1 / 7

Helioseismology: The Vibrations of the Sun Revealed

Delve into the fascinating field of helioseismology, exploring the Sun's oscillations and the spectrum estimation methods used. Discover the history of stellar oscillations, observe the Sun's vibrational patterns, and unravel the intricacies of spherical waves. Learn how acoustic waves are trapped within the Sun, leading to a meticulous spectrum analysis that unveils over 250,000 distinct modes. Explore the regularity of the Sun's spectrum, the prediction of energy propagation, and the nuances of 5-minute oscillations excited by convection. Engage with advanced concepts and data analysis techniques to decode the vibrational secrets of our star.

hartmanl
Download Presentation

Helioseismology: The Vibrations of the Sun Revealed

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Spectrum Estimation in Helioseismology P.B. Stark Department of Statistics University of California Berkeley CA www.stat.berkeley.edu/~stark

  2. Acknowledgements • Most figures pirated from Global Oscillations Network Group (GONG) and Solar and Heliospheric Observer (SOHO) Solar Oscillations Investigation websites • Much work joint withI.K. Fodor (LLNL), D.O. Gough (Cambridge), Y. Gu (GONG), R. Komm (GONG), C.R. Genovese (Carnegie-Mellon), T. Sekii (Cambridge), M.J. Thompson (Queen Mary and Westfield College).

  3. The Sun Vibrates

  4. The Sun Vibrates • Stellar oscillations known since late 1700s. • Sun's oscillation observed in 1960 by Leighton, Noyes, Simon. • Explanation as trapped acoustic waves by Ulrich, Leibacher, Stein, 1970-1.

  5. Pattern is Superposition of Modes • Like vibrations of spherical guitar string • 3 “quantum numbers” l, m, n • l and m are spherical surface wavenumbers • n is radial wavenumber

  6. Spectrum is very Regular • Explanation as modes predicts details of spectrum • Details confirmed in data by Deubner, 1975 • Over 107 modes predicted • Over 250,000 identified • Will be over 106 soon

  7. “5-minute” oscillations • Takes a few hours for energy to travel through the Sun. • p-mode amplitude ~1cm/s • Brightness variation ~10-7 • Last from hours to months • Excited by convection 40-day time series of mode coefficients, speeded-up by a 42,000. l=1, n=20; l=0, 1, 2, 3 Source: Kosovichev, SOHO

More Related