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Space Science

Monster Hypergiant Star Discovered 94

astroengine writes "A gargantuan star, measuring 1,300 times the size of our sun, has been uncovered 12,000 light-years from Earth — it is one of the ten biggest stars known to exist in our galaxy. The yellow hypergiant even dwarfs the famous stellar heavyweight Betelgeuse by 50 percent. While its hulking mass may be impressive, astronomers have also realized that HR 5171 is a double star with a smaller stellar sibling physically touching the surface of the larger star as they orbit one another. 'The new observations also showed that this star has a very close binary partner, which was a real surprise,' said Olivier Chesneau, of the Observatoire de la Côte d'Azur in Nice, France. 'The two stars are so close that they touch and the whole system resembles a gigantic peanut.'"
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Monster Hypergiant Star Discovered

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  • by jfdavis668 ( 1414919 ) on Wednesday March 12, 2014 @03:24PM (#46467251)
    and explode.
  • size? (Score:5, Insightful)

    by BradMajors ( 995624 ) on Wednesday March 12, 2014 @03:26PM (#46467271)

    Is it 1,300 times as massive, has 1,300 times the volume, or what?

    • by ceoyoyo ( 59147 )

      1300 times as massive.

      • Re:size? (Score:5, Informative)

        by luna69 ( 529007 ) * on Wednesday March 12, 2014 @03:40PM (#46467453)

        > 1300 times as massive.

        No. Original paper says ~39 Msun. Radius is ~1300. A star massing 1300 Msun couldn't hold itself together, both in terms of gravitational and outward radiation pressure.
        Source: http://arxiv.org/pdf/1401.2628... [arxiv.org]

        • That's for the system.

          Could an astronomer explain the \( 39_{--22}^{+40} \) notation? Seems a pretty big error margin, but I can't tell if it means "between 17 and 79 solar masses" or "between 22 and 40 solar masses"?

          • Re:size? (Score:5, Informative)

            by reverseengineer ( 580922 ) on Wednesday March 12, 2014 @05:50PM (#46468849)

            The 22 and 40 look like lower and upper bounds. In section 6.1 of the paper, it says, "we infer the lowest current mass of the system to be 22±5 [solar masses]" . They mention this value comes from a calculation based on Kepler's 3rd law. So it looks like the lower bound comes from orbital mechanics based on the orbit of the companion star and the upper bound of 40 comes from their interferometry observations and modeling of that data, but they consider it more likely that the true value is closer to the higher value.

          • From the paper, it looks like that is a confidence interval - see the first full paragraph on page 12. I think it means that the most likely estimate is 39M, and with some confidence they put the range at 22M to 40M.
        • A gargantuan star, measuring 1,300 times the size of our sun

          At 39M , It is certain that it is going to end up in a spectacular black hole .

          • I think this star would be a good candidate to end with an "un nova" and go straight to a black hole instead of exploding.

    • Better info at ESO (Score:3, Informative)

      by Bl4d3 ( 697638 )
      1,300 times the diameter apparently -> http://www.eso.org/public/news... [eso.org]
    • Size: implies volume.

      However, the article's author throws around massive and mass as if they are also measuring the mass of the star "50% more massive than heavyweight Betelgeuse" - I don't think the actual astronomers are talking about mass...

      • However, the article's author throws around massive and mass as if they are also measuring the mass of the star "50% more massive than heavyweight Betelgeuse" - I don't think the actual astronomers are talking about mass...

        Astronomers almost always measure stars by mass, both because it's more informative - mass determines things like fusion rate and lifespan - and because volume of a star is both hard to measure from distance and not really well defined, since stars are made of gas and thus don't have a w

        • V = 4/3 r cubed...

          1300x diameter = 1300x radius.

          1300 cubed is 2,200,000,000 - isn't it?

        • Correct, with decades of measurements it was estimated to be about 40 solar masses, but now that is being revised thanks to the smaller star.

          It is shedding lots of mass and is not very compact, and appears to be fluctuating internally and exploding externally. It is likely near the end of its life. So the outer shell appears to be 1315 times the diameter of Sol, but coming in at 40 Msun most of that is probably fairly sparse.

          Note that "end of its life" for a star is a really long time. At that size their

          • by kesuki ( 321456 )

            you do realize interstellar transport is impossible right? even if you use atomic metals to power it it would take roughly a third the power of the largest atomic bomb to accelerate 1 kilogram of mass http://www.scienceforums.net/topic/34180-energy-needed-to-reach-99-c/ [scienceforums.net]. to accelerate and then decelerate from light speed is unrealistic. not to mention the problem of needing working force fields, as hitting anything is the same as a http://en.wikipedia.org/wiki/Relativistic_kill_vehicle [wikipedia.org] without force shields

            • you do realize interstellar transport is impossible right?

              Not at all. In fact, we had all the tools for interstellar travel decades ago. It will take a long, long, long time for our machines to reach another star, but they have more than sufficient escape velocity and nothing between them and their eventual destinations.

              Your other links are based on rules set up by special relativity. Many people assume physics stopped at Newtonian physics in the 17th century, or they stop at Einstein's theories which are over a century old.

              Physics has come quite a long way sin

              • by kesuki ( 321456 )

                you seem to be under the impression that space is a hard vacuum it is not, modern observatories including space ones have hinted that there is a lot of space dust that hasn't coalesced into larger bodies. there are a lot of small, medium, and large space debris in the way. without a force shield even if the warp drive disintegrates the small stuff a pool ball sized debris is going to be rather like an atomic blast no force shield no ftl travel. and if people are going onboard they are going to have to do s

        • and because volume of a star is both hard to measure from distance and not really well defined, since stars are made of gas and thus don't have a well-defined surface.

          Also, this star (at about 2 197 000 000 [google.com] times the volume of the sun, but only at most ~39 times the mass) must have an extremely low specific density. AFAICT even the average density is very close to what we would call a vacuum here on Earth at 7.87 × 10^-5 kg / m^3 [google.com], and the mass is not evenly distributed, making it even more sparse for most of its volume.

          This surprises me a little, did I make any mistakes?

    • by Anonymous Coward

      Is it 1,300 times as massive, has 1,300 times the volume, or what?

      This is why I like slashdot... that was my first thought too. Most other sites you'd be left wondering, or *gasp* have to RTFA (with the risk that it, as per usual, has no additional info)

  • by KiloByte ( 825081 ) on Wednesday March 12, 2014 @03:27PM (#46467285)

    Saying that these stars touch each other is like saying Jupiter's diameter is comes at some random point within its atmosphere. Both include a large amount of very sparse gas, with boundaries being fuzzy.

    • Re:It's mere gas (Score:5, Informative)

      by JoeMerchant ( 803320 ) on Wednesday March 12, 2014 @03:31PM (#46467353)

      The photosphere is a pretty clearly defined boundary.

      If you want to go all "stellar windy" on the sun, it extends out beyond Pluto.

      • DUDE! (Score:5, Funny)

        by DarthVain ( 724186 ) on Wednesday March 12, 2014 @04:07PM (#46467777)

        Everything is connected man, everything!


    • If you stare at a double sun...do you go blind in both eyes or just one eye twice as fast?

  • by beheaderaswp ( 549877 ) * on Wednesday March 12, 2014 @03:28PM (#46467307)

    That binary system is going to make one heck of a supernova at some point in the distant future.

    Hopefully someone in cosmology will figure out what the energy release would be.

    Very very cool!

    • Very very cool!

      I'm sure you meant very very hot! ;)

    • Re:Awesome!! (Score:5, Informative)

      by Frobnicator ( 565869 ) on Wednesday March 12, 2014 @05:39PM (#46468747) Journal

      That binary system is going to make one heck of a supernova at some point in the distant future.

      Maybe, probably not, but there is not enough data to know. It's been over four hundred years since the last recorded supernova in the Milky Way, and telescopes weren't that great in 1604. (Also the standard note about time and distance in astronomy, the star's light we see today is from about 12,000 years in our past. We cannot see today, we see the past.)

      There is not enough data to say what will happen, and there are only a few major options for a star that size: partial collapse, full collapse, or ablation.

      It might go through a series of partial collapses, with many small contractions end up ejecting huge chunks of the star, then re-expanding, and themselves re-exploding on their way out. This seems to be a fairly normal end-of-life pattern. Basically the core works like a fireworks launch platform as we see in summertime displays. Eventually the remaining core might be collapsed or not, but the show will be enjoyable. The result is a small nebula.

      It might collapse into a neutron star. It might even collapse to a black hole. Either of these collapses MIGHT lead to a supernova, or maybe even a hypernova, or have a bunch of gamma bursts, or, most boring, nothing much at all; it just collapses with a (relatively mild compared to supernova) explosion and the outer layers blow away. Modern astronomers never seen it happen up close, so everything is a guess. Now that the partner is known people might be able to make a better guess, but it is still a guess. Depending on when it explodes, if ever, it will likely form a big nebula.

      The actual article says the larger star is rapidly shedding mass. If it is throwing enough mass out fast enough (which will be affected by its binary partner) it will shrink enough to avoid a core collapse. In that case it will throw out a bunch of mass and in a few centuries appear as a small nebula.

      But again we don't know what will happen because there are no similar data points. If you are looking for nearby stars to go supernova, there is a short list of known supernova candidates [wikipedia.org] that we can watch. Otherwise the supernova we see are from distant galaxies where we can only speculate about.

    • Another interesting question is whether the companion will survive the explosion, be ejected from the system, and have stripped off enough mass to go supernova itself some day. Potentially a high velocity supernova!
    • by geekoid ( 135745 )

      hopefully it will have happened 12,000 years ago, tomorrow

  • HTF does that work? (Score:2, Interesting)

    by Anonymous Coward

    The smaller part isn't "in orbit" in the traditional sense otherwise drag would pull it in. It's more like an asteroid that's too small for gravity to collapse it into a sphere, yet this thing is *just the opposite* in terms of size. The only thing I can think of is that the system must have absolutely stupendous spin and angular momentum. Either that, or there's a careful balance between the force pulling it in, and the heat pushing it away. That's more amazing to me than the size. How long can a syst

    • by Anonymous Coward

      Plainly it's stable enough for humans to emerge and observe it

      You realize that only means it had to be stable for a few (60 or so) years at most, right? (ie: from the first observation done of that star to the most recent.) I'm sure real astronomers would have a better idea about the likelyhood, but it's entirely possible that it only formed a few years before the first observation was made. "enough for humans to emerge" implies that it must have been around longer than humans have, but there really isn't any need for that. We could just be really lucky, and caugh

  • by Blaskowicz ( 634489 ) on Wednesday March 12, 2014 @03:40PM (#46467457)

    A giant ribbon was found in our neighborhood, only one link away, said researchers. It is one of the ten tallest ribbons or panels found on the web, being nearly 100 pixels tall. The ribbon's purpose seems to provide useful links and social "features", but we couldn't investigate much of this. The ribbon is unmovable even when you scroll the webpage, and its considerable height causes a gravitational lensing effect called "reading through a mail slot". Amazingly, a smaller rectangle was spotted nearby, it reads "feedback". It actually touches with your scrollbar! The whole result looks "modern" and slightly big, but scientists are puzzled that it feels so readable and non-annoying. Apparently, many other websites including previous submissions to slashdot were much worse.

  • I've had enough, first the click farmers, and now Planters© peanuts!

    Wait...maybe I'm just hungry.

  • So we're going to have astronomers shuffling around humming "Found a peanut"?

    Gah! Shoot me now!

  • I immediately check the Celestia Motherlode.

    The reason being that you can almost get a sense of how big something really is with it since it displays your distance to it in au (or ly, Kpc, Mpc).

    I encourage you to try it, hit H then G to go to sol, then scroll away first to 1 au, then 10, etc. The sun is still quite bright at 1 ly.

    Imagine how big that thing appears at 1 ly distance! // Maybe someone will create a Celestia add-on for it? Please please please!

  • I always find things out there in our galaxy like this pretty interesting. I never would have thought that something like this would be possible. I would think that they would have collided and merge or even just exploded.
  • so big.. and we're only finding it now?

  • by mythosaz ( 572040 ) on Wednesday March 12, 2014 @04:45PM (#46468167)

    http://en.wikipedia.org/wiki/L... [wikipedia.org]

    Seems to crack, maybe, the top-20.

    Some fascinating objects on that list...

  • Followed the link, "click[ed] to enlarge" and it's just a bright dot :(

  • That's not really another star, he's just REALLY happy to see us see him seeing us.
  • That's no moon!
  • Just think of all the fold points it must have.
  • "By analysing data on the star’s varying brightness, using observations from other observatories, the astronomers confirmed the object to be an eclipsing binary system where the smaller component passes in front and behind the larger one as it orbits. In this case HR 5171 A is orbited by its companion star every 1300 days."

    Wouldn't atmospheric drag from the Yellow Giant slow the companion star down rapidly or is it somehow "star surfing"?

  • From TFA:

    Although it’s located moderately far from Earth, HR 5171 can just about be seen on a clear night in the constellation of Centaurus with the naked eye and has been measured to have a magnitude of between 6.10 and 7.30.

    So, the title "Monster Hypergiant Star Discovered" is a little exaggerated. "Observations reveal new information about hypergiant star" would be better. Then again, it is the Discovery Channel who put this on their website. Maybe we should just be happy they don't express the size of the star in terms of football fields, and the volume in terms of schoolbuses.

  • Has a cousin from that star system, and he said the stars were just rubbish....
  • I wonder if this is the metal poor ( low Z > 4) halo star reported recently? Also, is this an evolved binary system where the outer layers of the secondary have accreted on the primary making it metastable? Some different equillibrium of a metal-poor star might be allowed in this condition than would be possible with large stars approaching solar metalicity.

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