Hubble’s Early Festivities: Imaging the M13 Globular Cluster “Snow Globe”

Article written: 8 Dec , 2008
Updated: 24 Dec , 2015
by

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This image is one of the latest views from the Hubble Space Telescope, closely resembling a toy snow globe. In this case, over a hundred thousand glittering stars are the little faux snow flakes and the cluster’s globular structure is the glass sides. The cluster of interest is M13, located over 25,000 light years away, measuring 150 light years across (that’s 0.15% the diameter of our galaxy). Although very pretty (and very festive), there are some interesting things going on inside this little cluster of stars…

The Empire Strikes Back. Globular clusters impart their wisdom to astronomers. Well, the connection was there for me anyway...

Yoda imparts his wisdom to Luke in Star Wars: The Empire Strikes Back. Globular clusters impart their wisdom to astronomers. Well, the connection was there for me anyway...

Globular clusters are very common, and many are known to surround our Milky Way galaxy. Over 150 ‘small’ clusters have been observed in our galaxy’s halo acting like cosmic artefacts; the stars contained within clusters like M13 are thought to be amongst the oldest known in the Universe. These clusters in the Milky Way halo are thought to have formed well before any stars existed in today’s Milky Way spiral disk. So these small, old clusters have some wisdom to impart on today’s astronomers as to the ancient history of our galaxy (why does Yoda from Star Wars spring to mind?).

The stars within M13 are predominantly old red giants that have expanded well beyond their original diameters and cooled significantly. These stars are stuck, gravitationally bound, orbiting a common point in the centre of the cluster’s mass. However, occasionally, as the centre of M13 is so densely packed, the old stars can stray too close, colliding, and creating a new type of star known as a “blue straggler”.

Blue stragglers appear off the main sequence of the Hertzsprung-Russell diagram (source)

Blue stragglers appear off the main sequence of the Hertzsprung-Russell diagram (source)

Blue stragglers are formed when the gas from one star is siphoned off by another. This rejuvenates one of the stars, heating it up significantly. This phenomenon has mystified astronomers for a long time as young, blue stars were observed hiding inside clusters of old, red stars. Only recently has this collision mechanism been put forward as a possible explanation to the appearance of “young”, hot stars inside globular clusters like M13.

Putting snow globes, Yoda and blue stragglers to one side, the stunning image at the top of this post comprises of several archival observations from Hubble’s Wide Field Planetary Camera 2 and Advanced Camera for Surveys. Four separate campaigns from November 1999, April 2000, August 2005 and April 2006 were used.

What a great picture to start getting into the Christmas holiday spirit with

Source: Space.com


22 Responses

  1. Jorge says

    If this cluster isn’t dubbed the “Jewelbox Cluster”, it should.

  2. Astrofiend says

    Jorge Says:
    December 8th, 2008 at 6:23 pm

    “If this cluster isn’t dubbed the “Jewelbox Cluster”, it should.”

    Unfortunately, there is already a Jewelbox cluster, located in the constellation of Crux in the southern hemisphere sky. It got the name from Sir John Herschel who described it as ‘a casket of variously coloured precious stones’.

    I guess that it got the name because through a smallish telescope, there are a number of brilliant and differently coloured stars visible. M13 looks a bit more monochrome through small scopes, but I agree – in a photo, M13 would much more aptly be named the Jewelbox cluster!

    Beautiful image.

    P.S. Ian – nice wanton Star Wars association!

  3. Silver Thread says

    You know, it’s just a hunch mind you, but I think most astronomers like to look at stars because of the science and wisdom they impart, but rather, because they are freaking beautiful.

  4. Salacious B. Crumb says

    M13, is nice globular, but compared to Omega Centauri and 47 Tucanae it appears as a mere pip-squeak.
    If you think this looks like a Jewel Box, well it has basically three colours. Methinks it looks more like a box of diamonds.
    As to the statement “Globular clusters are very common, and many are known to surround our Milky Way galaxy.” is a misnomer. Compared to the open clusters there are only 160-odd of them, with our galaxy probably topping 200. As there as so few of the it is a hard to sample the historical nature of globulars. I.e. Many of the expected long-term gravitational behaviours over the aeons remains sadly lacking in direct evidence. Globulars are more like jellyfish – pulsing by expanding and contracting over millions of years.

    Also the generalised statement; “However, occasionally, as the centre of M13 is so densely packed, the old stars can stray too close, colliding, and creating a new type of star known as a “blue straggler”. Still remains a theory on blue straggler origins. Probability of two stars colliding is still deemed to be remote. Blue stragglers could also be created by merging close binary stars, etc.

    Agreed. A pretty picture though…

  5. Bosco says

    Someone has seen Return of the Jedi one to many times.

  6. Mr. Obvious says

    SalaciousB… do you ever make a comment which isn’t antagonistic?
    You should at least read the article and comments a bit more closely. Nobody ever said the origin of B-Strags was absolute.

    Only recently has this collision mechanism been put forward as a possible explanation to the appearance…

    As with many things (if not most) the origins are our best educated guess. Quit being so negative, and you may learn to enjoy astronomy.

  7. TMo says

    Has anyone ever heard the theories about this cluster in regards to the possibility that ET may be living there due to the close proximity of the stars, the fact that stars have been known to migrate to the cluster, and the fact that we sent a signal specifically to this cluster?

    I was watching National Geographic’s journey to the edge of the universe and it kinda freaked me out and made me think and then look into this idea a little more.

    Any thoughts or comments?

  8. Salacious B. Crumb says

    Mr. Obvious said; “SalaciousBā€¦ do you ever make a comment which isn’t antagonistic?”

    Basically, No.
    However, even slight inaccuracies in some media stories often need some correction r clarification. In this case it is the conflicting statements. I.e.

    “However, occasionally, as the centre of M13 is so densely packed, the old stars can stray too close, colliding, and creating a new type of star known as a “blue straggler”. (Absolute statement, I think.)

    Against what you’ve quoted”;

    ‘Only recently has this collision mechanism been put forward as a possible explanation to the appearanceā€¦” (which isn’t)

    Both statements seemingly contradict one another. Also
    “Only recently”, is also a bit misleading as stellar collisions explaining the origins of “blue stragglers” have been first fully discussed by W.H. McCrea in the 1964 – 44 and a bit years ago. The first specific observations of blue stragglers was by Hiltner et.al in 1958 observing the globular NGC 6633, followed by NGC 6475 in 1959. (This is about 50 years ago.)

    My single point is the only other likely explanation is mergers of close binary systems.

    To quote Niolay Andronov, from his 2005 paper “Evolution of close binary stars with application to cataclysmic variables and blue stragglers”, that;

    “The predicted number of blue stragglers from main sequence mergers alone is comparable to the number observed in globular clusters. A population of subturnoff mergers of order 3-4% of the upper main sequence population is also predicted for stars older than 4 Gyr, which is roughly comparable to the small population of highly…depleted halo dwarfs.”

    Pedantic I might be, but and least I pretend I might know what I’m talking about.

  9. Mr. Obvious says

    Pretend is correct. Since you can only pull up others research, and not your own. Thank goodness for Google, eh.

  10. Mark says

    Here’s a question I left back in the Omega Centuri thread a few days ago … could anyone answer it for me? Thanks

    “Back of the envelope calcs on the numbers given in the article say that in the central regions of the cluster the stars are very close together – comparable to the distances that the planets in our solar system are to the sun (or each other). This kind of environment would play havoc on any orbits that the stars might try to have, so instead of orbiting they should just be free falling towards each other and towards the overall center of mass of the cluster. How are they going to survive very long at all in that kind of environment? The cluster is supposed to be almost as old as the universe (the article says 12 billion years old), during that time many cycles of star formation and supernova and then reformation are supposed to have occurred through gravity. Why doesn’t gravity compactify the whole shebang in that amount of time?”

  11. joe says

    Image how the sky would look if you were standing on a planet orbiting a star in a cluster.

  12. skweegee says

    FYI Bosco: the Star Wars picture is from Empire Strikes Back.

  13. Geoff says

    “The cluster of interest is M13, located over 25,000 light years away, measuring 150 light years across”.
    Galactic objects are described commonly with only a distance away from Earth, surely to be meaningful and general direction would also be useful. In this case M13 could be about 2500 light years away from the centre – or about 52500 light years away – if it were on a radial from the centre through the Earth; or anywhere on a circle 25,000 light years in radius. Using Asimov’s Foundation novels as a fanciful reality this could be near ‘Stars End’ or ‘Trantor’.
    Having seen general diagrams of the Milky Way galactic layout, perhaps an annotated (arrow – ‘you are here’ style) location of where these objects are located relative to the centre and/or Earth would be nice!
    Hope this is a useful comment!

  14. Salacious B. Crumb says

    Mr. Obvious Said
    “Pretend is correct. Since you can only pull up others research, and not your own. Thank goodness for Google, eh”

    Firstly, “irony” is actually spelt with an “i”.

    Also your statement is not actually correct. A much better source than Google is the Astrophysical Data Service (ADS).

    As for quoting “others research.” Actually, nearly all new science is based on the overall principle, often attributed to Isaac Newton :- Pigmaei gigantum humeris impositi plusquam ipsi gigantes vident (If I have seen a little further it is by standing on the shoulders of Giants.)

    It is not, as you quite wrongly say “As with many things (if not most) the origins are our best educated guess.” Learning and increasing our knowledge about science is actually based on empirical evidence, prediction and refinement of theory. “Best educated guesses” is NOT actually the basis science.

    As to your contributions on my comments on “blue stragglers”… I thank you.

  15. john says

    You find jewells whenever you look for them, in the right places, of course. The photo is a nice christmas gift. Enjoy the beauty.

  16. IKE:) the Alien lifeform says

    I like the never ending discourses:) between the 2 carbon copies, named Mr. Ob(li)vious;) and Salacious B. Crumb. Very enjoyable indeed, haha

  17. ruf says

    Do you know where to find a larger pic of the HR diagram shown in the article? The source has nearly the same sized pic. The text is a little small for my old eyes…

  18. Ken says

    Salacious B…Nothing worse than an ill informed grasp of science, coupled with in inherent sense of self, can describe what you wrote. I could flame you with facts, but please….I ASSURE you! If u had anything of value to add…You would have a blog and any human might look to you…But to troll and feel self important…

    Google my name etc etc…I NEVER respond/post etc…I troll and read…throwing out “stuff” but considering all…I looked you up and…YOU are obnoxious and ignorant. Wasting bandwidth (“Wasting” should be with lower case “w” there…dahhh..)

    I have yet to see you mentioned anywhere let alone:

    “Ahh, Salacious B..PLease educate me…your friend, Roy Booth (A real Astronomer)…

    Please add real content not minutia that makes you think you sound more educated than my 5th grader…Everywhere I went looking for something I found you “SPOUTING”….And it was all NONSENSE, self serveing etc…Go tell your wife…ooppss sorry…your next store neighbor how smart u r,.

    (I left the spell (ing) errors etc on purpose…)

    Please let people exchange ideas etc….If u were ANY good…Someone would pay for your stupid attacks on people informing the others and us asking one another concepts…

    PLEASE shut up…State the fact that someone has the mind to envision “blue Strag..”. You are the worst kind of moron. And yes U R A MORON!!

    To the other I am sorry.

    Sorry to take your time here.

    Sorry for going off topic. SORRY SORRY SORRY.

    I enjoyed the comment “Jewel box” why not….”Hey we already have jewel box down south (I’ve seen it”)….Honest question, honest answer…

    I like exchange and challenge…But if we are to honor ’09 IAD etc…If we are to encourage other to join our pursuit…further ideas and concepts..

    I have finally have my fill of SAlcious A55…He is everywhere with “It is not a tree mind u…in MY research ( i have a dime store looking glass like Galileo and thought I saw the moon..it was my crack…I have found trees to be wood or PULP…”.

    You can tell an AS5 when the “argument” starts to “U speelled this wrong and missed a comma…AND my elementary teachier (oopss missed th I there) always told my dumb newdull (get it NEW Dull…otherwise spelled Noodle..cuz we don’t have spell check etc)….

    Last sentence…and you won’t see me again…

    Sally….Shut up with your stupid 1/2 educated, moronic, insipid, remarks on others/statement of facts u don’t know/ and MOST DEFINITELY reference to others of “googling their internet machine” for research…If most of us were “Researchin” we wouldn’t be looking here…

    Again my SINCERE apologies to the others…I just couldn’t hold me tougnue one more second.

    Ken

    ps: Salicious D…don’t respond to me…I am not to return here…This is the 3RD PLACE I LEFT BECAUSE OF YOUR MORONIC NEGATIVITY…U can say sorry to the people you have so unabashedly offendded with your wit and wisdom…AS5!

  19. Ken says

    JOE, I said I was done here…..But my 2 cents worth…I had the exact same thought….I wish with all the CGI they would make a clip to show what we would see…How cool is that?!?!

    Sal…This is the kind of thought provoking concept we should be sharing.

  20. neophite says

    Hi what a fascinating thing!!! My only experiences are tilting my head upward, marveling at the majestic evening sky and pressing my nose to the window of a plane in high altitude night time flight. How astonishing that stars gather like this, initially I thought the sphere was a result of the snapshot from the telescope. Nearly inconceivable that these ‘snowglobe’ clusters exist.

  21. Ray Kent says

    Referring to the Hubble photo of M13. PLEASE settle an argument:

    Is the Photo showing such a perfect sphere ( snow globe ) as it was seen against the darkness of space …

    or is the perfect sphere …

    ( with some “bumps” of light representing individual stars along the margins ) …

    a result of the natural “cropping” by the cylinder housing of the telescope ?

    ie. a snapshot through the ring of the tube?

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