Hubble spies on unusual planetary nebula

Planetary Nebula Abell 78 captured by the Hubble Space Telescope 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 depleting the nuclear fuel in their hearts, stars with a mass of about 0.8 to 8 times the mass of our Sun collapse to form dense, hot stars. white dwarf stars. As this process occurs, the dying star will reject its outer layers of material, forming an elaborate cloud of gas and dust known as the planetary nebula. This phenomenon is not uncommon and planetary nebulae are a popular focus for astrophotographers due to their often beautiful and intricate 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, thermonuclear runaway on its surface ejects matter at high speed. This ejecta shocks and sweeps away material from the ancient nebula, producing the filaments and irregular shell around the central star seen in this Image of the Week, which features data from Hubble’s Widefield Camera 3 and PANSTARSS.