Astronomers on the Hubble team have released a spectacular image of the colorful planetary nebula NGC 2438.NGC 2438 is a planetary nebula located 1,370 light-years away in the southern constellation of Puppis.
Also known as HD 62099 and IRAS 07395-1437, the object was discovered by the German-born British astronomer William Herschel on March 19, 1786.
NGC 2438’s central star is a dim white dwarf with the surface temperature of about 75,000 K, making it one of the hottest stars known.
The nebula contains material ejected from the central star during the asymptotic giant branch stage, beginning some 8,500 years ago.
“The medium-sized star would have expelled its outer layers of gas into space as it died, leaving behind a white-dwarf core,” Hubble astronomers said.
“A halo of glowing gas over 4.5 light-years across surrounds the nebula’s brighter inner ring.”Many round or nearly round planetary nebulae display these halo structures, and astronomers have been investigating how they evolve.
NGC 2438 was one of the nebulae studied, and the researchers found that the nebula’s halo glows due to the ionizing radiation of the central white dwarf.
“In this color-filled Hubble image, blue represents oxygen (O III), green is hydrogen (H-alpha), orange is nitrogen (N II), and red is sulfur (S II),” they said.
“The image was captured by Hubble’s Wide Field and Planetary Camera 2 (WFPC2).”
“One of the camera’s four detectors provided a magnified view, which would be shrunk down in the final image to match the other three, creating the unique shape.”
