Planetary Nebula Abell 78 captured by the Hubble Space Telescopes’ Wide Field Camera 3 and PANSTARSS. Credit: ESA / Hubble & NASA, M. Guerrero, Acknowledgments: Judy Schmidt
Located about 5,000 light-years away in the constellation Cygnus (the Swan), Abell 78 is an unusual type of planetary nebula.
After the nuclear fuel in their cores is exhausted, stars about 0.8 to 8 times the mass of our Sun collapse to form a dense and hot white dwarf stars. While this process takes place, the dying star will shed its outer layers of material and form an extensive gas and dust cloud known as a planetary nebula. This phenomenon is not uncommon, and planetary nebulae are a popular focal point for astrophotographers because of their often beautiful and complex shapes. However, a few like Abell 78 are the result of a so-called “born again” star.
Although the star’s core has stopped burning hydrogen and helium, a surface thermonuclear runaway ejects material at high speeds. This ejecta shocks and sweeps up the material from the old nebula, creating the filaments and irregular scale around the central star seen in this Photo of the Week, which includes data from Hubble’s Wide Field Camera 3 and PANSTARSS.