When stars like the Sun burn up all their fuel, they shed their outer layers, and the star’s core shrinks. Using NASA’s Chandra X-ray Observatory, astronomers have discovered a bubble of super-hot gas at the center of one of these effusive stars, the planetary nebula IC 4593.
The IC 4593 nebula is located in the Milky Way galaxy about 7,800 light-years from Earth. It is the most distant planetary nebula discovered by the Chandra telescope.
In this new image of IC 4593, the bubble detected by the Chandra telescope is gas heated to over a million degrees.
This composite image also contains visible light data from the Hubble Space Telescope. The pink areas in the Hubble image are an overlap of radiation from a colder gas composed of a combination of nitrogen, oxygen, and hydrogen, while green radiation is mainly associated with nitrogen.
Despite the fact that IC 4593 is called a planetary nebula, this class of objects has nothing to do with planets. The name of the cosmic phenomenon was given about two centuries ago because the nebulae looked like a disk of a planet when viewed through a small telescope. In fact, a planetary nebula forms after the interior of a star about the mass of the Sun shrinks, and its outer layers expand and cool. This happens during the “dying” of a star, at the end of its life cycle (which, however, can last for billions of years). As for the Sun, its outer layers could extend as far as Venus’s orbit during its red giant phase for several billion years in the future.
In addition to the hot gas, this study also finds evidence of a point X-ray source at the center of IC 4593. It has much more energy than a hot gas bubble. A point source could be either from a star that threw off its outer layers to form a planetary nebula or from a possible companion star in this system.