EVIDENCE FOR A BINARY ORIGIN OF THE YOUNG PLANETARY NEBULA HUBBLE 12

Young planetary nebulae play an important role in stellar evolution when intermediate- to low-mass stars (0.8–8 M) evolve from the proto–planetary nebula phase to the planetary nebula phase. Many young planetary nebulae display distinct bipolar structures as they evolve away from the proto– planetary nebula phase. One possible cause of their bipolarity could be a binary origin for their energy source. Here we report on our detailed investigation of the young planetary nebula Hubble 12, which is well known for its extended hourglass-like envelope. We present evidence with time-series photometric observations for the existence of an eclipsing binary at the center of Hubble 12. In addition, low-resolution spectra of the central source show absorption features such as CN, G band, and Mg b, which can be suggestive of a low-mass nature for the secondary component.