Does this cluster make my mass look fat?

By Phil Plait | February 3, 2010 11:19 am

What’s better than a gorgeously stunning image of a massive cluster surrounded by delicate, wispy nebulosity?

Well, nothing, really. Unless you can use it for SCIENCE!

[Click to gigantisize.]

Purty, ain’t it? That’s NGC 3603, a very large star-forming region in our own Milky Way Galaxy, lying about 20,000 light years away. It can only be seen from the southern hemisphere, which is why the European Southern Observatory folks got this image using the ginormous Very Large Telescope, an 8-meter behemoth in Chile (and actually, Ginormous Telescope would be a cool name).

Not too long ago — no more than a million years, give or take — a lot of the stars forming the central cluster there were born. There are so many that they appear to overlap, but that’s an illusion due to the blurring of the image from the Earth’s atmosphere (and the nature of light itself only allows us to make star images so small).

Lost in that crowd is a star designated NGC 3603 A1, and it is the most massive star to ever have its mass directly measured. It’s actually a binary star, two monsters locked in a gravitational dance, orbiting each other once every 3.77 days — which right away tells you this is a special pair, possessing enough gravity to toss themselves around that rapidly.

Using simple laws of physics discovered by Kepler back in the 1600s, we can measure the masses of each star in the duo. The heftier of the two is a whopping 116 times the mass of the Sun — which is close to the upper limit of what a star can get to without tearing itself apart. The more massive a star, the more luminous it is, and the surface can get so hot that any material there gets blown off… so that sets a lid on how big a star can get. Details vary depending on a lot of factors, but really 116 times the mass of the Sun is about as big as you’ll ever get for a star in our galaxy.

The other star in the binary is no slouch, tipping the scales at 89 solar masses. If it were just sitting out there all by itself it would rate as a phenomenal star, too. But its partner still wins the prize.

And how do I know those stars were born no more than a million years ago? Because massive stars don’t live long, and any beasts like these two live short lives indeed. It won’t be long before they detonate as supernovae, lighting up with a violence and fury that will make each outshine the rest of the stars in our entire galaxy combined!

Not only that, but pretty much every star you see in that cluster is of the massive and luminous classes astronomers call O and B stars, bruisers with enough oomph to explode as supernovae. How many stars do you see in that cluster? Dozens? So think about that: each one of those will become a titanic supernova, wreaking havoc across dozens of light years, sending out blasts of light to outshine galaxies, and throwing out octillions of tons of gas.

Eventually that gas, laced with heavier elements created in the nuclear forge of the supernova blast wave itself, will slam into, merge with, and seed the surrounding gas in the nebula. Compressed beyond its ability to sustain itself, the gas will collapse and form more stars. Some of these may be massive ones which will again repeat the cycle, and some will have lower mass, be fainter, cooler. They may form planets from those heavy elements. It will be a rocky birth, given the environment, but the vagaries of orbital dynamics dictate that eventually those systems will leave the nebula and move out on their own in the Milky Way. And a billion years from now, two, four billion, who knows what creatures may roam the surfaces of any of those worlds.

And will they see more stellar factories dotting the galaxies starscape, and wonder what their own looked like, all those eons ago?

CATEGORIZED UNDER: Astronomy, Pretty pictures, Science
MORE ABOUT: NGC 3603

Comments (53)

  1. Very cool and beautiful stuff. Glad that you included that max size tidbit. I did not know that stars had a limit.

    I also think that “Ginormous Telescope” would be a cool name. Maybe if two french siblings with the last name of Ginormou, would create one, we’d have it. :)

  2. Katharine

    Speaking of solar masses, this has totally screwed up my understanding of the Chandrasekhar limit. Explain please?

  3. I’m a little unclear about something. At one point you say “The heftier of the two is a whopping 116 times the mass of the Sun – which is close to the upper limit of what a star can get to without tearing itself apart.” 2 sentences on you say “Details vary depending on a lot of factors, but really 166 times the mass of the Sun is about as big as you’ll ever get for a star in our galaxy.”

    Is 166 the limit, and 116 is thus close to that limit, or are both those numbers supposed to be the same number, and the actual limit would be some unstated higher value? If they’re both supposed to be the same, which one is it – 116 or 166?

    Thanks for another interesting article!

  4. Daniel

    The Chandrasekhar limit is a measure how massive a white dwarf can be before it cannot sustain its electron degeneracy pressure and either collapses into a neutron star or explodes as a supernova type Ia

    The Chandrasekhar limit is roughly 1.44 solar masses.

  5. Minos

    Assuming the pair don’t go supernova at the same time by astonishing coincidence, what happens to the slower one when its partner explodes?

  6. AliCali

    What happens to the star that is only 89 solar masses when the one right next to it, at 116 solar masses, goes Supernova? Isn’t there a whole lot of energy being released? Will it shed off some of the mass of the 89 star? Or did I read about this in that Death book?

  7. Torbjörn Larsson, OM

    116 times the mass of the Sun — […] but really 166 times the mass of the Sun is about as big as you’ll ever get for a star in our galaxy.

    Um, slip of the finger? “Click [wrong key] to gigantisize”, perhaps?

  8. Hilary Mark Nelson (#4): yeah, that was a typo. :) I fixed it.

  9. Mark

    Reading this kind of stuff always just makes my jaw drop at the wonder of the Universe. It also makes me vaguely sad, though, that human lifetimes are so infinitesimally short that while we understand how all of these things work, we will never be able to actually witness the birth of a star, solar system, or galaxy. One could observe for many human lifetimes, and would still see only a snapshot of the actual processes in play. But still, wow.

  10. DrFlimmer

    I also vote for the name:

    “Ginormous Large Telescope”, or GLT for short.

    Sounds much better than “Extreamly large”.

    But this pair of stars is even more massive than Eta Carina. Holy crap! Interestingly more and more massive stars turn out to be double star systems. Maybe there is a rule to it… but why?
    And when do they blow up?

    Btw: Your post, Phil, is a much better read than the press release of ESO ;)

  11. mike burkhart

    This is spectlar just like all the other images on this blog as for a name for all Trekies out there how about calling it the mutara nebula (mention in Star Trek 2 the warth of Kahn , it became the Genesis Planet and thanks to Dr Marcuss use of protomater tore itslef apart in Star Trek 3 the search for Spock)

  12. mike burkhart

    By the way Phill you have’nt commineted on the science or bad science of the Genesis device in Star Trek (if you did I missed it ) this is another piece of neat tecnolgy that is common in Star Trek but I think it has some problems For one you would have to use it on a planet in a solar systems habital zone ( if I used it on say Jupiter the new planet would freze if I used on Mercury it would fry ) and of course you would have to find a planet that orbited a star like our sun a planet orbiting a red giant or a white drwaf would not be able to sustain life (a planet orbiting a neutron star,black hole or a black drawf out of the question) those are the major drawbacks I see may be Phill could name others

  13. TDL

    Best…blog title… evah!

  14. Daniel

    Great read! Almost poetic, though not quite – enough to keep me staring at my ceiling tonight wandering what distant ball of hydrogen might explode this evening, unknown to us.

    To answer your question, though – who knows what creatures will roam those worlds? Humans, of course – or at least our decedents. We will watch and wait as these tasty worlds form into something similar to what our ancestors grew up on, faintly trying to remember the times when surface gravity and atmospheric conditions were issues of concern. We will roam these planets and treat them as the intergalactic equivalent of protected national parks.

    At least, that’s what I think. Being optimistic, of course. ;)

  15. Why Dr. Plait, of course this doesn’t make your mass look big at all. I like your mass just the way it is!

    (Not that I have had any practice at evading a similar sounding question!) :D

  16. WJM

    Ginormous Telescope?

    Hells yeah.

    And remember, the write-in campaign for space shuttle Enterprise was a success…

  17. Farko

    How far apart are these two stars with a 3.77 days orbit period?

  18. This makes me wonder if anyone saw our solar system forming billions of years ago (or if someone is watching our solar system forming now; from billions of light years away).

  19. cbranch

    Looking closely at this pic, I have a question (I’m no astronomer, sorry if it’s a silly one) – why does it seem like there are so many stars, especially in the central region, that are “lined up” – three or more in a more or less straight line? I know: lots of stars, they’re bound to make patterns from some angle; it just seems there are more than I would expect from pure randomness. Is this just a human tendency to find patterns where there are none, or is it a real phenomenon deriving from the physics of star formation?

    Thanks!

  20. Lawrence

    I never understood why they had the go and make things complicated in Star Trek III by saying the Genesis device was unstable because of “protomatter” in the matrix (totally getting my geek on here) – when an easier and more plausible explanation would have been to say the GD was designed to work on existing planets & the fact it created an entirely new one from the nebula resulted in the instability.

    I know – I just reached a whole new level of nerd right there. Great article Phil – great pic too.

  21. RickK

    Preface this post with statement – I know VERY little about astronomy.

    The statement that a star with 116 solar masses is at the upper end of the spectrum surprised me. So I went back and looked at some examples. Sure enough, stars can be MUCH larger while not being that much more massive.

    I can see why a red giant would be large, but not dense.

    But what about a star like Rho Cassiopeia – it is a yellow star, with a radius that is 450 times that of Sol. If I understand it correctly, if Rho Cassiopeia were set down in the middle of our planets, its outer edge would be beyond the orbit of Mars. So it strikes me as surprising that it is only 40 solar masses.

    So I guess all supergiant stars, even the yellow and (presumably) blue varieties, have a lower density than our Sun. Interesting.

  22. RickK

    Preface this post with statement – I know VERY little about astronomy.

    The statement that a star with 116 solar masses is at the upper end of the spectrum surprised me. So I went back and looked at some examples. Sure enough, stars can be MUCH larger while not being that much more massive.

    I can see why a red giant would be large, but not dense.

    But what about a star like Rho Cassiopeia? It is a yellow star, with a radius that is 450 times that of Sol. If I understand it correctly, if Rho Cassiopeia were set down in the middle of our planets, its outer edge would be beyond the orbit of Mars. So it strikes me as surprising that it is only 40 solar masses.

    So I guess all supergiant stars, even the yellow and (presumably) blue varieties, have a lower density than our Sun. Interesting.

  23. Chris

    Awesome post Phil. Really enjoyed it the combination of a great picture, cool science and a fantastic story made it so fun to read.

  24. Jon Hanford

    Just a quick question, is NGC 3603 A1 the same star as Sher 25 (possible supernova progenitor just above NGC 3603 and between the two “greenish” nebulae)?

  25. DigitalAxis

    Just think, NGC3603 A1 will not live as long as the human race already has (including all variants of genus ‘homo’)

    I can’t find a link to any paper or press release ABOUT the star, which is odd.

  26. Jon Hanford (26): No, they’re different. I had actually written several paragraphs about Sher 25 before deciding the post was getting too long, so I’m planning on posting it later this week. :)

  27. Chris Winter

    I think if NGC 3603A1 goes supernova, it will be one hell of a show here on Earth. I mean, 20,000 LY distant — that’s not very far. Thinking back to Sn1987a, IIRC that was in the Small Magellanic Cloud about 170,000 LY off, and it was naked-eye visible.

    Beauteous image, BTW…

  28. scottb

    Looking closely, you can see many regions that look similar to the famous “Pillars of Creation”.

    Very cool.

  29. IVAN3MAN AT LARGE

    DigitalAxis:

    I can’t find a link to any paper or press release ABOUT the star, which is odd.

    You can find one here: The Very Massive Binary NGC3603-A1

    :cool:

  30. IVAN3MAN AT LARGE

    Phil Plait:

    I had actually written several paragraphs about Sher 25 before deciding the post was getting too long, so I’m planning on posting it later this week.

    Fer Sher?!

    :cool:

  31. Hi Phil, any idea how far these two stars are apart in order to be orbiting each other so fast? Such as compared to the scale of our solar system? A (very) quick search on the web didn’t provide any answers to that (though I must say I didn’t try very hard). The quick search did tell me (as an additional fact) that A1 is the first star to have been weighed and have exceeded 100 solar masses (83 solar masses being the biggest previously).

    BTW. I love the excitement, passion, and joy of your writing here!

  32. mike burkhart

    Lawrence welcome to the world of Star Trek I have watched it since I was 6 years old(I discoverd it when the animated series was on in the 70s an then watched reruns of the show)and I still don’t understand the tecobable thats used for example I never figured out the stardate system and I don’t think there was one I think they just used random numbers each time for stardates

  33. Al Viro

    @6,7: unless the envelope is dropped in apoastron of rather eccentric
    orbit, the pair is going to break (envelope goes away *fast*, so
    the momentum trasfer between it and remaining pair won’t be large;
    unless I’ve fscked up back-of-the-envelope math, for remaining pair
    in its c.m. system, you get kinetic energy/potential energy ratio
    grow by factor of old mass of system/new mass of system; time-averaged
    kinetic energy/time-averaged potential energy in bounded system
    is -1/2 and positive total energy => breakup; the total mass is going
    to decrease more than by factor of 2, so…)

    In any case, you are going to get a very fast neutron star and very
    fast normal star; they probably won’t stay together. With the pair
    that narrow I’d expect the original orbits to be near-circular, but
    IANAAstronomer and that’s pretty much a gut feeling. If it’s right
    *AND* if we can ignore the mass loss from the sucker swelling beyond
    its Roche lobe, the pair ought to break.

    If the mass loss happens on the scale of tens of M_sun, aforementioned
    back-of-the-envelope math seems to indicate that pair could stay
    bound. NFI whether it’s likely in that system – ask somebody who
    knows astrophysics. ~1e-2 year period with masses about 1e2M_sun
    would mean what, distance below 0.15ae? So some leak should happen,
    the question is what kind of rate would it be, what would it do
    to orbits, thermodynamics of the atmosphere and probably a bunch of
    other interesting stuff.

    Al, enjoying the “I’m 16 years past caring about the F I’d probably
    get for the above” moment…

  34. Levi in NY

    I really really hope I get to see a supernova in my lifetime.

  35. One of the bajillion joys of Hubble is that we can now see intense massive blue star-forming regions in other galaxies, like the Pinwheel and Whirlpool. As Phil says, most of these stars are so big and burning (fusing) so fast they will probly become supernovae. Hence, all of the 92 elements except 1-4. Mineral collectors like myself need these supernovae to create all the weird things we find on Earth, like Xenotime-Y.

  36. Messier Tidy Upper

    Great write-up there BA. Superluminous – ie. beyond just brilliant! 8)

    But some questions I’d really love to have answered :

    1) What are these stars precise spectral & luminositie classes please?

    O-something type hypergiants I presume right?

    2) How far apart are they in AU / equivalent orbit of Mercury / Venus etc .. & does this mean they will exchange matter as they evolve?

    3)How do they compare to Eta Carinae, the Pistol Star and another star massive star the BA blogged about a year or so ago?

    How well established are their masses and distances? Could they be multiple stars rather than apparently just two as has happened before with such objects as S Doradus?

    @ 24. RickK Says:

    Preface this post with statement – I know VERY little about astronomy. The statement that a star with 116 solar masses is at the upper end of the spectrum surprised me. So I went back and looked at some examples. Sure enough, stars can be MUCH larger while not being that much more massive. I can see why a red giant would be large, but not dense.

    Indeed true – the outer layers of Red supergiants have been described as “red hot vacuum” so – not-dense are they. (BTW. is there a word with the opposite meaning of dense in this sense?)

    But what about a star like Rho Cassiopeia? It is a yellow star, with a radius that is 450 times that of Sol. If I understand it correctly, if Rho Cassiopeia were set down in the middle of our planets, its outer edge would be beyond the orbit of Mars. So it strikes me as surprising that it is only 40 solar masses. So I guess all supergiant stars, even the yellow and (presumably) blue varieties, have a lower density than our Sun. Interesting.

    Stellar expert & author James Kaler has a great website which may be helpful here which I’d recomend along with his books if you haven’t seen it already :

    http://stars.astro.illinois.edu/sow/sowlist.html

    & fromthere more on Rho Cass. :

    http://stars.astro.illinois.edu/sow/rhocas.html

    I think your summary re; density is pretty much the case for supergiants of types M (red) to F (yellowwhite) but I’m not so sure about the “smaller” and much hotter and denser bklue supergiants from types A (white eg. Deneb) to O (Naos or Zeta Puppis) which I think – but am not 100% sure – may likely be much denser than our Sun.

    @ 3. Katharine Says:

    Speaking of solar masses, this has totally screwed up my understanding of the Chandrasekhar limit. Explain please?

    Wikipedia cna help you :

    http://en.wikipedia.org/wiki/Chandrasekhar_limit

  37. AbuMaia

    I just love the names science people give stuff… Very Large Array, Very Large Telescope, Big Bang, Black Hole, TGV (“Very Fast Train” in French, not spacey, but still techy). I find it very amusing how we have these people who can think in very technical ways about things, and yet somehow find a way to use the least possibly technical names for stuff.

  38. Messier Tidy Upper

    @ 7. AliCali Says:

    What happens to the star that is only 89 solar masses when the one right next to it, at 116 solar masses, goes Supernova? Isn’t there a whole lot of energy being released? Will it shed off some of the mass of the 89 star? Or did I read about this in that Death book?

    The star may be ejected by the blast and become a “runaway star” such as Zeta Ophiuchi :

    http://stars.astro.illinois.edu/sow/zetaoph.html

    Or it may remain bound to the black hole or neutron remnant of its partner and become a high mass X-ray binary system such as Cygnus X-1.

    http://stars.astro.illinois.edu/sow/cygx1.htm

    @ 36. Levi in NY Says:

    I really really hope I get to see a supernova in my lifetime.

    me too, man, me too! :-)

    Provided it is that they don’t explode *too* close or pose a slight threat of Gamma ray bursting like WR-104 or perhaps T Pyxidis.

    See : http://blogs.discovermagazine.com/badastronomy/2008/03/03/wr-104-a-nearby-gamma-ray-burst/
    &
    http://blogs.discovermagazine.com/badastronomy/2010/01/07/no-a-nearby-supernova-wont-wipe-us-out/
    &
    http://blogs.discovermagazine.com/badastronomy/2008/02/24/what-star-will-blow-up-next/

    Looks like our leading candidates are Eta Carinae, Betelgeux & now T Pyxidis although many other possibilities exist.

    @ 21. cbranch Says:

    Looking closely at this pic, I have a question (I’m no astronomer, sorry if it’s a silly one) – why does it seem like there are so many stars, especially in the central region, that are “lined up” – three or more in a more or less straight line? I know: lots of stars, they’re bound to make patterns from some angle; it just seems there are more than I would expect from pure randomness. Is this just a human tendency to find patterns where there are none, or is it a real phenomenon deriving from the physics of star formation? Thanks!

    I think that’s an illusion created by the pattern seeking human mind and the fact that we have a lot of stars crowded in together in this gargantuan star cluster / O-B stellar association. I don’t think there is any real physical cause or reason for this – but I may be wrong.

    Oh & no worries! ;-)

  39. Plutonium being from Pluto

    On potential supernova candidates this one is obscure but apparently ranks as potentially the most dangerous :

    http://jumk.de/astronomie/special-stars/hr-8210.shtml

    HR 8210 is a Delta Scuti variable star with a close-to-the-Chandrasekhar-limit white dwarf companiion which could go type Ia SN soonish or so this says.

    I’d guess WR-104 comes second with T Pyxidis and then Eta Carinae next on the “potentially hazardous to our health” supernova list but perhaps the BA or somebody else could elaborate further here?

    Antares, Rasalgethi (Alpha Herculis) & Mu Cepehi are other possible -but not dangerous – red supergiant supernova candidates that spring to mind along with Betelgeux which has been shrinking oddly of late & which has already triggered the odd false alarm incl. this one from me :

    http://www.bautforum.com/space-astronomy-questions-answers/93070-betelguex-much-brighter-than-usual-tonight-maybe.html

    (Mea culpa.)

    – StevoR

  40. StevoR

    Betelgeux which has been shrinking oddly of late

    I really thought that the BA had blogged on this discovery but despite searching here I couldn’t find Dr Plait’s item about it – but I did find (again) this source on that Betelgeusean shrinkage for y’all :

    http://www.newscientist.com/article/dn17282-betelgeuse-the-incredible-shrinking-star.html

    – Plutonium being from Pluto (a.k.a.StevoR)

    PS. Funny how talk of massive stars always quickly gets around to talk of supernova isn’t it? Not that there’s anything wrong with that! ;-)

  41. Asimov fan

    How do they compare to Eta Carinae, the Pistol Star and another star massive star the BA blogged about a year or so ago?

    Would that be the star A1 (small “name” for a big star!) a high mass binary star of 114 and 84 solar masses respectively which is located at the center of NGC 3603?

    The BA blog link is here:

    http://blogs.discovermagazine.com/badastronomy/2007/06/07/astronomers-find-most-massive-star-ever-discovered/

    & the discovery date was June 7th, 2007 if that’s of any help.

    From there you can also check out this great BA blog article :

    http://blogs.discovermagazine.com/badastronomy/2007/02/07/gamma-rays-from-monster-stars/

    which looks at another scarily high mass fiercesome star WR-20a in the Westerlund 2 star cluster which are emitting extreme X-rays from back inthe days when Fermi was GLAST.

    Another massive star binary which was once the record holder is Plaskett’s Star which y’all can read about here via Kaler’s site:

    http://stars.astro.illinois.edu/sow/plaskett.html

  42. Asimov fan

    Oops! Hang on I’ve just seen that this star *is* that star – A1 of NCG 3603! (Blushes.)

    So this is a refined mass estimate then? Upwards from 114 to 116 solar masses & its companion from 84 to 89 solar mass!

    So the Bad Astronomer has posted on it before – did he forget about that earlier post? Understandable if so I guess. ;-)

  43. Stanley H. Tweedle

    The word is ‘enlarge’ not gigantisize!

  44. Jacob

    @39. AbuMaia
    My favourite one of these is the scanner image aquisition software TWAIN, which stands for “Technology Without An Interesting Name”.

  45. Mark Hansen

    Oh look, QUASAR multi-name has reinvented him/herself as Stanley H. Tweedle. Unfortunately, still puts out nothing other than mindless pedantry in pointlessly embiggened font.

  46. Pi-needles

    @ 44. Stanley H. Tweedle Says:

    The word is ‘enlarge’ not gigantisize!

    Not here it isn’t. ;-)

    Like it or not, the BA has a habit of coining lots of alternatives to the word ‘enlarge.’ Its an old issue on this blog that’s been done to death ages ago & you won’t be changing it. I wouldn’t waste your fingers on it if I were you.

    @ 45. Jacob Says:

    @39. AbuMaia – My favourite one of these is the scanner image aquisition software TWAIN, which stands for “Technology Without An Interesting Name”.

    Hmm .. That seems to be self-contradictory / paradoxical! ;-)

  47. Pouria

    Question. Our sun, or even our whole solar system must’ve been the result of a giant star going supernova, giving us the heavier elements of which our little rock and ourselves are made from. Right?

    So to my question, has there been any research as to finding this supernova remnant? Shouldn’t it be relativly closeby (as in a few lightyears)? Or would it have dimmed long ago? Can it be found by its gravitational influence? Is the Alpha Centauri triple star system also the result of said supernova? Do we currently have the knowledge/skills/instruments to check this?

    /Pouria

  48. Chris Winter

    This is a fascinating question, sometimes touched on in science fiction: Piers Anthony’s Macroscope, for example.

    I am not an astronomer, even an amateur one. But consider the time interval. Our solar system is upwards of 4 billion years old. That’s about 16 orbits of galactic center. I doubt the motions of Milky Way stars are near well enough known to make answering your question possible. In the future, perhaps — but not today.

  49. Pouria

    Thanks Chris for shedding some light on this for me :)
    I actually did find some information about this at:
    http://www.solstation.com/stars/sol.htm

    So we on our way it seems.

    I know this post has already been long forgotten by most, but I figured I’d still post a suggestion here for Dr. Plait, incase he reads it.

    Is it possible for you to write up some posts every now and then about astronomy, that aren’t current events. Maybe let people throw around some questions in comments and you pick a few and answer them (for us non astronomer, but very interested people).

    I know alot of your posts already do this, educating the masses, but mostly it deals with current events, and unfinished research (which leads to alot of speculation, not a bad thing but still).

    You could call it Bad Astronomy 101 :)

    Regards
    Pouria

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