FIGURE 2.8 Hubble Space Telescope image of the planetary nebula NGC 6543, commonly known as the Cat’s Eye Nebula. The inset shows the lower-magnification ground-based image made using the 2.1-m telescope at Kitt Peak National Observatory under excellent atmospheric conditions. Stars with a mass less than about eight times that of the Sun evolve to red giant stars, and the red giants end their lives by ejecting their outer envelopes. The ejected envelopes glow in visible light and are called planetary nebulae. This image shows the ejected gas, enriched in elements such as carbon by the nucleosynthesis that occurred in the parent star, as it travels outward into the interstellar medium to be incorporated eventually into new stars and planets. The Hubble image was obtained by J.P. Harrington and K.J. Borkowski (University of Maryland), and NASA, and was recolored by B. Balick (University of Washington) with permission. The ground-based image is courtesy of B. Balick.