Tag: star formation

Ceci *est* une pipe

By Phil Plait | September 20, 2012 7:00 am

Oh, have I got a treat for you today. Behold the brain-busting beauty of Barnard 59!

[Click to ennicotianatabacumenate – and seriously, do it! – or stick the gargantuan 16,000 x 15,000 pixel version (!!) into your pipe and smoke it.]

This incredible picture was taken by the MPG/ESO 2.2-metre telescope at the European Southern Observatory’s La Silla Observatory in Chile. The chunk of sky shown in this image is pretty big for a deep sky photo – about 6 arcminutes on a side. For comparison, the Moon is about 30 arcminutes across, so we’re still talking just a teeny region. But look at all those stars!

Of course, it’s not the stars that draw your attention: it’s the not stars. This region of the sky, in the constellation Ophiuchus, is toward the center of the galaxy, and is lousy with gas and dust – the latter of which is actually composed of complex chains of molecules. These form grains astronomers call dust, though they’re not like the bunnies you find under your dresser: these are more like particles of smoke in size. Ethereally thin by earthly standards, they form clouds that are still so large, light years across, that they are effectively opaque. They block the light coming from stars behind them, so in rich star fields like this one the dust clouds are made visible by their silhouettes.

What you’re seeing here is one particular complex of dust in the much larger cloud called the Pipe Nebula. The picture inset here shows the whole thing, and the reason for the name is obvious. Barnard 59, seen in incredible detail above, is the mouthpiece of the pipe.

You really need to take a look at at least the medium resolution image. You can see tendrils, wisps, and many other features. One of the neat things that you might miss at first is how the dark clouds change the colors of stars behind them. Start in the center of the cloud, then look near the edge, where the cloud starts to thin out, and you can see stars once again. See how the stars along the edge are redder than the stars farther out? Dust scatters blue light – a blue photon sent straight at us by a star can hit a dust grain and be sent off in another direction, missing us. There’s enough dust at the edge of the cloud to do that.

But toward the center of the cloud we’re through a lot more of that floating junk, so much that it absorbs the light coming from behind it. This effect is called interstellar extinction, and it’s kind of a pain when you’re trying to look at stuff through a cloud. However, it does make for a very pretty effect in pictures like this.

One more thing. See those fuzzy stars in the center of the cloud? Those are stars being born right before your eyes! These clouds can have very dense, cold clumps of material which can collapse to form stars. Usually invisible to optical telescopes – these ones are on the near side of the dust cloud, which is why we can see them at all – they glow brightly in infrared, and telescopes that can see out past the visible part of the spectrum see these very clearly. And yeah, you really want to click that link. It’s eerie and beautiful and spectacular.

All of this is another reason I love astronomy. One person’s meat is another person’s poison. If you want to study stars, dark nebulae are a pain. But if you want to study how stars form, they’re the first place you want to look!

Image credit: ESO; ESO/Yuri Beletsky

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CATEGORIZED UNDER: Astronomy, Pretty pictures, Top Post

Cold fire threads Orion's Belt

By Phil Plait | May 2, 2012 6:00 am

Orion is the gift that keeps on giving. When you look toward that constellation in the sky, you’re facing a region of massive ongoing star formation. A sprawling cloud of gas and dust occupies Orion’s midsection, most of it thick and opaque. Some of it is illuminated by stars embedded inside, and some by the reflected light of nearby stars.

M78 is a section of the cloud just above Orion’s Belt that’s evidence of the latter. But even then, much of the dust is dark to our eyes. But if you look in the far, far infrared, where warm material glows, a different — and spectacular — view appears:

[Click to blackbodyenate, or grab the 2300 x 3500 pixel version.]

This is actually a combination of two views: one in visible light from the Digitized Sky Survey, and the other from the APEX telescope, which can see light in the submillimeter wavelength range — 1000 times the wavelength the human eye can see. Only cold, cold objects emit at this wavelength, things a few degrees above absolute zero.

The blue material in the image is gas and dust reflecting starlight from nearby blue stars, so it can be seen in visible light. The cold dust, though, threads in front and behind the visible material, and can only be seen by APEX’s eye, tuned as it is to the far infrared. Falsely colored in this image, it glows an eerie orange like fire running through cracks in the nebula.

But it turns out the cracks are the fire itself…

Read More

CATEGORIZED UNDER: Astronomy, Pretty pictures
MORE ABOUT: APEX, dust, M78, Orion, star formation

A red nursery with a long smoke stack

By Phil Plait | April 27, 2012 6:48 am

Something like 6000 light years away, roughly toward the downtown area of our galaxy, lies NGC 6604, a tight cluster of young, massive, hot, bright stars. Just starting to shrug off the gas cloud of its birth, these stars emit a fierce light that makes the gas glow. When you point the 2.2 meter ESO/MPG telescope at this cluster what you get is startling beauty:

[Click to ennebulenate, or grab the cosmic 8600 x 8400 pixel version.]

NGC 6604 is the compact group of bright blue stars in the upper left. This whole complex of gas (called Sharpless 2-54) is about 200 – 250 light years across, making it rather huge! You’re only seeing a fraction of it here, though. It’s actually part of an even larger series of nebulae which include the more famous Eagle nebula (the Pillars of Creation) and the Omega nebula.

The image is a composite of pictures from different filters. Ultraviolet and blue filtered images were combined to make blue in this image; green filtered light is colored green, yellowish light from nitrogen is yellow, and the red is actually red from warm hydrogen. As you can see, hydrogen is plentiful in this area!

Also, see those odd diagonal features on the lower left? Those extend for a long way, well outside the frame here. That structure is called a "chimney", and may be 650 light years long! As stars are born, they can blow massive winds from their surfaces. This puts pressure on the surround gas, and if there’s a weak spot — where the gas is less dense, or if it’s near the edge of the cloud — the winds can push through. It’s not clear exactly how these form, or why they tend to be so straight. It’s suspected magnetic fields are involved, but that complicates things hugely. Still, the chimney in Sharpless 2-54 is the closest one known (of dozens), providing a nice clear view of it. If we ever do figure out the detail mechanics of chimneys, no doubt this one will play a role.

Image credit: ESO

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CATEGORIZED UNDER: Astronomy, Pretty pictures

Desktop Project Part 26: Carina will keelhaul your brain

By Phil Plait | April 20, 2012 6:35 am

[The Desktop Project is my way of forcing myself to write a post about the astronomical images I’ve been saving to my computer’s desktop and then ignoring. I’ve been posting one every day for nearly a month, and this, my friends, is it. The last one. And I saved it for this occasion, because it’s ridiculously awesome. Thanks for bearing with me as I did this bit of housecleaning.]

The constellation Carina is a mess. It represents the keel of a ship, but in the sky it happens to be in the direction of the disk of our galaxy, which is like having a window in a building facing downtown in a busy city. And like an urban center, the Milky Way in that direction is lousy with gas, dust, stars… and much of this is chaotic, disturbed, and, well, messy.

Oh, but what a glorious, glorious mess. Behold! The Carina Nebula!

[Click to ennebulenate, or grab this ridiculously huge 13,000 x 9000 pixel monster version. And yes, you very, very much want to make this bigger.]

Holy wow! I love this image! It’s got it all: stars of every color studding a riotous background of gas, itself glowing red or reflecting blue, silhouetted in great ostentatious sweeps of dust. Shock waves riddle the gas, compressing it here and there in arc, loops, streamers, and filaments.

It’s ridiculous, and spectacular.

The image was taken using the HAWK-1 detector on the European Southern Observatory’s Very Large Telescope. This is an infrared picture, using colors outside what the human eye can detect. In the picture, what you see as blue is actually light at 1.25 microns, green at 1.65, and red at 2.2 microns. For comparison, the reddest color the eye can see is about 0.7 microns. Amazingly, in visible light this region is even more chaotic looking.

The Carina Nebula is about 7500 light years away, and is the site of a lot of star formation. Many of the stars being born are very massive, which makes them hot, blue, and frighteningly luminous. See that bright star in the lower left? That’s Eta Carina, one of the most massive stars in the galaxy. To give you an idea of how stupid violent and unstable that star is, in 1843 it erupted in an explosive event that rivaled a supernova. The star held together, barely, but it ejected two lobes of matter that have about as much mass as the Sun. Each. And they’re expanding at 700 km/sec (400 miles per second), fast enough to cross the continental United States in 12 seconds.

And one day Eta Car will explode. It’s too far away to hurt us, but what a sight that’ll be! And even now, just sitting there not exploding, it still shines about 4 million times brighter than the Sun. Four million. If the Earth were as close to Eta Car as we are to the Sun, we’d be vaporized into an ionized memory.

The HAWK-1 image is actually high enough resolution to get a lot of detail. Here’s a collection of nine interesting regions:

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CATEGORIZED UNDER: Astronomy, Pretty pictures

A stunning star factory for Hubble's 22nd!

By Phil Plait | April 17, 2012 11:59 am

April 24th marks the 22nd anniversary of Hubble’s launch into space. To celebrate it, NASA and ESA released this devastating panoramic view (also available here) of the mighty star-forming region 30 Doradus:

Yegads. [Click to embiggen, or get the 4000 x 3200 pixel version, or grab the ginormous 267 Mb 20,323 x 16,259 pixel version. There’s also a way cool zoomable image too.]

30 Dor is a vast, sprawling, and chaotic region located in the Large Magellanic Cloud, a dwarf irregular galaxy that orbits our Milky Way. Even though it’s about 170,000 light years away it’s so bright it’s easily visible using binoculars (if you happen to live in the southern hemisphere or not far from the equator). The reason it’s so bright is that this stellar nursery is churning out thousands of stars, and some of them are the massive, hot, and blue type. These flood the surrounding gas with ultraviolet light which makes the gas glow.

In fact, those young stars are so luminous and energetic they’re eating away the cloud from the inside out! Those big cavities you see are where the light and fierce winds of subatomic particles blown from the stars are slamming onto the gas, pushing it outwards. The edges of the cavities are bright because that’s where gas piles up, and shines more brightly.

In fact, the folks at Chandra released a similar version of this image, except they added observations from that observatory, which detects X-rays (as well as an image using Spitzer which sees in infrared). X-rays are emitted from extremely hot gas, and as you can see in the image inset here (click to embiggen) the cavities are filled with X-ray emitting material (colored blue in the image). I wrote more about this in a post when a similar image was released.

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CATEGORIZED UNDER: Astronomy, Pretty pictures

Desktop Project Part 2: Unicorn, rainbow… soot?

By Phil Plait | March 27, 2012 7:00 am

[Over the past few weeks, I’ve collected a metric ton of cool pictures to post, but somehow have never gotten around to actually posting them. Sometimes I was too busy, sometimes too lazy, sometimes they just fell by the wayside… but I decided my computer’s desktop was getting cluttered, and I’ll never clean it up without some sort of incentive. I’ve therefore made a pact with myself to post one of the pictures with an abbreviated description every day until they’re gone, thus cleaning up my desktop, showing you neat and/or beautiful pictures, and making me feel better about my work habits. Enjoy.]

Did you know there’s a unicorn in the sky? There is: the constellation Monoceros (literally, one-horn). Located near Orion, when we look in that direction we’re peering into the disk of our Milky Way galaxy, and that means seeing lots of gas and dust. And when you do that with a telescope like WISE that sees into the far-infared, what you get is, well, magic:

This is SH2-284, a star forming nebula. The image is false color, but each hue represents a different part of the infrared spectrum. Blue and teal is mostly coming from stars, while red and yellow is dust. Green comes from a very specific kind of material called a polycyclic aromatic hydrocarbons — long-chain carbon molecules which are essentially soot. PAHs are made in various ways, but are abundant where stars are being born, and that’s what we’re seeing here.

There’s a cluster of young stars in the center of this cloud, and they’re so hot they’re eating out the inside of the cloud, creating that cavity you can see. Like so many of these structures, the clock is ticking: many of those stars will explode, and when they do they’ll tear the cloud apart. So take a look while you can… this unicorn rainbow cloud only has a few million years left before it’s extinct.

Image Credit: NASA/JPL-Caltech/WISE Team

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Alphas in the heart of the Omega

By Phil Plait | January 5, 2012 7:00 am

After having recently posted an interesting picture of the results of star formation in a nearby galaxy, here’s another example, but far closer: an incredibly detailed image of the heart of the Omega Nebula, where stars are being born from huge clouds of gas and dust:

[Click to ennebulenate, or grab an even bigger version.]

This image was taken using the 8.2 meter Antu telescope, one of four making up the European Southern Observatory’s Very Large Telescope in Chile. What you’re seeing here is the central region of a much larger complex of gas and dust located about 6500 light years away toward the center of our galaxy. The whole thing is about 20 light years across, and perhaps as many as 1000 stars are in the process of being born or were recently formed there.

The red color is due to the presence of warm hydrogen gas, the basic building material of stars. It’s being lit up and is glowing due to very young, massive and hot stars — the alpha dogs, if you will — flooding the nebula with ultraviolet light. The dark material is actually dust, which is opaque in visible light, so it blocks the glow from material behind it.

That dust really caught my eye: some of it is not shapeless and random, but has been sculpted into very long, very thin wisps and tendrils. Most of these are parallel, which is a big clue to what causes them. They are most likely being shaped this way by shock waves; supersonic material blasted out from those same young, hot stars. These powerful stellar winds of subatomic material race out and slam into the surrounding material, compressing it. Waves from various stars can also collide, creating very thin streamers like this. Some are so narrow they’re barely resolved in the picture at all.

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Supernovae popping off like firecrackers in Carina

By Phil Plait | May 24, 2011 10:47 am

The Carina nebula is a sprawling, monstrous complex of gas located a mere 7500 light years from Earth. Hundreds of light years across, it’s massive enough to create thousands of stars like the Sun. Tens of thousands.

And churn out stars it does. Embedded in the nebula are several clusters of newborn stars, and many of these stars are so massive they’re nearly at the limit of how big a star can be without tearing itself apart. Stars that big explode as supernovae, and a new mosaic by the orbiting Chandra X-ray Observatory indicate they’ve been popping off in the nebula for quite some time:

[Click to enchandrasekharlimitenate.]

This image is pretty amazing: it’s a mosaic of 22 separate images by Chandra, covering 1.4 square degrees (seven times the area of the full Moon on the sky), and represents an exposure time of 1.2 million seconds! Since it shows X-rays coming from astronomical objects, it’s false color: red is from lower energy X-rays, green is medium energy, and blue from the highest energy photons.

The diffuse glow is from two sources: the stellar winds from those massive stars slamming into surrounding ambient gas at high speed, and from the shock waves generated when supernovae explode. Both are extremely high-energy events, and produce copious amounts of X-rays. That long, horizontal arc is probably the edge of a bubble, a shell of gas piled up from the winds of stars and supernovae like snow piled up in front of a snowplow.

That’s evidence right there that Carina has been cranking out supernovae over the past few million years. Interestingly, it’s what’s missing that provides more proof. Read More

The cold, thin, glorious line of star birth

By Phil Plait | April 14, 2011 7:00 am

At the end of May, 2010, the European Space Agency’s orbiting Herschel telescope was pointed toward a dark cloud in space over 2500 light years away. What it saw may solve a bit of a scientific mystery… and is also truly beautiful:

[Click to ennebulanate.]

This object is called IC5146, and consists of the Cocoon nebula on the left, and two long streamers of gas extending to the right. Herschel is very sensitive to cold dust in the very far infrared; in this image blue shows gas and dust emitting at a wavelength of 70 microns (the reddest color the human eye can see is roughly 0.7 microns), green is 250 microns, and red 500 microns — that’s over 700 times the longest wavelength light the eye can detect.

The Cocoon nebula is a well-known gas cloud being lit up by a massive, hot star in its center. In the visible light image inset here — grab the stunning high-res version to compare to the Herschel shot — the dust is dark, since it absorbs the kind of light we see. Also, stars are pretty faint at these extreme infrared wavelengths, so they don’t interfere with the observations of the gas and dust. That’s why observatories like Herschel are so important: they allow us to investigate objects that might be invisible to other telescopes.

As you can see in the Herschel image, the entire region is interlaced with long, thin filaments of dust. This dust is cold: much of it is only about 15° Celsius above absolute zero, or -430°F! What’s so very interesting is that the filaments, no matter what length they are (and as seen in other parts of the sky by Herschel as well), seem to have about the same width of roughly 0.3 light years across. That argues very strongly that these filaments are formed from turbulence in the dust, probably caused by exploding stars roiling up the matter between stars. That width is just about what you’d expect as shock waves from exploding stars slam into each other, interact, and become turbulent.

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An ionized rose would smell as sweet

By Phil Plait | March 30, 2011 10:20 am

I’m such a sucker for emission nebulae, the sites of intense star formation. Part of that is because I spent years researching other types of gaseous clouds, but also because they’re just so darn pretty, like this shot of NGC 371:

[Click to ennebulanate, or get the 2000 x 2000 pixel version).]

NGC 371 is in the Small Magellanic Cloud, a companion galaxy to our Milky Way. That puts it at a distance of about 200,000 light years, or 2 quintillion (2,000,000,000,000,000,000) kilometers.
Read More

CATEGORIZED UNDER: Astronomy, Pretty pictures

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