The space around a newly forming star is a busy construction zone. A giant disk of gas and dust encircles the protostar — the blob of hot material that will someday form the star. Some of the material in the disk feeds into the protostar, while some squirts out into space in high-speed “jets.” The jets can be clumpy, and if one clump overtakes another, it forms a glowing cloud.
Two such clouds are in Sagittarius, which is low in the southern sky at nightfall, with its brightest stars forming the outline of a teapot.
The clouds are Herbig-Haro 80 and 81. They’re associated with a protostar that’s about 15 times as heavy as the Sun. The disk of gas and dust around it is many times wider than our own solar system. A powerful magnetic field snags charged particles and fires them into space above the protostar’s north and south poles. These jets of material span close to 20 light-years.
The jets aren’t smooth, like the spray from a water fountain. Instead, they’re clumpy. The clumps can be several times heavier than Earth, and they shoot into space at hundreds of thousands of miles per hour. The clumps move at different speeds, though. Herbig-Haro 80 and 81 are regions where a faster clump has overtaken a slower one. That creates a shock wave that heats the gas, setting it aglow — creating a beautiful and rapidly changing cloud next door to a future star.
We’ll talk about some even stronger jets tomorrow.
Script by Damond Benningfield, Copyright 2014
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