The Planetary Nebula K 648 in the Globular Cluster M15

Our team has obtained HST WFPC2 images of this prototypical example of a planetary nebula in a globular cluster. K 648 was cataloged as a star by Kustner, but identified spectroscopically as a planetary nebula by Pease, both in the 1920's.

General WFPC2 view of M15 and K 648 (located near top left edge)

Closeup false-color image of the planetary nebula (red = [N II], green = H-alpha, blue = [O III])
Click for paper (Alves, Bond, & Livio; Astronomical Journal 120, 2044, 2000). The paper deals with the (non)-variability of the central star, morphology of the nebula, and evolution of the nucleus. The nucleus is shown to have an unusually high mass of 0.60 Msun, and we argue that it must have undergone mass augmentation in a binary that has undergone mass transfer or a merger.

Last updated 2000 October 19