Interstellar gas clouds聽vibrate聽like ringing bells. Those vibrations and the patterns they leave behind may help us understand the factors that control how many stars of different types are born deep within these stellar nurseries.
The universe is chock full of enormous clouds of gas, but it鈥檚 difficult for us to determine their 3D shapes. They are extremely far away so we only see an outline on the sky, which can be deceiving. For example, a cylinder-shaped cloud could look the same as a disc or a sphere, if its circular end is the only part visible from the angle we鈥檙e viewing it.
and at the University of Crete in Greece, found a new way to measure the 3-D shape of a gas cloud called Musca about 500 light years away, using magnetic vibrations that ripple through it.
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Musca, like many other gas clouds in space, has dense areas arranged in parallel filaments. Previous work has that shown that magnetized pressure waves that pervade the cloud likely compress the gas into these thin, stringy filaments, which are oriented parallel to the magnetic field lines.
The frequencies of the waves are dependent on the cloud鈥檚 shape and size. 鈥淟ike a violin and a cello make different sounds, clouds with different shapes and sizes will also produce different tunes 鈥� we will see different frequencies,鈥� says Tritsis.
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A slice of the galaxy
The researchers used simulations to figure out what the cloud鈥檚 shape would have to be to create these resonating vibrations. Astronomers previously thought Musca was a long, skinny cylinder, but this analysis showed that it鈥檚 actually flatter and wider, shaped like a thick slice of bread. We knew that it was about 27 light years long and less than half that distance in thickness, and now we know that it鈥檚 20 light years wide.
The dense filaments in clouds like Musca are where much of the galaxy鈥檚 star formation occurs, so having detailed models of their structure can help us understand how stars are born.
鈥淭he underlying physics that shapes the clouds also determines how many stars will form and what will be the mass distribution of these stars,鈥� says Tritsis.
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