A multiwavelength study of the PN Hen 3-1357 (Stingray Nebula); properties of the nebula, central star, and dust

Masaaki Otsuka, M. Parthasarathy, A. Tajitsu, S. Hubrig & G. Sarkar

Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan

We performed chemical abundance analysis and photo-ionisation modeling of a young planetary nebula (PN) Hen3-1357 based on spectra from the MPG ESO 2.2-m/FEROS and Spitzer/IRS and photometry from the Spitzer/IRAC and AKARI/FIS in order to more characterize this PN. We calculated the nebular He/C/N/O/Ne/S/Cl/Ar/Fe abundances using collisionally excited lines (CELs) and recombination lines (RLs). We report the first measurements of the RL N and O abundances in this object. The RL C/O ratio (0.20) indicates that this PN is O-rich, which is supported by the detection of the amorphous silicate's broad features at 9-um due to the Si-O stretching mode and at 18-um due to the O-Si-O bending mode. The C/O and N/O (0.1) ratios suggest that this PN has evolved from a 1-2 solar mass star. By fitting the observed data using the photo-ionisation code CLOUDY and O-star grid models by TLUSTY, we investigated properties of the central star and derived the gas and dust masses. The nebular elemental abundances and the core-mass of the central star are in good agreement with the AGB star model of the initially 1.5 solar mass stars with Z=0.008.

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