The Herschel Planetary Nebula Survey (HerPlaNS) I. Data overview and analysis demonstration with NGC 6781
Journal article, 2014

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 (T-e, n(e)) 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-circle dot, consisting of 0.54 M-circle dot of ionized gas, 0.12 M-circle dot of atomic gas, 0.2 M-circle dot of molecular gas, and 4 x 10(-3) M-circle dot of dust grains. These estimates' also suggest that the central star of about 1.5 M-circle dot 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.

planetary nebulae

planetary nebulae: general

stars: mass-loss

stars: winds


infrared: stars


T. Ueta

University of Denver

JAXA Institute of Space and Astronautical Science

D. Ladjal

University of Denver

K. M. Exter

KU Leuven

M. Otsuka

Academia Sinica

R. Szczerba

Polish Academy of Sciences

N. Siodmiak

Polish Academy of Sciences

I. Aleman

Leiden University

P. A. M. van Hoof

Royal Observatory of Belgium

J. H. Kastner

Rochester Institute of Technology

R. Montez

Vanderbilt University

I. McDonald

Jodrell Bank Centre for Astrophysics

M. Wittkowski

European Southern Observatory (ESO)

C. Sandin

Leibniz Institute for Astrophysics Potsdam

S. Ramstedt

Uppsala University

O. De Marco

Macquarie University

E. Villaver

Universidad Autonoma de Madrid (UAM)

Y. H. Chu

University of Illinois

Wouter Vlemmings

Chalmers, Earth and Space Sciences, Onsala Space Observatory

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

H. Izumiura

National Astronomical Observatory of Japan

R. Sahai

Jet Propulsion Laboratory, California Institute of Technology

J. A. Lopez

Universidad Nacional Autonoma de Mexico

B. Balick

University of Washington

A. Zijlstra

Jodrell Bank Centre for Astrophysics

Aggm Tielens

Leiden University

R. E. Rattray

University of Denver

E. Behar

Technion – Israel Institute of Technology

E. G. Blackman

University of Rochester

K. Hebden

Jodrell Bank Centre for Astrophysics

J. L. Hora

Harvard-Smithsonian Center for Astrophysics

K. Murakawa

University of Leeds

J. Nordhaus

Rochester Institute of Technology

R. Nordon

Max Planck Society

I. Yamamura

JAXA Institute of Space and Astronautical Science

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 565 A36

Subject Categories

Astronomy, Astrophysics and Cosmology



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