Hubble Captures a Protoplanetary Disk

Astroturtle writes "The Hubble Space Telescope's new Advanced Camera for Surveys (ACS) has captured a detailed image of spiral rings in a distant protoplanetary disk -- the pancake-shaped cloud of gas and dust around a young star in which planets are expected to condense. But contrary to earlier suggestions, the intricate structure of this particular disk is probably caused by a nearby companion star rather than by embedded planets starting to form."

Comments

Makes one wonder

[zokum]

Every time something like this is published, makes me wonder when we'll discover extra-terrestrial life. I honestly don't think it's a question of if, it's more about what, and whether they still are around. Seti@home might not be the solution, but as with all science, one has to start somewhere :-)

Re:Makes one wonder

[WegianWarrior]

It seems such a waste of space if we're alone... even more so if you're semi-religious as I am (I believe that science can explain most of the universe around us, but it was probaly the "great arcitect" that set it up to begin with). As we learn more about the universe and life, we may understand where and how to look for life out there.

Life is one thing, intelligence is different. Before we all get worked up over SETI@home, why not take a look at STI@home - the search for terrestial intelligence?

Re:Makes one wonder

[digital bath]

Hopefully. It would be a shame to have written all those sci-fi books and have them all turn out wrong...

Original Image

[StingRayGun]

It's nice to see the original image in this case. The color-enhanced added ones look pretty, and contribute to further exploration funding, but are often misleading.

Re:Original Image

[CheshireCatCO]

Why are they misleading? I'm a huge advocate of saying in captions when you've played with the colors (and how you've done so), but doing so is often perfectly good science. Stretching color tables let us see details that would otherwise be too faint for our eyes.

Proprietary Discs?

[yerricde]

After reading the headline, my first thought was of a copyright infringement sting operation. But then I realized it said "Protoplanetary" and not "Proprietary".

Jupiter and/or Saturn

[The Ape With No Name]

Help me with my astronomy! Can we infer that the Gas giants might have helped form the inner planets if a companion mass like a star or large planet is necessary to do so? I don't know the accepted timeline/sequence of planetary formation in our system, but this kinda popped to mind.

Re:Jupiter and/or Saturn

[CheshireCatCO]

Sorry, but not right. The proto-solar nebula was probably pretty well-mixed in elemental abundances. The reason you get rocky/metallic planets in close and icey giant planets further out is purely a matter of temperature. The inner disk is much hotter than the other disk, so that hydrogen compounds like methane, water and ammonia cannot condense into solid forms. Since there are 10 times as much of these compounds as metals and silicates, planets forming father out (past the "frost line" where water first can freeze out) have much more material to build with. Thus this build faster and into more massive bodies. At around 10 Earth-masses, the cores can start to hang on to nebular gasses like hydrogen and helium. And you get a giant planet. Inside the frost line, you're struck building with rocks and metals, and you get a smaller planet.

No pushing or pulling of specific elements/compounds is involved.

CENSORED!

[kinnell]

The black areas are omitted because of poor data

Yeah right! What they mean is that there was something phallic looking in the picture. Or maybe this is part of the movement to stop the publication of scientific findings which might be useful to terrorists. Either that, or they didn't want us to know about the alien civilisation they're waging a secret war against. Is nothing sacred?

Nics pics.

[Eevee]

I wouldn't say spectacular, but the photos are impressive for the detail available. (I'm spoiled from all the color nebula shots.) The spiral formations are easily visible, even without the 'cheatsheet' image.

Shame the images can't capture all the close-in dust. Considering that Pluto's only 40 a.u. out, having data from almost 100 a.u. around the star missing means a lot of the prime planetary formation area isn't available to examine.

OT gripe about idiotic web sites

[A nonymous Coward]

In this particular case, as in many many others, they insist on having cookies or they serve up a finger waving page, naughty naughty me, instead of the desired page.

What the heck is it with this infatuation with cookies? I have never been to Sky And Telescope before, there is nothing they need to remember about me, why do sites insist on even creating cookies before they are needed? Worset yet, why do they pretend they can't show any content without a cookie?

I know cookies have their uses, I have written many websites where the cookie holds a key to db records, and I can even understand the rationale news sites using cookies for ad tracking, annoying as it is, but even news sites generally don't refuse to show the page in question just because a cookie couldn't be set.

Yes, I will send a grip to the webmaster, but I also know it will be a waste of time.

Re:Spiral form

[Doctor Fishboy]

I thought that standard opinion on spiral forms (e.g. galaxies) was that they were created by interaction with massive companions.

Spirals in galaxies and these spirals in protoplanetary disks have different origins, and in the galactic spirals case, you don't need a binary companion to cause spiral structure.

Who has ever proposed that internal bodies can cause a spiral form?

OK, this is probably a gross simplification, so if there are any disk formation astronomers out there (you know who you are!), they'll give a much better description than this one!

It partially depends on the viscosity of the material in the disk, and where most of the mass resides. If the mass of the disk is much smaller than the mass of the central star, the disk structure is dominated by the gravitational field of the central star and this tends to smooth out any spiral structure in the disk, and then you need a binary companion to stir up spiral modes in the disk.

If the disk itself is massive enough, and the viscocity of the material is low enough, the disk's gravitational field can amplify up any spiral patterns that occasionally appear. So no, you don't need a binary compantion if the disk is massive enough. In this specific case, though, the disk mass is small, and so there's probably a binary companion acting as a swizzle stick.

For galaxies, nearly all the mass resides in the disk of the galaxy and not in the centre (the mass of the black hole in the centre of the galaxy is tiny compared to the rest of the mass in our galaxy, and there's a honking huge halo of dark matter, I know, I know...) and so spiral modes tend to be self-reinforcing as they sweep around the galaxy.

Blurgh, too early on Saturday morning...

Dr Fish

Re:It's all Greek...

[CheshireCatCO]

Translation:
"The star is a young fairly massive and hot star 320 light-years away (I'll let you look that one up if you don't already know it :-) in the constellation Libra (which is largely irrelevent, really.). It's brightness seen from Earth (presumably) is about a factor of two fainter than the faintest star you can see on a clear, dark night.

Here's a non-cookie site

[DrMorpheus]

Go to the source if you want to view the pictures without Sky and Telescope's insistence on putting a cookie on you system.

Here's the URL

Re:It's all Greek...

[reverseengineer]

Just adding to that excellent explanation, the arcane code HD 141569A merely gives the star's listing in the Henry Draper Catalogue, a gigantic star catalogue (over 250,000 entries) first compiled about a century ago. The spectral class A does denote that HD 141569A is a young, fairly massive, and hot star- its surface temperature should be between 7,500 - 10,000K, and it should be white to blue-white in color. Another example of an A type star would be Sirius.

I also wanted to point out that the story submitter gets it a bit wrong- which is more the fault of the story, which fails to make this clear- HD 141569A is not in a binary system with a single companion star, it is in a three star system with two other stars. These other two stars, HD 141569B and HD 141569C, are in a binary relationship with each other, and together perturb the disk around HD 141569A, which is over 100 billion miles from the pair. This paper (.pdf file) from 1999 on the Arxiv gives more details on the star system and protoplanetary disk.