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Finding could help researchers learn more about inner workings and evolution of stars
By Mike Wall
Space.com
updated 8/26/2010 6:03:31 PM ET
Astronomers studying sound waves on a distant star have discovered that it has a magnetic cycle similar to our sun's solar cycle.
The find marks the first time astronomers have detected a star's magnetic cycle using a method called stellar seismology, which monitors the vibrations inside a star. The result could help researchers learn more about the inner workings and evolution of stars, including our own sun.
Originally posted by Pauligirl
So, how do acoustic fluctuations cause variations in light intensity?
Originally posted by rogerstigers
Maybe this is just semantics, but I can't see how they can detect "sound waves" on a distant star. From my understanding, sounds waves are actually a propegation of energy across a medium, not an actual medium of themselves. Given that, how can sounds waves propegate across the near vaccum of interstellar space?
Using the CoRoT (COnvection ROtation and planetary Transits) satellite, the astronomers measured the star's acoustic fluctuations, which CoRoT detected as slight variations in light intensity. By analyzing the vibrations, the researchers were able to map out some key details of HD49933's magnetic activity cycle.
they are recording the fluctuations in light intensity and using those measurements to create audible sound like the audio file below, except the file below is for a pulsar. all in all they are doing the same thing
nsfgov.http.internapcdn.net...
'Essentially, the star is ringing like a bell,' Metcalfe said in statement. 'As it moves through its starspot cycle, the tone and volume of the ringing changes in a very specific pattern, moving to higher tones with lower volume at the peak of its magnetic cycle.' OP Source
Originally posted by EnlightenUp
I thought the question was more along the lines of "how are the oscillations actually read off the star itself?" and relatedly, "what makes these oscillations visible?"
How do acoustic fluctuations cause variations in light intensity?
How can sounds waves propegate across the near vaccum of interstellar space?
Your attempted answer is, by the way, iwrong.
The star's mechanical vibrations show up as variations in its brightness. Here's how: the vibrations cause variations in the star's magnetic field. This in turn causes fountains of hot, bright gas to well up from its interior and subside in time to those magnetic variations. Thus, the brightness of the star increases and decreases in time to its mechanical vibrations.
What are these oscillations?
Leighton, Noyes, and Simon (1962) noticed in the spectrum of the Sun that some of the absorption lines were wiggling back and forth slightly with periods of around five minutes. Because the frequency of absorption lines can be shifted if the source is moving toward or away from the observer (the Doppler Shift effect), Leighton, Noyes, and Simon conjectured that the surface of the Sun is shaking back and forth. More careful observations revealed that while some parts of the surface of the Sun were moving towards us, other parts were moving away from us. It was as if there were waves, rising and falling on the surface of the Sun.
iwrong?
Originally posted by Astyanax
The star's mechanical vibrations show up as variations in its brightness. Here's how: the vibrations cause variations in the star's magnetic field. This in turn causes fountains of hot, bright gas to well up from its interior and subside in time to those magnetic variations. Thus, the brightness of the star increases and decreases in time to its mechanical vibrations.
Originally posted by Astyanax
Internet wrong. Virtually wrong, not absolutely wrong.
Either that, or itypo.