poles of the rotation. If the jet of energy is aimed at us then we can see it across many billions of light years as it outshines its host galaxy. Because we could see the core emissions but not the host galaxy is why we didn’t understand what they were at the time the term quasar was coined (Quasi-Stellar-Radio source.) Since then we’ve discovered nearer galaxies with actively feeding cores emanating jets of energy at an angle from our perspective and were able to connect the pieces.

    It doesn’t appear that the accretion disk that formed from this star was dense enough to form the intense energies indicative of quasars.

  22. daniel

    if this happened 2.7 billion light years away… how long ago (in our time measurement) did this happen? I’m unable to find an answer using google and am not smart enough to work it out!

  23. Jeff

    Wow. I’m surprised stellar spectra garnered the same “what do scientist know” reactions that your evolution/vaccine/climate change articles normally do.
    It may only be a blip going from reddish to whitish, but people really need to consider what it is we’re seeing. I guess if the star dying in a super massive black hole at the center of a galaxy 2.7 billion years away isn’t like CGI, then we’re too jaded to be impressed by this discovery…

  24. Cygnus-X1

    > andyd (2), CygnusX-1 (9), and Korr (13): What you read: only what I wrote. What
    > embedded links you clicked: apparently none.

    Don’t make assumptions. Although the Nature paper is behind a paywall, it is also posted on astro-ph at http://arxiv.org/pdf/1205.0252.pdf, and at http://hubblesite.org/pubinfo/pdf/2012/18/pdf.pdf, and I have a copy of it and have read it.

    While I agree the spectrum is consistent with a helium rich object with a very low Hydrogen mass fraction, and that the light curve differs from type Ia or type II supernova, the conclusion that the object fell into a black hole is at best an indirect inference from what you can determine from the data collected; and in fact was derived from numerical simulations and modeling as stated in the paper. Also, the derived integrated energy emitted of 2.1 X 10^51 ergs is consistent with a supernova.

    What I object to is that the conclusion is presented in this blog entry, and in the other articles in the popular press, and even in the NASA press release, as solid, unquestionable fact, when in actuality the conclusion is an interpretation of the data, but not the only one possible.

  25. Wzrd1

    That does it! I need to get some serious time on the 10KM trans-kuiper telescope! Now, THAT would be resolution.
    Or should that be 1000KM… ;)

  26. beedogs

    Lots of damned ignoramuses in this comment section. Holy crap. Some of you need to go read a book or twenty.

  27. Pineal

    The star wasn’t torn apart by the black hole, it was the black hole. It ran out of adequate fuel and burnt out, creating the black hole and sucking its information through it to be sent out the other side where that data will create a new galaxy over billions of years. Duhhhhh.

  28. andyd

    I just thought it was a very lazy posting by the BA. I had hoped for a lot more on the how what where and why. If he was just posting the same sort of stuff as the others then why bother.

  29. Khelben

    What I’m wondering is what the effects are if this were to happen in our galaxy. What effect it will have (with bandwith of different star types, orientation etc) for our solar system.

  30. Hugo Schmidt

    And people think we biologist are twisted when we get all excited over finding a new, cool disease.

  31. DaveK

    I had a moment of vertigo in that sentence where you wrote “2.7 billion light years away”.

    Because you italicised “billion”.

    To make clear that it was a lot. Something big.

    As if the fact that they were ALREADY LIGHT FRIGGIN’ YEARS IN THE FIRST PLACE wasn’t even significant!

    Like I said, vertigo. I felt small and insignificant. For a moment there I had a sense of proportion. Of perspective.

    Now, where’s that piece of fairy cake?

  32. Stan9fromouterspace

    Sorry, I know Phil’s Prime Directive is to be nice, but on this thread I can’t help but notice that idiot trolls are idiots. Phil was a bit more tolerant. Sorry to contribute such negativity.

  33. ND

    Cygnus-X1: “In other words, drawing sweeping conclusions from limited data.”

    Isn’t that what you just did by only readying what Phil wrote? Please read the original paper and tell us its scientific deficiencies in detail. Thanks.

  34. Seleuco

    Excuse me for my ignorance but I have a simple question I hope can easily be answered. If the light of this event has reached us in 2010, why is it only now being published, and even after the event observed one year later in March 2011?
    My guess is that only now has the data collected been decoded and thus the conclusion was reached, but I’d appreciate some clarifying!

  35. Cygnus-X! (25): You are correct, and my apologies; I shouldn’t have lumped you in with the other two. IMO andyd had an antiscience agenda by posting that comment, not bothering to delve any deeper than what I wrote, but your own angle was not necessarily the same.

    You are right of course that there can be other explanations. That’s always true. However, in this case, the long decay time, the power of the beam, and the presence of helium make this scenario seem far more likely to me than any others. It is at the very least consistent with a star getting torn apart, and I think the evidence makes it very likely. That’s why I wrote it the way I did.

  36. ND

    Cygnus-X1,

    Looks like your comment was in moderation when I posted mine. What other hypothesis do you have?

  37. Wzrd1

    We should get to see a singularity having a light meal of gas starting next summer. As I recall, Sag A* has a gas cloud that is rapidly heading toward it, that was the last predicted time frame for the edge of the cloud to reach the event horizon (or at least the accretion disk).
    That one should be a nice “light show”!

  38. Kellic

    Huh so that is what an Obama vs. Romney debate is going to look like. Good to know.

  39. Bill Nettles

    Cygnus-X1 said: “What I object to is that the conclusion is presented in this blog entry, and in the other articles in the popular press, and even in the NASA press release, as solid, unquestionable fact, when in actuality the conclusion is an interpretation of the data, but not the only one possible.”

    Anyone who paid attention in a decent science class know this, and anyone who actually accepts this interpretation (or any extrapolated) as “solid, unquestionable fact” doesn’t understand how science is done. As a science area progresses, there are maturing models and discarded models and infant models. We hope our models are accurate expressions of what is really happening (yes, I’m assuming that reality exists, and most scientists do … if they don’t, why are they doing science?)

    If the data works in the maturing models, that’s what gets the most attention. The infant models have to prove themselves as better, and answering data that the mature models does AND doesn’t. That was the problem with the Copernican model: it wasn’t BETTER than Ptolemaic, and that’s why Kepler succeeded (with the help of Tycho’s better data). Kepler’s model solved the problem of Mars, then continued to answer the behavior of Venusian phases and Jupiter’s large moons.

    If you have a model for the data (judging by your pen name, you either love or hate black hole models), crunch the numbers and publish it.

  40. Dave C

    bit of background, I’m 64, with a grade 12 education, (took a dumbed down 4 yr stream, rather than work at getting into University the harder 5 yr stream, my BIG MISTAKE!!!) but I am a reader, and thanks to that I know a bit more than the average educated person;
    when I read Phillips articles I bring that further education to the effort; I don’t just make off the cuff, uneducated remarks; so I “read” into them a wealth of information that isn’t included; or interpret them with a lot more than is visible on the written page; someone who like Andy and the others make disparaging remarks from a basis of ignorance, or sci-fi broad humour meant to be taken half seriously, don’t deserve to be replied to; if you don’t have the wit to understand the basic foundation of the subject, you shouldn’t be commenting on this thread or any other; I DIDN’T need to be told that they used Spectral imaging to determine the constituent properties of the light, it was a given that I didn’t need to think about;
    2.7 Billion years, in a Universe that is 13.X billion years old, is just on the other side of town ;) what is so surprising about that???

    @22. HvP
    Thanks for that explanation on Quasars, that is one that I hadn’t come across; there is so much information out here now, it is like being at a Chinese Buffet, 24/7 and it is hard to be selective when your like me, interested in EVERYTHING, from Paleontology to Pre-History Archaeology, Rocketry and Humanity as Space Faring Species and everything in between BWS; who needs politics, wars and religion, when there is so much more to discover; this fall I am starting a self directed course on Quantum Physics courtesy of Yale University; with any luck I’ll be around in 30 years to see more change ;)

    I am glad I lived to see this day, my parents would have loved it ;) I can only say to Andy, his friends, and cohorts, get a thirst and hunger for knowledge and dig in; you don’t have to be Stephen Hawking to appreciate the finer things in this smorgasbord; just be selective in the people you follow, and confirm their CV ;) a good saying to live by, Trust, but verify!

  41. By the way, Here is a finder chart for the Black Hole that swallowed the Red Giant. It’s near the USNO star marked in red, in Camelopardalis.
    Which is good, because NOTHING EVER HAPPENS in Camelopardalis…
    ;^)

    http://www.flickr.com/photos/24473498@N02/6993427106/sizes/l/in/photostream/

  42. Jim Johnson

    Phil, you probably get this sort of question all the time, but I wasn’t able to figure it out myself from my sources (Google). What could we expect to experience when next a star is pulled apart by the Milky Way’s supermassive black hole (if we’re still here when it happens)?

    When I read, “… the ultraviolet light from this galaxy flared 350 times brighter than it was before!” the question popped into my head.

    I figured I could just find out how much ultraviolet light reaches earth from our own galaxy (the sun excluded) & multiply that by 350, and have a ballpark answer – which I expected to still be far below the the threshold received from our sun.

    However, I haven’t been able to find how much ultraviolet light does reach us from the Milky Way. Some sites do provide info on how much starlight (which I assume to mean light in the visible spectrum) reaches earth, from which my calculations – bear in mind that my math is prone to mistakes – show that if such an event produced VISIBLE light 350 times brighter than the whole galaxy and it was not blocked by anything, then it would be about 7 % of the moon’s brightness by the time it reached us.

    However, even if the source & my math are both correct, that calculation makes several assumptions that I haven’t been able to verify, besides which I haven’t been able to find out what percentage of total starlight hitting earth is from within our galaxy, whether the 350X multiplier is anything close to representative, or if the star-ripping events emit light at other spectrums than ultraviolet. Even if correct, it doesn’t tell ALL the effects we’d witness in such an event, so finally I gave up and came here to ask the question.

    My guess was that the answer would be something like “the event would be detectable in the infrared but hidden in the visible spectrum and ultraviolet by the dust at the center of our galaxy”, but then I went back & re-read your posts from the earlier event, found this line, “It literally makes the hair on the back of my neck stand up. I’m glad this happened billions of light years away.”, and now I don’t know what to guess. But I’m still curious.

  43. Carl Coker

    Jim, your first guess would be correct. I don’t remember the exact number off the top of my head, but there’s somewhere north of 30 magnitudes of extinction in visible and UV light towards the galactic center. What this means is that if you presume the flare would be as bright as Sirius is in our sky if it were to occur in the MW (so, if it appeared as -1.5 visible mag) without all the dust and stuff in the way, it would be about 29th magnitude in reality, or about a trillion times fainter. You would see quite a bit of IR, radio, and X-ray, but the visible and UV light would be almost totally obscured.

    Just as a quick calculation, though, the absolute visible magnitude of the MW is -20 or so. 350 times brighter would make it -26 or -27. So, add on the 30 magnitudes of extinction I mentioned, and that comes out to about 3rd or 4th magnitude, but that’s still at only 10 parsecs away (32.6 light years). If instead we put it at the galactic center, ~8.5 kiloparsecs away, that drops to 17th or 18th magnitude, which is pretty faint. The apparent IR emission would be much brighter, since there’s much less extinction in the IR, but still not anywhere near enough to affect us in the slightest.

  44. Excellent article, again. I hope the day will soon come when we’ll be able to go beyond the dogma that nothing can escape a black hole. Black hole energy jets are well documented as travelling well beyond the gravitational pull of the black holes that produce them, originally being pulled in from their accretion discs. I have not read my latter point of view anywhere but I think it’s self evident

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