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

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 O2+ 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.

Tailoring Molecular Weight of Polymer Additives for Organic Semiconductors

A binary system comprising both an organic semiconductor and a polymer additive has attracted extensive research interests due to great potential for high-performance, solution-proccessable electronic devices on flexible substrates. The...