Category Archives: starbirth

astronomy, astronomy news, star death, starbirth

Whoa, Horsie!

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Humans have the most amazing propensity to use animal “avatars” to illustrate things. A couple of entries back I wrote about cats in the sky. There are also sea creatures and even birds and bees up there! But the animalization of space isn’t limited to constellations. This deep-sky object is called the Horsehead Nebula — for the obvious reason. It’s actually a cloud of gas and dust that happens to lie in front of a bright, glowing cloud of gas and dust. The superposition of one over the other gives us the lovely vision of a horse’s head.

The Horsehead Nebula, courtesy European Southern Observatory
The Crab Nebula, courtesy of European Southern Observator

This high-resolution image from the European Southern Observatory takes what looks like a serene scene and shows us how very chaotic the situation is at this nebula. You can see wisps and filaments in the gases, and clouds of diffuse dust. If you look at the top of the figure you see a bright rim separating the dust from the gas cloud (also known as an H II region). Astronomers call this region an “ionization front” where the photons from the HII region are moving into the cloud. Their energy is emitted as heat, which is destroying the dust and the molecules and lighting up the gas.

Actually, the Horsehead is a short-lived object. The continual erosion of the gas and dust by the emissions from nearby stars will eventually destroy the clouds in a few thousand years. So, enjoy this deep-sky animal while we have it!

The Crab Nebula, courtesy of European Southern Observatory
The Crab Nebula, courtesy of European Southern Observatory

Also lurking within the confines of the constellation Taurus, the Bull, is the Crab Nebula, so named because through smaller telescopes it appears as a crab-like ghostly apparition. In reality, this thing is an expanding cloud of gas and dust marking the spot of a cataclysmic explosion called a supernova. It first shone in our skies in the year 1054 A.D. and was observed by the Chinese, Japanese, and very likely the Anasazi tribes of the American Southwest.

The Crab contains a neutron star near its center that spins 30 times per second around its axis, the remains of the original star. It flashes light pulses 30 times a second (making it a pulsar). In this picture, green light is predominantly produced by hydrogen emission from material ejected by the star that exploded. The blue light is emitted by very high-energy electrons that spiral through a huge magnetic field twisted around the pulsar.

Of course we don’t see any of this through our backyard-type telescopes — for most of us this just looks like a dim little glow in the sky, hidden more than 6,000 light-years away and unlikely to do us any harm.

galaxies, galaxy interactions, galaxy shapes, starbirth

Visions from the Cosmos

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I’m working on a book and a planetarium show script these days — good things to be doing in the dog days of August! The book is a sort of general survey of astronomy and the script is about Hubble Space Telescope science. And of course, there are hundreds of great images from HST to show off. If you’re into exploring the universe with HST, visit Hubblesite and lose yourself in the cosmos for a while! And then when my book comes out sometime in 2003, you can read all about the science behind the great images from HST, Chandra, and all their sister observatories. In the meantime, here are a couple of interesting images from HST.

Hamburgers Anyone?

Gomezs Hamburger Object
Gomez's Hamburger Object

Probably just in time for summer cookout season, HST Heritage project astronomers took a close-up look at an object nicknamed Gomez’s Hamburger. This familiar-looking object was named after its discoverer — Arturo Gomez (who does his observing at the Cerro Tololo Inter-American Observatory in Chile). It may look strange, but this is a Sun-like star in its early death throes. You can’t exactly see the star because it’s hidden behind a ring of gas and dust. But you can see the light from the star emerging in a perpendicular direction to the disk. In a thousand years or so, the dying star will get hotter than its current 18,000 degrees — hot enough to evaporate away all that gas and dust. It should be a beautiful sight for our future generations!

Warp Me A Galaxy, Scotty!

ESO 510-G13 (Its a galaxy!)
ESO 510-G13 (It's a galaxy!)

There are many strange-looking things out in the universe — at least they’re strange until you understand what you’re seeing. In this case, what we’ve got here is ESO 510-G13 — an edge-on galaxy that has been twisted and warped by a collision with another galaxy. The titanic gravitational forces have, over millions of years, deformed the galaxies. Not only is the dark dust lane tracing the deformity, but the bright blue clouds of light on the right-hand side of the image are the first generation of massive newborn stars to be formed as a result of this galactic merger. Eventually the shock waves from the head-on collision will die out and a single, normal-looking galaxy will exist here.