Planet-Forming Disks Might Put the Brakes on Stars
Astronomers using NASA's Spitzer Space Telescope have found evidence that dusty disks of planet-forming material tug on and slow down the young, whirling stars they surround.
Comments:
This may be in the Astronomy 101 that I missed, but how is a star's rate of spin measured? Thank you.
I have read of 2 methods in use...<br><br>A: The Doppler method, measuring the "widening" of the spectral lines caused by the fact that one side of the star is moving toward us and the other moving away.<br><br>B: The sunspot method - measuring the rhythmic dips in brightness caused by traversing sunspots.<br><br>-PSW
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