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