TY - JOUR
T1 - The Herschel planetary nebula survey (HerPlaNS)
T2 - I. Data overview and analysis demonstration with NGC? 6781
AU - Ueta, T.
AU - Ladjal, D.
AU - Exter, K. M.
AU - Otsuka, M.
AU - Szczerba, R.
AU - Siódmiak, N.
AU - Aleman, I.
AU - Van Hoof, P. A.M.
AU - Kastner, J. H.
AU - Montez, R.
AU - McDonald, I.
AU - Wittkowski, M.
AU - Sandin, C.
AU - Ramstedt, S.
AU - De Marco, O.
AU - Villaver, E.
AU - Chu, Y. H.
AU - Vlemmings, W.
AU - Izumiura, H.
AU - Sahai, R.
AU - Lopez, J. A.
AU - Balick, B.
AU - Zijlstra, A.
AU - Tielens, A. G.G.M.
AU - Rattray, R. E.
AU - Behar, E.
AU - Blackman, E. G.
AU - Hebden, K.
AU - Hora, J. L.
AU - Murakawa, K.
AU - Nordhaus, J.
AU - Nordon, R.
AU - Yamamura, I.
N1 - Funding Information:
This work is based on observations made with the Herschel Space Observatory, a European Space Agency (ESA) Cornerstone Mission with significant participation by NASA. Support for this work was provided by NASA through an award issued by Jet Propulsion Laboratory, Caltech (Ueta, Ladjal, Kastner, Sahai), the Japan Society for the Promotion of Science (JSPS) through a FY2013 long-term invitation fellowship program (Ueta), the Belgian Federal Science Policy Office via the PRODEX Programme of ESA (Exter, van Hoof), the Polish NCN through a grant 2011/01/B/ST9/02031 (Szczerba, Siódmiak), and the European Research Council via the advanced-ERC grant 246976 and the Dutch Science Agency (NWO) via the Dutch Astrochemistry Network and the Spinoza prize (Aleman, Tielens). The authors thank M. A. Guerrero for sharing the NOT optical images of NGC 6781 with us. Also, H. Monteiro’s generosity is appreciated for the reproduction of one of his figures (Fig. 3 of Schwarz & Monteiro 2006). Sahai acknowledges that his contribution to the research described here was carried out at the JPL/Caltech, under a contract with NASA. Finally, Ueta also acknowledges the hospitality of the members of the Laboratory of Infrared Astrophysics at ISAS/JAXA during his sabbatical stay as a JSPS invitation fellow.
PY - 2014/5
Y1 - 2014/5
N2 - Context. This is the first of a series of investigations into far-IR characteristics of 11 planetary nebulae (PNe) under the Herschel Space Observatory open time? 1 program, Herschel Planetary Nebula Survey (HerPlaNS). Aims. Using the HerPlaNS data set, we look into the PN energetics and variations of the physical conditions within the target nebulae. In the present work, we provide an overview of the survey, data acquisition and processing, and resulting data products. Methods. We performed (1) PACS/SPIRE broadband imaging to determine the spatial distribution of the cold dust component in the target PNe and (2) PACS/SPIRE spectral-energy-distribution and line spectroscopy to determine the spatial distribution of the gas component in the target PNe. Results. For the case of NGC? 6781, the broadband maps confirm the nearly pole-on barrel structure of the amorphous carbon-rich dust shell and the surrounding halo having temperatures of 26-40? K. The PACS/SPIRE multiposition spectra show spatial variations of far-IR lines that reflect the physical stratification of the nebula. We demonstrate that spatially resolved far-IR line diagnostics yield the (Te, ne) profiles, from which distributions of ionized, atomic, and molecular gases can be determined. Direct comparison of the dust and gas column mass maps constrained by the HerPlaNS data allows to construct an empirical gas-to-dust mass ratio map, which shows a range of ratios with the median of 195 ± 110. The present analysis yields estimates of the total mass of the shell to be 0.86? M?, consisting of 0.54? M? of ionized gas, 0.12? M? of atomic gas, 0.2? M? of molecular gas, and 4 × 10-3? M? of dust grains. These estimates also suggest that the central star of about 1.5? M? initial mass is terminating its PN evolution onto the white dwarf cooling track. Conclusions. The HerPlaNS data provide various diagnostics for both the dust and gas components in a spatially resolved manner. In the forthcoming papers of the HerPlaNS series we will explore the HerPlaNS data set fully for the entire sample of 11 PNe.
AB - Context. This is the first of a series of investigations into far-IR characteristics of 11 planetary nebulae (PNe) under the Herschel Space Observatory open time? 1 program, Herschel Planetary Nebula Survey (HerPlaNS). Aims. Using the HerPlaNS data set, we look into the PN energetics and variations of the physical conditions within the target nebulae. In the present work, we provide an overview of the survey, data acquisition and processing, and resulting data products. Methods. We performed (1) PACS/SPIRE broadband imaging to determine the spatial distribution of the cold dust component in the target PNe and (2) PACS/SPIRE spectral-energy-distribution and line spectroscopy to determine the spatial distribution of the gas component in the target PNe. Results. For the case of NGC? 6781, the broadband maps confirm the nearly pole-on barrel structure of the amorphous carbon-rich dust shell and the surrounding halo having temperatures of 26-40? K. The PACS/SPIRE multiposition spectra show spatial variations of far-IR lines that reflect the physical stratification of the nebula. We demonstrate that spatially resolved far-IR line diagnostics yield the (Te, ne) profiles, from which distributions of ionized, atomic, and molecular gases can be determined. Direct comparison of the dust and gas column mass maps constrained by the HerPlaNS data allows to construct an empirical gas-to-dust mass ratio map, which shows a range of ratios with the median of 195 ± 110. The present analysis yields estimates of the total mass of the shell to be 0.86? M?, consisting of 0.54? M? of ionized gas, 0.12? M? of atomic gas, 0.2? M? of molecular gas, and 4 × 10-3? M? of dust grains. These estimates also suggest that the central star of about 1.5? M? initial mass is terminating its PN evolution onto the white dwarf cooling track. Conclusions. The HerPlaNS data provide various diagnostics for both the dust and gas components in a spatially resolved manner. In the forthcoming papers of the HerPlaNS series we will explore the HerPlaNS data set fully for the entire sample of 11 PNe.
KW - Circumstellar matter
KW - Infrared: stars
KW - Planetary nebulae: general
KW - Planetary nebulae: individual: NGC 6781
KW - Stars: mass-loss
KW - Stars: winds, outflows
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U2 - 10.1051/0004-6361/201423395
DO - 10.1051/0004-6361/201423395
M3 - Article
AN - SCOPUS:84899542525
SN - 0004-6361
VL - 565
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A36
ER -