Asteroseismology with the AFOE


Asteroseismology is the study of stellar oscillations in stars like our Sun (i.e., the study of starquakes). From the study of these starquakes we can infer some of the properties of these stars, in a way similar to what has been learned about the Earth interior from the way earthquakes propagate.

Oscillations in a star cause motions of material in the stellar atmosphere. The radiation emitted by this moving material is shifted in wavelength by the Doppler effect -- material that is approaching the telescope emits light that is shifted to bluer wavelengths, while material that is receding is red-shifted. Since the AFOE is expressly designed to measure these wavelength shifts with great precision, it is possible to use it to detect the very small motions associated with Sun-like stellar pulsations.

The AFOE is capable of detecting velocities as small as 1 meter per second (or 2.2 mph), on a relatively bright star.


The AFOE has monitored several stars to attempt to detect these small oscillations.


  1. A Radial Velocity Search for p-Mode Pulsations in eta Boötis, Brown et al., 1997, Ap.J.,475, 322.
  2. Use of Temperature-Sensitive Line Ratios for Stellar Seismology, Noyes, R W., Korzennik, S.G., Krockenberger, M., Nisenson, P., Brown, T.M., Kennelly, T., Horner, S., 1996, BAAS, 188, 5906.
  3. A Radial Velocity Search for p-modes in Procyon, Brown, T.M. Kennelly, E.J., Noyes, R.W., Korzennik, S.G., Nisenson, P., Horner, S.D., Catala, C., 1996, BAAS, 188, 5902.
  4. The Oscillation Modes of epsilon Cep and tau Peg, Horner, S.D., Kennelly, E.J., Brown, T.M., Noyes, R.W., Korzennik, S.G., Nisenson, P., YANG, S., Walker, A., 1996, BAAS, 188, 5901.
  5. Solarlike oscillations in eta Boötis, Kjeldsen et al., 1995, A.J, 109, 1313.
  6. Asteroseismology, Brown, T.M. & Gilliland, R.L., 1994, Ann Rev. Astron. Astrophys. vol. 32, pp. 37-82.
  7. Detection of possible p-mode oscillations on Procyon, Brown et al., 1991, Ap.J.,368, 599.
Sylvain G. Korzennik (
Timothy M. Brown (
Last modified: Thu May 1 12:47:02 1997