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Planetary Nebula Hydrodynamics:

Movies of Numerical Work

See the printed papers on my PN site, or browse in the electronic issues of Astronomy &Astrophysics. Caution Websurfers: these movies take quite a while to download! They are given in two formats: one low-quality at high compression, and one high quality that has about twice the size of the compressed version. For people with slower line connections, I have included a few movies of low-resolution simulations. All movies are in QuickTime format (Movie JPEG A-compression).

 

Case 1: Conical Inflow

In these computations, the inflow from the central star is initially in the form of a hollow cone, due to the (unseen) focusing of the inner shock around the white dwarf. The shape of the outer nebula is not very strongly influenced by this choice, as we will see below in the simulations that start from a spherical inflow.

Bipolar Nebula Shaped by a Conical Supersonic Inflow

Click to enlarge
 Numerical computation of a conical gas stream shooting into a slightly flattened atmosphere. In this composite image, red indicates the density, green the temperature, and blue the velocity of the gas. The image is cylindrically symmetric about the horizontal axis. The dying star, which is now a young white dwarf, is in the centre of the image. The image of Mz3 roughly corresponds to the red part. You can download a low-quality movie (2.9 Mb) or a high quality movie (4.4 Mb). Both movies are in QuickTime format.

The image of Mz3 as seen in the sky is not the same as what you see in this simulation. The reason is, that the nebula is illuminated by the strong light source in the centre. This probably causes the "legs" and other wisps surrounding the "ant's body". Part of the emission of the nebula is obscured somewhat by an equatorial belt crossing the star, seen edge-on. This is all that remains of the "solar system" that probably orbited around the central star of Mz3. Note the prominent bubble caps sticking out of the main lobes of this bipolar nebula. My simulations show that this remarkable feature is due to an inward deflection of the highly supersonic gas that bounces off the inner walls of the nebula, causing a double vortex that moves outward with great violence. You can see this happen as you play the movie.

Conical Supersonic Inflow: density, temperature, velocity

Numerical computation of a conical gas stream shooting into a slightly flattened atmosphere. In this movie, the leftmost panel indicates the density, the middle panel shows the temperature, and the rightmost one the velocity of the gas. The dying star is in the bottom-left corner of each image. The colour red indicates high values, blue is low. The image is cylindrically symmetric about the vertical axis, and reflection-symmetric about the bottom line. You can download a low-quality movie (1.9 Mb) or a high quality movie (4.5 Mb). Both movies are in QuickTime format.

Notice also the parabolic caps sticking out at the ends, and the rings around the waistline and around the main bubbles. These are due to turbulent ripples propagating up into the cavities blown by the wind from the central star. This effect is clearly visible in these movies where you see the flow in cross section.

Conical Supersonic Inflow: density

Click to enlarge
 Numerical computation of a conical gas stream shooting into a slightly flattened atmosphere. In this movie you see only the density of the gas. Red indicates high values, blue is low. The image is cylindrically symmetric about the horizontal axis. You can download a low-quality movie (3.7 Mb) or a high quality movie (5.2 Mb). Both movies are in QuickTime format.

Conical Supersonic Inflow: temperature

Click to enlarge
 Numerical computation of a conical gas stream shooting into a slightly flattened atmosphere. In this movie you see only the temperature of the gas. Red indicates high values, blue is low. The image is cylindrically symmetric about the horizontal axis. You can download a low-quality movie (4.4 Mb) or a high quality movie (6.5 Mb). Both movies are in QuickTime format. This type of temperature distribution ought to be observable in X-rays.

Conical Supersonic Inflow: velocity

Click to enlarge
 Numerical computation of a conical gas stream shooting into a slightly flattened atmosphere. In this movie you see only the velocity of the gas. Red indicates high values, blue/purple is low. Notice that the velocity drops abruptly beyond the red region: this is a shock wave. The image is cylindrically symmetric about the horizontal axis. You can download a low-quality movie (3.8 Mb) or a high quality movie (5.3 Mb). Both movies are in QuickTime format.

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