Chemical abundances in seven galactic planetary nebulae

Krabbe, Â. C.; Copetti, M. V. F.

doi:10.1051/0004-6361:20054112

Cited by 20 publications

(24 citation statements)

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“…We point out that the wavelength coverage as well as the region covered by the slit/aperture vary in the literature. Krabbe & Copetti (2006) data covering the wavelength range from 3100 Å to 6900 Å, is closer to ours not only in terms of spectral coverage, but also in terms of the elemental abundances and ICFs derived although they use a single slit. Similar to our studie, their study was based on optical spectra alone.…”

Section: Ionic and Total Chemical Abundancessupporting

confidence: 60%

Spatially resolved physical and chemical properties of the planetary nebula NGC 3242

Monteiro

Gonçalves

Leal-Ferreira

et al. 2013

A&A

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Aims. Optical integral-field spectroscopy was used to investigate the planetary nebula NGC 3242. We analysed the main morphological components of this source, including its knots, but not the halo. In addition to revealing the properties of the physical and chemical nature of this nebula, we also provide reliable spatially resolved constraints that can be used for future photoionisation modelling of the nebula. The latter is ultimately necessary to obtain a fully self-consistent 3D picture of the physical and chemical properties of the object. Methods. The observations were obtained with the VIMOS instrument attached to VLT-UT3. Maps and values for specific morphological zones for the detected emission-lines were obtained and analysed with routines developed by the authors to derive physical and chemical conditions of the ionised gas in a 2D fashion. Results. We obtained spatially resolved maps and mean values of the electron densities, temperatures, and chemical abundances for specific morphological structures in NGC 3242. These results show the pixel-to-pixel variations of the the small-and large-scale structures of the source. These diagnostic maps provide information free from the biases introduced by traditional single long-slit observations. Conclusions. In general, our results are consistent with a uniform abundance distribution for the object, whether we look at abundance maps or integrated fluxes from specified morphological structures. The results indicate that special care should be taken with the calibration of the data and that only data with extremely good signal-to-noise ratio and spectral coverage should be used to ensure the detection of possible spatial variations.

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Section: Ionic and Total Chemical Abundancessupporting

confidence: 60%

Spatially resolved physical and chemical properties of the planetary nebula NGC 3242

Monteiro

Gonçalves

Leal-Ferreira

et al. 2013

A&A

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“…In PNe, these estimatives show high values. As examples, Liu et al (2006) found t 2 ≈ 0.14 for Hf 2-2, and Krabbe & Copetti (2006) found t 2 ≈ 0.09 for NGC 3242 and NGC 7009 to obtain consistent O ++ /H + estimates derived from RLs and CELs. A discrete estimation of t 2 on the plane of the sky can be computed from point-to-point measurements of temperature, following the procedure proposed by Liu (1998).…”

Section: Magnitude Of the Electron Temperature Fluctuationsmentioning

confidence: 77%

Spectroscopic mapping of the planetary nebula NGC 6302

Rauber

Copetti

Krabbe

2014

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Context. Most spectroscopic studies of planetary nebulae (PNe) are based on data from specific parts of the objects. Considering the high complexity of their morphological structures, integrated or average values across an observed region can only provide limited information of their ionic, density, and temperature structures. Aims. We investigate the spatial variation of the physical and chemical properties of NGC 6302, a high-ionization PNe, with a complex bipolar structure. Methods. Spatially resolved long-slit spectroscopic data were obtained from 11 parallel and equally spaced directions over the nebula. Integrated spectra were also obtained and 142 lines were identified. Results. The electron density maps show a peaked distribution, with the densest area at the circumstellar region, reaching N e ≈ 40 000 cm −3 , and decreasing to N e ≤ 1000 cm −3 at the lobes. Knots were observed in the N e (S ii) map, with 2000 cm −3 < N e < 3000 cm −3 . The N e (Ar iv) map suggests the presence of an inner region with N e ≈ 20 000 cm −3 that extends from the center through the east lobe. A homogeneous temperature distribution was found for both T e (O iii) and T e (N ii). Small temperature fluctuations on the plane of the sky of t 2 s (N ii) = 0.0071 and t 2 s (O iii) = 0.0043 were estimated.Conclusions. In general, the total abundances obtained are similar to the maximum found in the ionic abundance maps of the dominant ionic species. This demonstrates the potential of spatially resolved abundance studies for establishing lower limits of the total abundances based on ionic abundances, for checking the ionization correlation factors, and in some cases, for determining the total abundances directly from maps of ionic abundances.

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“…Ionic metal abundances were obtained with the ionic routine of the nebular package of the STSDAS/IRAF. The references for atomic parameters used are listed in Table 2 of Krabbe & Copetti (2006). The ionic helium abundances were derived from the strongest lines λ4471, λ5876, and λ6678, using the He i emissivities of Benjamin et al (1999), which are corrected by the effects of collisional excitation.…”

Section: Electron Densities and Temperaturesmentioning

confidence: 99%

A study of the neglected Galactic H II region NGC 2579 and its companion ESO 370-9

Copetti¹,

Oliveira²,

Riffel

et al. 2007

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Context. The Galactic H ii region NGC 2579 has stayed undeservedly unexplored due to identification problems which persisted until recently. Both NGC 2579 and its companion ESO 370-9 have been misclassified as planetary or reflection nebula, confused with each other and with other objects. Due to its high surface brightness, high excitation, angular size of few arcminutes and relatively low interstellar extinction, NGC 2579 is an ideal object for investigations in the optical range. Located in the outer Galaxy, NGC 2579 is an excellent object for studying the Galactic chemical abundance gradients. Aims. To present the first comprehensive observational study on the nebular and stellar properties of NGC 2579 and ESO 370-9, including the determination of electron temperature, density structure, chemical composition, kinematics, distance, and the identification and spectral classification of the ionizing stars, and to discuss the nature of ESO 370-9. Methods. Long slit spectrophotometric data in the optical range were used to derive the nebular electron temperature, density and chemical abundances and for the spectral classification of the ionizing star candidates. Hα and UBV CCD photometry was carried out to derive stellar distances from spectroscopic parallax and to measure the ionizing photon flux. Results. The chemical abundances of He, N, O, Ne, S, Cl, and Ar were obtained. Maps of electron density and radial velocity with a spatial resolution of 5 × 5 were composed from long slit spectra taken at different declinations. Three O stars classified as O5 V, O6.5 V, and O8 V were found responsible for the ionization of NGC 2579, while ESO 370-9 is ionized by a single O8.5 V star. The estimated mass of ionized gas of ≈25 M indicates that ESO 370-9 is not a planetary nebula, but a small H ii region. A photometric distance of 7.6 ± 0.9 kpc and a kinematic distance of 7.4 ± 1.4 kpc were obtained for both objects. At the galactocentric distance of 12.8 ± 0.7 kpc, NGC 2579 is one of the most distant Galactic H ii regions for which direct abundance determinations have been accomplished. Key words. ISM: H ii regions -ISM: planetary nebulae: general IntroductionDue to observational difficulties, the knowledge acquisition in many research areas of astrophysics has still relied largely on data obtained from a small group of characteristic objects. This is certainly the case of the optical studies of Galactic H ii regions. In this field, the Orion Nebula is by far the most studied object. In fact, the number of papers on this object is comparable to the total number of optical studies of all other Galactic H ii regions. Even the standard procedure of measuring the electron temperature in Galactic H ii regions from optical emission line ratios, such as [O iii] (λ4959 + λ5007)/λ4363 and [N ii] (λ6548 + λ6584)/λ5755, until now could only be accomplished in a small sample of a dozen or so objects. So, the addition of new members to the selected list of well studied (or easy to observe) objects is welcome, especially becaus...

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Chemical abundances in seven galactic planetary nebulae

Cited by 20 publications

References 50 publications

Spatially resolved physical and chemical properties of the planetary nebula NGC 3242

Spatially resolved physical and chemical properties of the planetary nebula NGC 3242

Spectroscopic mapping of the planetary nebula NGC 6302

A study of the neglected Galactic H II region NGC 2579 and its companion ESO 370-9

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