Slow rotation is also a hallmark of 4179 Toutatis, which is similar in size. However, it is not yet clear how such exaggerated rotation periods come about. For details and additional images, see the online press releases from Cornell University and JPL . The picture, taken in May 1999, is in the wavelength of glowing nitrogen gas. Click on image for larger view.
Astronomers call it a symbiotic star.
Such binary systems have nova-like brightenings as material from the red giant gradually spirals around the white dwarf. Once a critical mass is reached, an explosion blows the material outward. The outflows form a nebula within a nebula. The pictures were first presented earlier this month at a conference in Cambridge, Massachusetts. For details, see the online press release .