Baby Pictures…

It seems somehow humbling… This is an image of a baby star. Isn’t it cute? It’s name is L1157 and it’s only a few thousand years old, which in star terms is practically newborn. Young stellar objects like this one are known as T Tauri Stars and images of them are extremely rare. Being hidden deep inside a dark nebula, this image was taken with NASA’s Spitzer telescope, and is only visible in infrared. It’s morphology is not unlike the artists impression I made a while ago.

That blue/black smudge in the centre is it’s circumstellar disk. In the very centre, impossible to see but for the glare of the star, this disk is heated to temperatures high enough to knock away electrons and turn it into plasma. The circumstellar matter is then caught in the star’s magnetic field and siphoned down to the star’s surface in vast plasma columns, large enough to melt the Earth. Being pulled through the young star’s corona, this plasma is likely to reach millions of degrees, due to heating by Alfvén waves. These magnetic waves are the reason why our Sun’s corona is so hot, and it’s highly likely that a similar process would happen in the highly convective atmospheres of young stars such as this one.
The huge flame-like objects are from the star’s circumstellar jets. These show that it’s still growing, feeding off the darker material surrounding it. As it does so, these huge jets spew out into space to conserve angular momentum. If they didn’t the star would spin itself apart long before it ignited fusion. In fact, those jets are so long, it takes light about nine months to travel the distance from the star to either end.

In a couple of million years, the disk and jets will gradually disperse, likely leaving planets (or planetessimals) in their wake. L1157 will probably be very similar to the Sun in mass and brightness when it’s fully grown. Humbling, as it’s almost like looking back in time… Our own sun once would have had jets of it’s own.


About Invader Xan

Molecular astrophysicist, usually found writing frenziedly, staring at the sky, or drinking mojitos.
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