Physical properties of the very young PN Hen3-1357 (Stingray Nebula)
  based on multiwavelength observations
  We have carried out a detailed analysis of the interesting and important very
young planetary nebula (PN) Hen3-1357 (Stingray Nebula) based on a unique
dataset of optical to far-IR spectra and photometric images. We calculated the
abundances of nine elements using collisionally excited lines (CELs) and
recombination lines (RLs). The RL C/O ratio indicates that this PN is O-rich,
which is also supported by the detection of the broad 9/18 um bands from
amorphous silicate grain. The observed elemental abundances can be explained by
asymptotic giant branch (AGB) nucleosynthesis models for initially 1-1.5 Msun
stars with Z = 0.008. The Ne overabundance might be due to the enhancement of
22Ne isotope in the He-rich intershell. By using the spectrum of the central
star synthesized by Tlusty as the ionization/heating source of the PN, we
constructed the self-consistent photoionization model with Cloudy to the
observed quantities, and we derived the gas and dust masses, dust-to-gas mass
ratio, and core-mass of the central star. About 80 % of the total dust mass is
from warm-cold dust component beyond ionization front. Comparison with other
Galactic PNe indicates that Hen3-1357 is an ordinary amorphous silicate rich
and O-rich gas PN. Among other studied PNe, IC4846 shows many similarities in
properties of the PN to Hen3-1357, although their post-AGB evolution is quite
different from each other. Further monitoring observations and comparisons with
other PNe such as IC4846 are necessary to understand the evolution of
Hen3-1357.
