IRAS 17423-1755 (HEN 3-1475) REVISITED: AN O-RICH HIGH-MASS POST-ASYMPTOTIC GIANT BRANCH STAR

Journal Article · Tue Mar 15 00:00:00 EDT 2011 · Astronomical Journal (New York, N.Y. Online)

DOI:https://doi.org/10.1088/0004-6256/141/3/80· OSTI ID:21583210

Manteiga, M ^[1]; GarcIa-Hernandez, D A; Manchado, A ^[2]; Ulla, A ^[3]; GarcIa-Lario, P ^[4]

---

1. Departamento de Ciencias de la Navegacion y de la Tierra, Universidade da Coruna, Paseo de Ronda 51, E-15011 A Coruna (Spain)
2. Instituto de Astrofisica de Canarias (IAC), VIa Lactea s/n, E-38200 La Laguna, Tenerife (Spain)
3. Departamento de Fisica Aplicada, Campus Lagoas-Marcosende, Universidade de Vigo, E-36310 Vigo, Pontevedra (Spain)
4. Herschel Science Centre, European Space Astronomy Centre (ESAC)/European Space Agency (ESA), Villafranca del Castillo, Apartado de Correos 78, E-28080 Madrid (Spain)

The high-resolution (R {approx} 600) Spitzer/IRS spectrum of the bipolar protoplanetary nebula (PN) IRAS 17423-1755 is presented in order to clarify the dominant chemistry (C-rich versus O-rich) of its circumstellar envelope as well as to constrain its evolutionary stage. The high-quality Spitzer/IRS spectrum shows weak 9.7 {mu}m absorption from amorphous silicates. This confirms for the first time the O-rich nature of IRAS 17423-1755 in contradiction to a previous C-rich classification, which was based on the wrong identification of the strong 3.1 {mu}m absorption feature seen in the Infrared Space Observatory spectrum as due to acetylene (C{sub 2}H{sub 2}). The high-resolution Spitzer/IRS spectrum displays a complete lack of C-rich mid-IR features such as molecular absorption features (e.g., 13.7 {mu}m C{sub 2}H{sub 2}, 14.0 {mu}m HCN, etc.) or the classical polycyclic aromatic hydrocarbon infrared emission bands. Thus, the strong 3.1 {mu}m absorption band toward IRAS 17423-1755 has to be identified as water ice. In addition, an [Ne II] nebular emission line at 12.8 {mu}m is clearly detected, indicating that the ionization of its central region may be already started. The spectral energy distribution in the infrared ({approx}2-200 {mu}m) and other observational properties of IRAS 17423-1755 are discussed in comparison with the similar post-asymptotic giant branch (AGB) objects IRAS 19343+2926 and IRAS 17393-2727. We conclude that IRAS 17423-1755 is an O-rich high-mass post-AGB object that represents a link between OH/IR stars with extreme outflows and highly bipolar PN.

• OSTI ID: 21583210
• Journal Information: Astronomical Journal (New York, N.Y. Online), Vol. 141, Issue 3; Other Information: DOI: 10.1088/0004-6256/141/3/80; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
ACETYLENE
ENERGY SPECTRA
HYDROCYANIC ACID
ICE
IONIZATION
PLANETARY NEBULAE
POLYCYCLIC AROMATIC HYDROCARBONS
PROTOPLANETS
SILICATES
STARS
ALKYNES
AROMATICS
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INORGANIC COMPOUNDS
NEBULAE
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SORPTION
SPECTRA