APOD: Hubble's Messier 5 (2014 Apr 25)

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APOD: Hubble's Messier 5 (2014 Apr 25)

Postby APOD Robot » Fri Apr 25, 2014 4:12 am

Image Hubble's Messier 5

Explanation: "Beautiful Nebula discovered between the Balance [Libra] & the Serpent [Serpens] ..." begins the description of the 5th entry in 18th century astronomer Charles Messier's famous catalog of nebulae and star clusters. Though it appeared to Messier to be fuzzy and round and without stars, Messier 5 (M5) is now known to be a globular star cluster, 100,000 stars or more, bound by gravity and packed into a region around 165 light-years in diameter. It lies some 25,000 light-years away. Roaming the halo of our galaxy, globular star clusters are ancient members of the Milky Way. M5 is one of the oldest globulars, its stars estimated to be nearly 13 billion years old. The beautiful star cluster is a popular target for Earthbound telescopes. Of course, deployed in low Earth orbit on April 25, 1990, the Hubble Space Telescope has also captured its own stunning close-up view that spans about 20 light-years near the central region of M5. Even close to its dense core at the left, the cluster's aging red and blue giant stars and rejuvenated blue stragglers stand out in yellow and blue hues in the sharp color image.

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Re: APOD: Hubble s Messier 5 (2014 Apr 25)

Postby saturno2 » Fri Apr 25, 2014 4:29 am

Beautiful image
Amazing, longevity stars
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Re: APOD: Hubble s Messier 5 (2014 Apr 25)

Postby Beyond » Fri Apr 25, 2014 4:35 am

Boy! I musta really been not paying attention. A lot of this space stuff that gets talked about, is right here in the confines of the Milky Way Galaxy and not 'off' somewhere else, like I been thinking, including today's APOD.
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Re: APOD: Hubble s Messier 5 (2014 Apr 25)

Postby Ann » Fri Apr 25, 2014 4:37 am

Nice! I'm glad to see a Hubble picture of a globular cluster that was made using three filters! Apart from the standard 606 nm and 814 nm filters, there was also a 390 nm near ultraviolet filter used for this image. That should bring out the hottest, bluest stars, and I tried to spot tiny blue dots that might be white dwarfs here. I think I may have seen three. Otherwise, these faint blue dots may have been extreme horizontal branch stars, but they seemed a bit too faint for that.

Several galaxies could also be seen right through the cluster, far behind the age-old stars of it.

Overall, a very nice picture!

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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Boomer12k » Fri Apr 25, 2014 5:29 am

Hubble never fails to impress...it always shows the vivid splendor of the heavens...


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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby starsurfer » Fri Apr 25, 2014 7:12 am

You can even see some background galaxies!
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby msadesign » Fri Apr 25, 2014 10:23 am

I wonder what the sky would look like from any planet…and given the incredible longevity I imagine spacefaring empires bridging short distances between stars…
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby semaj » Fri Apr 25, 2014 11:44 am

Ann, I am fan of APOD and have been reading the comment section for years. You are thoughtful, informative and always kind with your words. Who are you. I would be interested in reading a bio on you. In fact, it would be nice to know many of the regular contributors of Starship Asterisk*. I always look forward to the incisive dialogue of all. Thanks.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Joules » Fri Apr 25, 2014 11:58 am

Lovely! Made me check on exoplanets in Globular Clusters. Still none found. In open clusters, yes: http://www.universetoday.com/108127/thr ... r-cluster/
But still nothing from which to view globulars close up.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby BDanielMayfield » Fri Apr 25, 2014 12:24 pm

Joules wrote:Lovely! Made me check on exoplanets in Globular Clusters. Still none found. In open clusters, yes: http://www.universetoday.com/108127/thr ... r-cluster/
But still nothing from which to view globulars close up.

That shouldn't be surprising though Joules. Planet formation is a by product of star formation, and star formation currently takes place in open clusters.

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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby owlice » Fri Apr 25, 2014 12:35 pm

Stunning image!!!
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby 43221lynx » Fri Apr 25, 2014 1:06 pm

The link to "blue stragglers" states:

the two ways that blue stragglers — or "rejuvenated" stars — in globular clusters form. The upper illustration shows the collision model where two low-mass stars in an overcrowded environment experience a head-on collision, combining their fuel and mass and to form a single hot star. The lower illustration depicts the "vampire" model consisting of a pair of stars that undergo a transformation, with the lower-mass star draining its larger-mass companion of hydrogen that fuels its rebirth.


Two questions,

Why are the stragglers called stragglers?


How does a star with lower mass "drain" hydrogen from one of greater mass? Gravity can't do it can it? EM forces? How?
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby HAL 9000 » Fri Apr 25, 2014 2:22 pm

This cluster is 25,000 light years away from our galaxy. Can you just imagine the view of the milky way from there? And not only that, consider 100,000 stars in the space of a globe with a diameter of 165 light years. Cosmically speaking that's jam packed! Imagine the view from within the globular cluster. The sky would be filled with bright stars. Maybe there's no such thing as night there. Now my head's spinning... Over and out.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby geckzilla » Fri Apr 25, 2014 2:39 pm

HAL 9000 wrote:This cluster is 25,000 light years away from our galaxy. Can you just imagine the view of the milky way from there? And not only that, consider 100,000 stars in the space of a globe with a diameter of 165 light years. Cosmically speaking that's jam packed! Imagine the view from within the globular cluster. The sky would be filled with bright stars. Maybe there's no such thing as night there. Now my head's spinning... Over and out.


25,000 light years away from us, not the galaxy itself. There are probably some configurations that could make night like a permanent twilight but this discussion has been had before and apparently the human tendency is to overestimate how a star cluster would affect the night sky of such a hypothetical Earth-like planet within. The full moon is brighter than the stars would be and it doesn't eliminate night.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Ann » Fri Apr 25, 2014 3:53 pm

semaj wrote:Ann, I am fan of APOD and have been reading the comment section for years. You are thoughtful, informative and always kind with your words. Who are you. I would be interested in reading a bio on you. In fact, it would be nice to know many of the regular contributors of Starship Asterisk*. I always look forward to the incisive dialogue of all. Thanks.


Thank you so much, semaj!

The short answer is, I am a somewhat private person who has been interested in astronomy since I was fourteen. What really kindled my interest in astronomy was my realization that the universe is so inconceivably big. Understanding how this universe has come to be (if possible), trying to understand how it will evolve (and for me personally, hoping that we are not headed for a cosmic train wreck of a Big Crunch), savoring the incredible beauty of the universe (brought to us by fantastic telescopes and wonderful amateur astrophotographers) and understanding how the Earth, life on Earth and us humans in particular fit into the universe have been the questions and the motivating forces that have kept up my interest in this wonderful and in a way all-encompassing topic.

Again, thank you so much for your kind words!

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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Chris Peterson » Fri Apr 25, 2014 4:17 pm

msadesign wrote:I wonder what the sky would look like from any planet…and given the incredible longevity I imagine spacefaring empires bridging short distances between stars…

Stars in globular clusters are unlikely to have planetary systems that show long term orbital stability, so complex life may not develop in them.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Chris Peterson » Fri Apr 25, 2014 4:21 pm

43221lynx wrote:How does a star with lower mass "drain" hydrogen from one of greater mass? Gravity can't do it can it? EM forces? How?

Gravity. Keep in mind that the surface gravity of a compact low mass star can be much higher than the surface gravity of a large high mass star. So even a low mass star can strip material from the outer layer of a high mass star.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Chris Peterson » Fri Apr 25, 2014 4:23 pm

HAL 9000 wrote:This cluster is 25,000 light years away from our galaxy. Can you just imagine the view of the milky way from there? And not only that, consider 100,000 stars in the space of a globe with a diameter of 165 light years. Cosmically speaking that's jam packed! Imagine the view from within the globular cluster. The sky would be filled with bright stars. Maybe there's no such thing as night there. Now my head's spinning... Over and out.

The night sky would have many very bright stars. The view of the Milky Way would probably be unimpressive- more of a blob than the linear structure we see, and quite washed out by the bright local stars.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Ron-Astro Pharmacist » Fri Apr 25, 2014 4:39 pm

What a gem of an object to view! Fascinating that they "roam the halo of galaxies." Viewing the 'blue straggler' link it caught my eye that the rejuvenation process depicts older, tired stars roaming around then merging to form a blue giant. Reminded me of an old pair of stars "staggering" around in the neighborhood eventually finding a new address in which to settle down in to begin a new life. (Sounds like retirement with a twist) Wonder if they ever run into a round-about that they need to negotiate? Which eventually gets me to a point, "Do these clusters ever establish or reestablish angular momentum?" Or are halos a special area of galaxies that are immune to forces one might associate with a spherical structure under gravities effect. For example – Coriolis or Lense-Thirring effect if the stars generate a sufficient gravitomagnetic field.

Really only rhetorical questions to express how interesting I find our universe. Google does a good job of pointing us to the research being conducted.

http://arxiv.org/abs/1305.6025

Wish I could grasp the true complexity of such processes and articles. Thanks APOD for keeping the subject matter flowing!! You give us old guys and gals a chance at rejuvenation too. US - gray stragglers.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby geckzilla » Fri Apr 25, 2014 5:17 pm

Ron-Astro Pharmacist wrote:Wish I could grasp the true complexity of such processes and articles. Thanks APOD for keeping the subject matter flowing!! You give us old guys and gals a chance at rejuvenation too. US - gray stragglers.

You may not have seen this before. Just some useful tips.
How to read and understand a scientific paper: a guide for non-scientists
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Ann » Fri Apr 25, 2014 5:31 pm

43221lynx wrote:The link to "blue stragglers" states:

the two ways that blue stragglers — or "rejuvenated" stars — in globular clusters form. The upper illustration shows the collision model where two low-mass stars in an overcrowded environment experience a head-on collision, combining their fuel and mass and to form a single hot star. The lower illustration depicts the "vampire" model consisting of a pair of stars that undergo a transformation, with the lower-mass star draining its larger-mass companion of hydrogen that fuels its rebirth.


Two questions,

Why are the stragglers called stragglers?


How does a star with lower mass "drain" hydrogen from one of greater mass? Gravity can't do it can it? EM forces? How?


Good question. This wikipedia article will answer at least some of your questions.

Personally I'd like to call attention to the second brightest star in constellation Perseus, Algol. In the star chart on the left, the pink arrow points at Algol.

Algol is a double star - really a triple star, but that does not really concern us here. The two main components are a main sequence (hydrogen-fusing) blue star of spectral class B8V, and an orange giant of spectral class K or late G. The blue component is about ninety times brighter than the Sun. In order to be so bright and blue, a star has to be massive, and according to professor Jim Kaler, the blue component contains 3.4 times as much mass as the Sun.











But massive stars evolve fast. The more massive they are, the bluer they are when they are young, but the faster they evolve and leave their "blue youth" behind. Soon (say, after a few hundred million years or less), the blue star will have used up the hydrogen in its core. When that happens, the star will swell up and become a red giant. As a red giant, the star is very much bigger than before. Because the red giants are so big, they are also brighter than they were during their "main sequence youth". But because they are so big, they don't "hold on to" their outer layers as well as they did when they were younger and much more compact.

Albireo. Credit: Conrad Jung.




A more massive star is brighter in its youth than a less massive star. It will also run through its main sequence life time faster than a less massive star. As the more massive star swells up, turning into a red giant, it will become even brighter than before. Its less massive companion, by contrast, will still be a main sequence star by the time its more massive companion turns into a red giant. Therefore the smaller star will remain more or less as bright as it was before (for a time), and it will also maintain its color and temperature (for a time). Usually, when the more massive component of a binary pair swells up, you get an orange or a yellowish primary giant star and a bluish secondary main sequence star. A well-known example is Albireo.

But Algol is not like Albireo! The main sequence blue star is much brighter than the orange giant. The orange star is a bit bigger than the blue primary, but not by much at all - the radius of the blue star is 2.9 solar radii, and the orange star is 3.5 solar. And the blue star is by far the more massive of the two, 3.7 solar masses versus only 0.81 solar masses for the orange star.

Yet it is clear that the blue star is a main sequence star, which fuses hydrogen to helium in its core, whereas the orange star has already used up its core hydrogen. So how can the orange star be so small, faint and light-weight, then, when it ought to be gigantic, relatively massive and very bright?

This is what has happened. The two main components of Algol are close together. When the more massive component used up its core hydrogen and started to swell, its outer layers came too close to the more compact secondary star. The gravitational attraction from the smaller, compact star was now stronger than the gravitational attraction from the giant star. As the smaller star began to "eat" the outer layers of its giant companion, the small star became more massive. As it became more massive its gravity grew stronger, and it could capture even more of its swollen companion's outer layers. Eventually, the small companion had turned into a bright, blue, B-type main sequence star, even though it must have been smaller, fainter, more light-weight and yellower from the beginning. The giant, on the other hand, became terribly shrunken and emaciated.

This would be a way for blue stragglers to be created. Imagine two stars, one about as massive as the Sun and the other one less massive. After ten billion years or so, the solar mass star would swell into a red giant. But if its companion was close enough, it might capture the outer layers of the swollen giant. Eventually, this could lead to the small companion gaining so much mass that it turned into a blue straggler.

Blue stragglers are called stragglers because they are "lagging behind": they remain (relatively) blue and are found on the main sequence long after (almost) all other blue stars have used up their core hydrogen and turned into red giants or white dwarfs.

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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby Patrick60 » Fri Apr 25, 2014 5:38 pm

In the right of the image, just beside the small spiral galaxy there is what appears to be a red planetary nebula. However, this image is repeated through the picture in many other places. What would have caused such an artifact, or could it be gravitational lensing?
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby geckzilla » Fri Apr 25, 2014 5:46 pm

Patrick60 wrote:In the right of the image, just beside the small spiral galaxy there is what appears to be a red planetary nebula. However, this image is repeated through the picture in many other places. What would have caused such an artifact, or could it be gravitational lensing?

I knew someone would ask about those little red ghosts and last night I decided to investigate them. They're definitely artifacts of some sort but for once it's not very clear to me exactly how they were introduced. Anyway, if I find out more I will post it here but for now all I can say for sure is they aren't real. They're not nebulas or lensing.
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby 4321lynx » Fri Apr 25, 2014 5:52 pm

Thank you Ann :)
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Re: APOD: Hubble's Messier 5 (2014 Apr 25)

Postby BMAONE23 » Fri Apr 25, 2014 7:23 pm

geckzilla wrote:
Patrick60 wrote:In the right of the image, just beside the small spiral galaxy there is what appears to be a red planetary nebula. However, this image is repeated through the picture in many other places. What would have caused such an artifact, or could it be gravitational lensing?

I knew someone would ask about those little red ghosts and last night I decided to investigate them. They're definitely artifacts of some sort but for once it's not very clear to me exactly how they were introduced. Anyway, if I find out more I will post it here but for now all I can say for sure is they aren't real. They're not nebulas or lensing.

I would wager that they are image processing artifacts. They appear adjacent to all the larger redder stars and similarly oriented throughout the image. Also, I noticed that several of the blue stars along the left side of the image have a slightly offset grouping of red diffraction spikes, similar in color to the Ghost images (probably on the same color channel)
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