PAH and nbL Features Detection in Planetary Nebulae NGC 7027 and BD +303639 with TIRCAM2 Instrument on 3.6m DOT

TL;DR

This study presents high-resolution infrared imaging of planetary nebulae NGC 7027 and BD +303639 using TIRCAM2 on the 3.6m DOT, revealing PAH and dust features and morphological details in multiple infrared bands.

Contribution

First observations of these nebulae in PAH and nbL bands with TIRCAM2 on DOT, providing new insights into their morphology and PAH ionization states.

Findings

NGC 7027 shows elliptical morphology with multipolar evolution.

BD +303639 exhibits a rectangular-ring shape with neutral PAHs.

PAH emission detected at thousands of AU from central stars.

Abstract

High resolution infrared imaging observations of the young Planetary Nebulae NGC 7027 and BD +303639, taken with the newly installed TIFR Infrared Camera-II (TIRCAM2) on 3.6m Devasthal Optical Telescope (DOT), ARIES, Nainital, are being reported. The images are acquired in J, H, K, polycyclic aromatic hydrocarbon (PAH) and narrow-band L (nbL) filters. The observations show emission from warm dust and PAHs in the circumstellar shells. The imaging of the two objects are among the first observations in PAH and nbL bands using TIRCAM2 on DOT. The NGC 7027 images in all bands show similar elliptical morphology with ~6".7 and ~4".5 semi-major and semi-minor axes. Considering size up to 10% of peak value the nebula extends upto 8" from the central star revealing a multipolar evolution. The relatively cooler BD +303639 shows a rectangular-ring shaped nebula. In J and H bands it shows an angular diameter of ~8", while a smaller ~6".9 size is observed in K, PAH and nbL bands. The 3.28 micron emission indicates presence of PAHs at about 6000 and 5000 AU from the central stars in NGC 7027 and BD +303639 respectively. Analysis suggests domination of neutral PAHs in BD+303639, while in NGC 7027 there is higher ionization and more processed PAH population.