A dying star. Chi Cygni, shown in this artist's conception, is a red giant star nearing the end of its life. As it runs out of fuel, it pulses in and out, beating like a giant heart and ejecting shells of material. Observations by the Infrared Optical Telescope Array found that, at minimum radius, Chi Cygni shows marked inhomogeneities due to roiling "hotspots" on its surface. (Credit: ESO/L. Calçada)
Planetary Nebula NGC 2818 | The Hubble Space Telescope has imaged striking details of the famed planetary nebula designated NGC 2818, which lies in the southern constellation of Pyxis (the Compass). The spectacular structure of the planetary nebula contains the outer layers of a star that were expelled into interstellar space.
This planetary nebula, Mz3, is being cast off by a star similar to our Sun. The 1000-kilometer per second speed of the expelled gas, the light-year long length of the structure, and the magnetism of the star visible at the nebula's center, all imply Mz3 is hiding a second, dimmer star that orbits close in to the bright star. A competing hypothesis holds that the central star's own spin and magnetic field are channeling the gas. (ESA, NASA's Hubble, JPL-CalTech)