Spitzer peeks under a cradle’s blanket

By Phil Plait | February 12, 2008 9:52 am

I think one of the most amazing things we have learned in the centuries of the scientific pursuit of astronomy is that stars are born, they live out their lives, and that they die. That concept by itself is stunning: a process which takes billions of years can be understood, simply by knowing a few laws of physics and taking a look around.

And look we do. We have fantastic tools to investigate the lives of stars, and one of the best is the Spitzer Space Telescope. Don’t believe me? Then take a look at this stunner:

Spitzer took this gorgeous picture of the star forming region around the nearby star Rho Ophiuchi (just called Rho Oph for short). At 400 light years away, it’s one of the closest places where stars are actively being born, and so it provides us a front-row seat to the process.

However, the problem is that our great view to the show is blocked by a stage curtain. Star birth, like human birth, is messy. Gas and dust litter the nursery, obscuring what’s going on. Spitzer’s advantage is that it sees light in the infrared, which can penetrate the muck. The stars being born emit a lot of infrared light, so it can pierce the veil, so to speak, and reach us and our telescopes.

And what a sight! Infrared light emitted by the gas and dust themselves appears as tenuous wisps streaming across the view. The newborn stars shine brightly, and their fierce light (and strong solar winds) sculpt the gas, pushing it aside, carving sandbar-like shapes. Look at the windswept cloud just above the center of the image. That blob of material is probably a light year or more across, and its shape is due to the infant stars just below it and to the right in the picture. They are eroding it as surely as a river erodes away a spit of sand.

Spitzer can see different wavelengths, different colors of infrared as well, and this tells us different things about the nebula. For example, in the image above at the very left just below center is a red star, and you can just see that is has a fuzziness to it. In this case, the light we are seeing is coming mostly from very long infrared wavelengths (24 microns, for those keeping track at home; for comparison, a human hair is about 50 microns wide). But Spitzer can also see shorter wavelengths where the view is a little better, and it made an image of this nebula using those colors of infrared as well. Here is a side-by-side of the two images, zoomed in and centered on that fuzzy star:

On the left is the short wavelength image (in this case, 8 microns) and on the right is the 24 micron image (actually, they are composites of several wavelengths, but the longest wavelength in each is 8 and 24 microns, respectively). In the 8 micron image on the left, the nebulosity is easier to see, and reveals itself to be hourglass-shaped, pinched in the middle and flaring at the ends. Astronomers call this kind of nebula bipolar: the star is emitting gas from its poles in opposite directions. This is a dead giveaway that we’re looking at a very young star, only a few million years or so old. Rapid spin, strong magnetic fields and other forces are what focus that gas outflow, and the process itself will eventually slow the star’s spin like a parachute slows a skydiver. After a few dozen million years the flow will shut down, and the star will look a lot like the Sun.

So it’s not just looking in infrared that lets us peek into the cradle (to completely mix all metaphors), but it’s looking in different flavors of infrared that really lets us understand what’s going on. Because of telescopes like Hubble, Chandra, Spitzer, and ground based behemoths like Gemini, Keck, and the VLT — and a lot of smart people, hard work, and scientific progress — we now understand a fair bit about how stars are born. It’s an ongoing process of creation, it’s incredibly beautiful, and we understand it. How cool is that?


Comments (19)

  1. Here’s a hardcore astronomy question for you, Phil.

    We see, relatively often, stars exploding and ending their lives in a, umm, Earth-shattering kaboom as Marvin might say.

    Do we ever see a new star (or stars) where there wasn’t a star before? I can’t say I’ve ever seen a photo of such an event. One would think that just as stars explode into oblivion often enough for us to notice, so too must they ignite to begin their lives.

    It is likely that my understanding of stellar evolution is weak, but it would seem to me that as a star of solar mass coalesces out of the dust and gas that there must come a point when “bang!” fusion begins and luminosity shoots up relative to the ball-of-stuff-glowing-in-infrared-due-to-pressure-and-friction kind of luminosity that must exist before.

    So does this happen, or should I hit a university to look for a PhD sponsor and begin work? :)

  2. Cindy

    Evolving Squid,

    Fusion doesn’t begin with a bang. Instead, it’s a gradual process before you get a constant fusion rate. Also, the young star still has a lot of gas and dust around it when that happens. New stars arise from gas clouds, so it’s not like we have a clear view of the “before” – just a gas cloud.

    The endpoints of stars are easier to see because all the surrounding gas has been blown away long ago.

  3. Alex Besogonov

    Actually, fusion can’t start until proto-start cools enough – it’s heated by compression of the gas.

    So the first millions of years new stars don’t even need fusion to support themselves – they are hot enough.

  4. TheElkMechanic

    Living in New York, when a headline includes the word “Spitzer,” my default interpretation isn’t “a space telescope,” but rather “the governor.” So you can imagine the image your headline put in my head. Thanks for that.

  5. JJonahJansen

    As always, your enthusiasm for your subject and your ability to express it in a way that a non-astronomer like myself can understand is one of the many reasons I keep coming back to your site.
    I enjoy all your posts and the comments from your many erudite and well edumacated readers. Scrolling thru a few trolls here and there is a small price to pay to read your stuff and the comments from regulars like Quiet Desperation, Evolving Squid, Gary 7 (Am
    I the first to comment on the fact that Gary’s sig is the name of a one-off character from Star Trek for a spin off show that never happened? [LOVED that episode, even if it was a time travel story ;-)]) and Christian X Burnham and a host of others, right up to relative newcomers like Michael Lonergan. Go to other sites, compare the level of discourse on those and marvel at the intelligence, humour, and manners generally on display here. I thank you, and all those who support you, for helping to keep the light shining bright.

  6. uudale


    It’s now my new desktop background.


  7. Celtic_Evolution

    As they say in my native Boston… that is just wicked pissah! I never get tired of these amazing images and find that the science behind the images is even more fantastic. Makes the images themselves that much more enjoyable.

    I’m just completely geeked for the launch of the Herschel Space Telescope later this year!

  8. Arthur Maruyama

    Evolving Squid:

    As others have pointed out stars do not quickly ignite in the way a few spectacularly burn out as with novae and supernovae, but it is possible for stars and nebulae to be seen visually for the first time as was the case reported at this link:
    Sometime between 1991 and 2004 enough of the intervening obscuring clouds of gas and dust cleared away (perhaps by the star itself) so that we now have McNeil’s Nebula (there was a photo taken in 1966 which recorded a nebula there but it was not noted at the time).

    As always, BA: thanks for the pretty picture and explanation.

  9. madge

    I saw this on the nasa site and nearly fell off my chair in awe. Who needs magic, religion or the paranormal when stuff like this is going on all around us and we can see it and explain it?! Science rules!

  10. Is it just my imagination, or is it just an illusion?

    About 1/3rd from the bottom, above the word “Spitzer”, is a bright spot in the gas. Zooming the image to full size (rather than scaled to fit my screen, as the browser does by default) makes it look like a ring of gas and dust spiraling in towards the star in the middle of the bright spot.

    Is this what a proto solar system looks like at this stage, or is it my imagination getting ahead of things?

  11. Cory Albrecht

    Shouldn’t you be calling it ? Ophiuchi, with the Greek letter, just to be a real geek? :-)

  12. KaiYves

    Does anybody else see a hawk’s head in that image? Because I took one look at it and said “COOL, the Pheonix Force!”

  13. Andy C

    “Because of telescopes like Hubble, Chandra, Spitzer, and ground based behemoths like Gemini, Keck, and the VLT — and a lot of smart people, hard work, and scientific progress — we now understand a fair bit about how stars are born.”

    It’s all amazing stuff, and worth every penny that gets spent on such facilities. I just wish the British Government had noticed that before they walked away from Gemini at the beginning of this month.

  14. Crux Australis

    Of course, Corey, but the question mark isn’t a Greek letter! My browser (can’t speak for other people) doesn’t like ‘rho’ spelt correctly. Maybe I should change my encoding.

  15. Jeffersonian

    It IS Cool. Yup. Way.

  16. Nigel Depledge

    Thanks once again, BA, for a beautiful image and your articulate enthusiasm to go with it.

  17. madge writes:

    [[Who needs magic, religion or the paranormal when stuff like this is going on all around us and we can see it and explain it?!]]

    Well, for religion, I would say people need it who have a sense of their own sinfulness and want to become better people. I love science, but you can be a scientist, even a great scientist, and still be a failure as a human being — think Phillip J. Lennard or William Turner.

    I have loved astronomy all my life. I love it even more now that I can see the hand of God in creation.

  18. Do you have some “insider information” from NASA?


    This isn’t the first time one of your blog images ends up on APOD in a few days. (Or sometimes the next day.)

  19. Rai

    @ KaiYves. “Does anybody else see a hawk’s head in that image? Because I took one look at it and said “COOL, the Pheonix Force!”

    With the large gas cloud formation just above centre, being blown from bottom right by the newly formed stars, I would rather recommend it being called the lions head nebula (to me it fits the image of a large male lion looking down and to the right, with a flowing mane behind…that’s what happens when people born in africa look at nebulae…)

    Let’s see if anyone is still listening for a ‘ping’ on this blog…


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar