IMAGING THE ELUSIVE H-POOR GAS IN THE HIGH adf PLANETARY NEBULA NGC 6778

Journal Article · Mon Jun 20 04:00:00 EDT 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/824/2/L27· OSTI ID:22654292

García-Rojas, Jorge; Corradi, Romano L. M.; Jones, David; Rodríguez-Gil, Pablo; Cabrera-Lavers, Antonio ^[1]; Monteiro, Hektor ^[2]

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1. Instituto de Astrofísica de Canarias, E-38200, La Laguna, Tenerife (Spain)
2. Instituto de Física e Química, Universidade Federal de Itajubá, Av. BPS 1303-Pinheirinho, 37500-903, Itajubá (Brazil)

We present the first direct image of the high-metallicity gas component in a planetary nebula (NGC 6778), taken with the OSIRIS Blue Tunable Filter centered on the O ii λ 4649+50 Å optical recombination lines (ORLs) at the 10.4 m Gran Telescopio Canarias. We show that the emission of these faint O ii ORLs is concentrated in the central parts of the planetary nebula and is not spatially coincident either with emission coming from the bright [O iii] λ 5007 Å collisionally excited line (CEL) or the bright H α recombination line. From monochromatic emission line maps taken with VIMOS at the 8.2 m Very Large Telescope, we find that the spatial distribution of the emission from the auroral [O iii] λ 4363 line resembles that of the O ii ORLs but differs from nebular [O iii] λ 5007 CEL distribution, implying a temperature gradient inside the planetary nebula. The centrally peaked distribution of the O ii emission and the differences with the [O iii] and H i emission profiles are consistent with the presence of an H-poor gas whose origin may be linked to the binarity of the central star. However, determination of the spatial distribution of the ORLs and CELs in other PNe and a comparison of their dynamics are needed to further constrain the geometry and ejection mechanism of the metal-rich (H-poor) component and hence, understand the origin of the abundance discrepancy problem in PNe.

• OSTI ID: 22654292
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 824; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
COMPARATIVE EVALUATIONS
EMISSION
FILTERS
METALLICITY
MONOCHROMATIC RADIATION
PLANETARY NEBULAE
RECOMBINATION
SPATIAL DISTRIBUTION
STARS
TELESCOPES
TEMPERATURE GRADIENTS