Dust Cloud Blooms Like a Flower in the Sky (Photo)

The entire universe in blog form
Jan. 6 2013 8:00 AM

A WISE Flower Blooms in the Sky

One of my favorite space missions is WISE: the Wide-field Infrared Survey Explorer, which mapped the entire sky in the far-infrared, well outside what our mere human eyes can see. At those wavelengths, objects we'd consider to be frigidly cold glow brightly. Those include clouds of dust and gas surrounding freshly-born stars, like the nebula called LBN 114.55 + 00.22:

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

You can see why I like WISE so much; the images it sent to Earth were spectacular! [Click to embiggen.] LBN 114 (for short) is a classic star-forming region. About 30 light years in diameter, it’s a dense clot of gas and dust, and in its core it’s busily churning out new stars. Some of these are massive, hot, blue stars, which blast ultraviolet light and also blow out a gale of subatomic particles, like the solar wind but far faster and stronger. The light and winds from these stars eats away at the inside of the cloud, carving a cavity in it.


You can actually see that in this image; the center of the nebula is dimmer, where the gas and dust have been pushed away. The overall effect makes LBN 114 look like a vast flower in space—though one that’s 300 trillion kilometers across.

You may have noticed the central part of the nebula is red. Why would that be if the stars lighting it up are blue? There’s more than one reason, but first, remember this is an infrared picture. What you see as red is actually way out in the infrared, at a wavelength of 22 microns (compare that to the reddest light the eye can see, at about 0.7 microns). Green is 12 microns, cyan is 4.6, and blue is 3.6 microns. As a rule of thumb, the cooler an object is, the redder the light it emits. So in WISE images the warmest objects are blue, and the coolest red.

A Celestial Shamrock
WISE image of the star CY Cam, with metallic dust glowing red. Click to enhoovernate.

Image Credit: NASA/JPL-Caltech/WISE Team

Star birth regions like LBN 114 are choked with complex organic molecules called polycyclic aromatic hydrocarbons, or PAHs. Think of it as soot, which is pretty close to what it is! Warm interstellar dust tends to glow very strongly at around 12 microns, which is why you see so much frilly green material in images like this. Cooler dust emits at 22 microns, so it looks red in WISE images. You might expect that near the hot stars the dust would be even warmer, but things can get complicated.  For example, some dust is laden with metals like magnesium and silicon, which help the dust cool off. This is pretty commonly seen in WISE images of objects like this (such as the Lambda Centauri Nebula, and the dust surrounding the star CY Camelopardalis—click those for more beautiful WISE images).

As an aside, the bright star in the picture is called HIP 117078, a massive red supergiant near the end of its life. It’s a long way off, 18,000 light years or so, three times farther than LBN 114. One day it’ll explode, but probably not for a long time…and it’s too far away to hurt us here on Earth.

As you can see, this whole region of space is thick with dust, which absorbs visible light pretty well. There’s a lot of gas in this nebula, which glows strongly in visible light. However, in visible light this nebula is pretty faint when seen from Earth because all that dust in the way sucks down the light. At its distance of 6000 light years, LBN 114 is about half the size of the full Moon on the sky, yet it’s a relatively obscure object (I couldn’t find much in the professional journals about it). If there were no dust in the way, it might be visible to the naked eye on a dark night.

And this is why we build observatories like WISE: to show us what we otherwise could not see. How can we possibly understand what’s going in the Universe around us if we’re missing pieces of the puzzle? I wish we had a dozen observatories like WISE peering into the dark…because at some wavelengths, the Universe isn’t so dark. And we might not otherwise know.


War Stories

The Right Target

Why Obama’s airstrikes against ISIS may be more effective than people expect.

Why Is This Mother in Prison for Helping Her Daughter Get an Abortion?

The XX Factor
Sept. 23 2014 11:13 AM Why Is This Mother in Prison for Helping Her Daughter Get an Abortion?

Divestment Is Fine but Mostly Symbolic. There’s a Better Way for Universities to Fight Climate Change.

I Stand With Emma Watson on Women’s Rights

Even though I know I’m going to get flak for it.

It Is Very Stupid to Compare Hope Solo to Ray Rice

Building a Better Workplace

In Defense of HR

Startups and small businesses shouldn’t skip over a human resources department.

It’s Legal for Obama to Bomb Syria Because He Says It Is

How Ted Cruz and Scott Brown Misunderstand What It Means to Be an American Citizen

  News & Politics
War Stories
Sept. 23 2014 4:04 PM The Right Target Why Obama’s airstrikes against ISIS may be more effective than people expect.
Sept. 23 2014 2:08 PM Home Depot’s Former Lead Security Engineer Had a Legacy of Sabotage
Sept. 23 2014 1:57 PM Would a Second Sarkozy Presidency End Marriage Equality in France?
  Double X
The XX Factor
Sept. 23 2014 2:32 PM Politico Asks: Why Is Gabby Giffords So “Ruthless” on Gun Control?
  Slate Plus
Political Gabfest
Sept. 23 2014 3:04 PM Chicago Gabfest How to get your tickets before anyone else.
Brow Beat
Sept. 23 2014 4:45 PM Why Is Autumn the Only Season With Two Names?
Future Tense
Sept. 23 2014 1:50 PM Oh, the Futility! Frogs Try to Catch Worms off of an iPhone Video.
  Health & Science
Sept. 23 2014 4:33 PM Who Deserves Those 4 Inches of Airplane Seat Space? An investigation into the economics of reclining.
Sports Nut
Sept. 18 2014 11:42 AM Grandmaster Clash One of the most amazing feats in chess history just happened, and no one noticed.