AstronomyPicture of the Day—20181125

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2018 November 25

TheLonely Neutron Star in Supernova Remnant E0102-72.3

Credit:X-ray (NASA/CXC/ESO/F. Vogt et al.); Optical (ESO/VLT/MUSE & NASA/STScI)

Explanation:Why is this neutron star off-center? Recently a lone neutron star has beenfound within the debris left over from an old supernova explosion. The"lonely neutron star" in question is the blue dot at the center ofthe red nebula near the bottom left of E0102-72.3. In the featured imagecomposite, blue represents X-ray light captured by NASA's Chandra Observatory,while red and green represent optical light captured by ESO's Very LargeTelescope in Chile and NASA's Hubble Space Telescope in orbit. The displacedposition of this neutron star is unexpected since the dense star is thought tobe the core of the star that exploded in the supernova and created the outer nebula.It could be that the neutron star in E0102 was pushed away from the nebula'scenter by the supernova itself, but then it seems odd that the smaller red ringremains centered on the neutron star. Alternatively, the outer nebula couldhave been expelled during a different scenario -- perhaps even involvinganother star. Future observations of the nebulas and neutron star appear likelyto resolve the situation.