Open AccessTwo new evolved bipolar planetary nebulae in the solar neighbourhood
Author(s) -
Frew David J.,
Parker Quentin A.,
Russeil Delphine
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.10898.x
Subject(s) - physics , astrophysics , brightness , stars , radius , surface brightness , ionization , astronomy , galaxy , ion , computer security , quantum mechanics , computer science
We present AAO/UKST Hα+[N ii ] narrow‐band imagery and low‐ and medium‐resolution optical spectroscopy of RCW 24 and RCW 69. These nebulae were previously classified as H ii regions, but we now show them to be two of the largest and nearest bipolar Type I PNe yet discovered. Distances were estimated using extinction–distance and kinematic methods, and via a new Hα surface brightness–radius relation. The adopted distances are 1.0 ± 0.3 kpc for RCW 24 and 1.3 ± 0.2 kpc for RCW 69. Both objects have enhanced nitrogen abundances, with log N/O ≃ +0.44 for RCW 24, and log N/O = +0.33 for RCW 69. Systemic velocities and | z | distances are V LSR =+5 km s −1 and | z | ∼ 23 pc for RCW 24, and V LSR =−33 km s −1 and only | z | ∼ 7 pc for RCW 69. Both PNe originated from massive progenitors (>2.0–2.5 M ⊙ ), as deduced from their chemical abundances, large ionized masses, small | z | distances, low peculiar velocities and relatively hot central stars. These two objects form an important addition to the small sample of evolved bipolar PNe in the solar neighbourhood.