Abundance Analysis of the J4 Equatorial Knot of the Born-again Planetary Nebula A30

Abstract

A30 belongs to a class of planetary nebulae identified as "born-again", containing dense, hydrogen-poor ejecta with extreme abundance discrepancy factors (ADFs), likely associated with a central binary system. We present intermediate-dispersion spectroscopy of one such feature-the J4 equatorial knot. We confirm the apparent physical and chemical segregation of the polar and equatorial knots observed in previous studies, and place an upper limit on the ADF for O${}^{2+}$ of 35, significantly lower than that of the polar knots. These findings further reinforce the theory that the equatorial and polar knots originate from different events.

3 pages, 1 figure

References in corpus (6)

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Cited by in corpus (2)

• Common envelope evolution in born-again planetary nebulae -- Shaping the H-deficient ejecta of A30
• A primer on the formation and evolution of hydrogen deficient Central Stars of Planetary Nebulæ and Related Objects