Helio- and Asteroseismology
INTRODUCTION
| OBSERVATIONS : the SUN
| OBSERVATIONS : STARS
| MODELS
| SOLAR OSCILLATIONS
| RESULTS
WHO ARE WE ?
Nodal points
An oscillation on the surface of the Sun or a distant star has a
characteristic pattern of nodal points, where there isn't any motion,
distributed over the solar or stellar disc
You can think, for example, of a skipping rope, which is fixed at
one end, while the other end is moved up and down vigorously.
If you move your hand with an appropriate speed, you can
create a so-called standing wave, where the nodal points
are the places on the rope that are standing still, while the rest
of the rope moves up and down.
On a two-dimensional surface, such as a drumskin or the solar surface,
the nodal points are arranged in nodal lines;
in a three-dimensional object, for instance the solar interior,
the nodal points form nodal surfaces.