1 / 19

Acoustic Oscillations in Red Giants

Acoustic Oscillations in Red Giants. Jim Fuller Caltech/KITP. Quiz: In which decade was the first Pulsating Red Giant Discovered?. Answer: 1596 Mira’s variability discovered by David Fabricious. Luminosity variations from Acoustic Oscillations. Chaplin & Miglio 2013.

tiger-henson
Download Presentation

Acoustic Oscillations in Red Giants

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. Acoustic Oscillations in Red Giants Jim Fuller Caltech/KITP

  2. Quiz: In which decade was the first Pulsating Red Giant Discovered? Answer: 1596 Mira’s variability discovered by David Fabricious

  3. Luminosity variations from Acoustic Oscillations

  4. Chaplin & Miglio 2013

  5. What are Acoustic Oscillations? • Sound waves in star • Waves are excited by convective motions • Sound waves reflect, create global-scale standing waves, i.e., oscillation modes, at characteristic frequencies

  6. Characteristic frequencies • Stellar dynamical frequency • Freefall frequency, orbital frequency at stellar surface

  7. Characteristic frequencies • Acoustic cutoff frequency • Characteristic atmospheric frequency

  8. Oscillation frequencies • Stars tend to oscillate at frequencies • Oscillation spectrum exhibits peaks separated by

  9. Spherical harmonics m l

  10. Chaplin & Miglio 2013

  11. Evolution up Giant branch • As stars evolve up RGB or AGB, their radii increase dramatically • Mode frequencies and frequency spacing decrease • Longer observation baselines needed • Continuous data not needed • Mode amplitudes increase • Less sensitivity needed to detect oscillations

  12. Mosser et al. 2013

  13. Mosser et al. 2013

  14. Scaling relations Chaplin & Miglio 2013

  15. Lower red giant branch Chaplin & Miglio 2013

  16. Rotational splitting Mosser et al. 2012

  17. upper red giant branch Mosser et al. 2013

  18. Power of PTF • PTF has ability to detect oscillations in lots (millions?) of red giants • With measurement of mode frequencies and spacings, PTF can characterize these stars • Provides synergy with K2, GAIA, TESS, PLATO, LSST, etc.

More Related