Infrared observations of the helix planetary nebula

  title={Infrared observations of the helix planetary nebula},
  author={J. Hora and W. Latter and Howard A. Smith and M. Marengo},
  journal={The Astrophysical Journal},
We have mapped the Helix (NGC 7293) planetary nebula (PN) with the IRAC instrument on the Spitzer Space Telescope. The Helix is one of the closest bright PNs and therefore provides an opportunity to resolve the small-scale structure in the nebula. The emission from this PN in the 5.8 and 8 μm IRAC bands is dominated by the pure rotational lines of molecular hydrogen, with a smaller contribution from forbidden line emission such as [Ar III] in the ionized region. The IRAC images resolve the… Expand
VLT/near-infrared integral field spectrometer observations of molecular hydrogen lines in the knots of the planetary nebula NGC 7293 (the Helix Nebula)
Knots are commonly found in nearby planetary nebulae (PNe) and star-forming regions. Within PNe, knots are often found to be associated with the brightest parts of the nebulae and understanding theExpand
Herschel spectral mapping of the Helix nebula (NGC 7293) - Extended CO photodissociation and OH+ emission
Context. The Helix nebula (NGC 7293) is our closest planetary nebulae. Therefore, it is an ideal template for photochemical studies at small spatial scales in planetary nebulae. Aims. We aim toExpand
Herschel imaging of the dust in the Helix Nebula (NGC 7293)
In our series of papers presenting the Herschel imaging of evolved planetary nebulae, we present images of the dust distribution in the Helix nebula (NGC 7293). Images at 70, 160, 250, 350, and 500Expand
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We report the discovery of an extended halo (~40' in diameter) around the planetary nebula NGC?7293 (the Helix Nebula) observed in the 12 ?m band from the Wide-field Infrared Survey Explorer all-skyExpand
Determination of the Physical Conditions of the Knots in the Helix Nebula from Optical and Infrared Observations
We use new Hubble Space Telescope and archived images to clarify the nature of the ubiquitous knots in the Helix Nebula, which are variously estimated to contain a significant to majority fraction ofExpand
Optical line profiles of the Helix planetary nebula (NGC 7293) to large radii
New, very long (25 arcmin), cuts of spatially resolved profiles of the Hα and [N II] optical emission lines have been obtained over the face of the Helix planetary nebula, NGC 7293. These directionsExpand
On the relationship between the H2 emission and the physical structure of planetary nebulae
Mid-IR observations of planetary nebulae (PNe) have revealed diffuse emission associated to their main nebular shells and outer envelopes or haloes. The interpretation of this emission is uncertainExpand
Mid-infrared imaging of 18 planetary nebulae using the Spitzer Space Telescope
We present 3.6-, 4.5-, 5.8- and 8.0-μm photometric mapping of 18 galactic planetary nebulae, based on observations taken with the Spitzer Space Telescope. These are shown to have morphologies whichExpand
H2 infrared line emission from the ionized region of planetary nebulae
Context. The analysis and interpretation of the H2 line emission from planetary nebulae have been done in the literature by assuming that the molecule survives only in regions where the hydrogen isExpand
Modelling the warm H2 infrared emission of the Helix nebula cometary knots
Molecular hydrogen emission is commonly observed in planetary nebulae. Images taken in infrared H2 emission lines show that at least part of the molecular emission is produced inside the ionizedExpand


We present the initial results from the Infrared Array Camera (IRAC) imaging survey of planetary nebulae (PNs). The IRAC colors of PNs are red, especially in the 8.0 μm band. Emission in this band isExpand
The creation of the Helix planetary nebula (NGC 7293) by multiple events
A deep continuum-subtracted image of NGC 7293 has been obtained in the light of the Hα+[N ii] emission lines. New images of two filamentary halo structures have been obtained, and a possibleExpand
Large-Scale Extended Emission around the Helix Nebula: Dust, Molecules, Atoms, and Ions
We present new observations of the ionized gas, molecular gas, and cool dust in the Helix Nebula (NGC 7293). The ionized gas is observed in the form of an Himage, which is constructed using imagesExpand
A Multi-Instrument Study of the Helix Nebula Knots with the Hubble Space Telescope
We have conducted a combined observational and theoretical investigation of the ubiquitous knots in the Helix Nebula (NGC 7293). We have constructed a combined hydrodynamic + radiation model for theExpand
The Molecular Envelope of the Helix Nebula
We present a fully sampled map of the Helix Nebula in the 1.3 mm CO J = 2-1 line, made using the Caltech Submillimeter Observatory. The angular resolution is 31'', and the velocity resolution is 1.5Expand
The kinematics of the large western knot in the halo of the young planetary nebula NGC 6543
A detailed analysis of the dominant ionized knot in the halo of the planetary nebula NGC 6543 is presented. Observations were made at high spectral and spatial resolution of the [O iii]λ5007-A lineExpand
Dust in the neutral globules of the Helix nebula, NGC 7293
Images of the ionized knots and spokes within the helical structure of the Helix nebula have been obtained with subarcsecond resolution in the light of the Hα + [N II], [O III] 5007 A and [O II] 3727Expand
The Multitude of Molecular Hydrogen Knots in the Helix Nebula
We present Hubble Space Telescope NICMOS imaging of the H2 2.12 μm emission in five fields in the Helix Nebula ranging in radial distance from 250'' to 450'' from the central star. The images revealExpand
Morphology and composition of the helix nebula
We present new narrowband filter imagery in Hα and [N II] λ6584, along with UV and optical spectrophotometry measurements from 1200 to 9600 A of NGC 7293, the Helix Nebula, a nearby, photogenicExpand
Outflows from Massive Young Stellar Objects as Seen with the Infrared Array Camera
The bipolar outflow from the massive star-forming cluster in DR 21 is one of the most powerful known, and in IRAC images the outflow stands out by virtue of its brightness at 4.5 ?m (band 2). Indeed,Expand