Planetary nebulae

Khromov, G.S.

doi:10.1007/bf00172024

Cited by 15 publications

(11 citation statements)

References 13 publications

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“…More than 1500 PNe have been discovered in the Galaxy to date. However, the estimates of their total number N tot differ significantly, from 4 × 10 3 to 4 × 10 5 : 4000-22 000 (Alloin et al 1976), 10000 ± 4000 (Jacoby 1980), 40000 (Amnuel et al 1984), > 10 5 (Ishida and Weinberger 1987), (2 − 4) × 10 5 (Khromov 1989), 7200 ± 1800 (Peimbert 1990), 23000 ± 6000 (Zijlstra and Pottasch 1991), 46000 ± 13000 (Moe and Marco 2006), or 24000 ± 4000 (Frew 2008).…”

Section: Introductionmentioning

confidence: 99%

Vertical distribution and kinematics of planetary nebulae in the milky way

Бобылев

Bajkova

2017

Astron. Lett.

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Based on published data, we have produced a sample of planetary nebulae (PNe) that is complete within 2 kpc of the Sun. We have estimated the total number of PNe in the Galaxy from this sample to be 17000 ± 3000 and determined the vertical scale height of the thin disk based on an exponential density distribution to be 197 ± 10 pc. The next sample includes PNe from the Stanghellini-Haywood catalog with minor additions. For this purpose, we have used ∼200 PNe with Peimbert's types I, II, and III. In this case, we have obtained a considerably higher value of the vertical scale height that increases noticeably with sample radius. We have experimentally found that it is necessary to reduce the distance scale of this catalog approximately by 20%. Then, for example, for PNe with heliocentric distances less than 4 kpc the vertical scale height is 256 ± 12 kpc. A kinematic analysis has confirmed the necessity of such a reduction of the distance scale.

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Section: Introductionmentioning

confidence: 99%

Vertical distribution and kinematics of planetary nebulae in the milky way

Бобылев

Bajkova

2017

Astron. Lett.

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“…In this way, we were able to make a direct comparison of the observed emissivity profiles to the modeled ones. Abundances were set in the Cloudy model to that of a typical metal rich PN as incorporated in the model code from Aller & Czyzak (1983) and Khromov (1989). An assumed GAIA DR2 distance of 1.3 kpc was used.…”

Section: Cloudy Modelmentioning

confidence: 99%

Planetary nebula IC 5148 and its ionized halo

Barría

Kimeswenger

Kausch

et al. 2018

A&A

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Context. Many round or nearly roundish Planetary Nebulae (PNe) show multiple shells and halo structures during their evolutionary stage near the maximum temperature of their central star. Controversial debate is currently ongoing if these structures are recombination halos, as suggested by hydrodynamic modelling efforts, or ionized material. Recently we discovered a halo with even somewhat unusual structures around the sparsely studied PN IC 5148 and present for the first time spectroscopy going out to the halo of such a PN. Aims. We investigate the spatial distribution of material and its ionization state from the center of the nebula up to the very outskirts of the halo. Methods. We obtained long-slit low resolution spectroscopy (FORS2@VLT) of the nebula in two position angles, which we used to investigate the nebular structure and its halo in the optical range from 450 to 880 nm. In addition we used medium resolution spectra taken with X-SHOOTER@VLT ranging from 320 nm to 2.4 µm to derive atmospheric parameters for the central star. We obtained the distance and position in the Galaxy from various methods combined with GAIA DR2 data. We also applied Cloudy models to the nebula in order to derive physical parameters of the various regions. Results. We obtained spatially resolved structures and detailed descriptions of the outrunning shock front and a set of unusual halo structures denoted to further shock. The halo structures appears clearly as hot ionized material. Furthermore we derived a reliable photometric value for the central star at a GAIA distance of D = 1.3 kpc. Considering the large distance z = 1.0 kpc from the galactic plane together to its non-circular motion in the galaxy and, a metallicity only slightly below that of typical disk PNe, most likely IC 5148 originates from a thick disk population star.

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“…Element abundances for He, O, N and S were also adjusted during the analysis. Due to lacking images in other element species, the remaining abundances were set in Cloudy to the typical PN element abundance taken from Aller & Czyzak (1983) and Khromov (1989). At Figures 6, 7 and 8 are displayed the best Cloudy model fitted to the observations.…”

Section: [O Iii]/hα Line Ratiosmentioning

confidence: 99%

HST/WFPC2 imaging analysis and cloudy modelling of the multiple-shell planetary nebulae NGC 3242, NGC 6826, and NGC 7662

Barría

Kimeswenger

2018

Monthly Notices of the Royal Astronomical Society

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We performed a detailed photometric analysis and photoionisation modelling on three high excitation multiple shell planetary nebulae: NGC 3242, NGC 6826 and NGC 7662. Archival HST/WFPC2 narrow band filter images were used to investigate shocked regions by two independent methods: using low excitation ions (via Hα/[N ii] vs Hα/[S ii] extended diagnostic diagrams) and by means of high excitation species looking for regions of enhanced [O iii]/Hα line ratios. Shocked region analysis via low excitation ions shows that major deviations from the general inside to outside ionisation trend correspond only to regions where FLIERs or LISs are located. The reduction on the SNR at the outskirts of the [O iii]/Hα ratio maps, made us unable to unambiguously identified for an enhancement on the [O iii]/Hα line ratio as an indicator for shocks. For non-shocked regions we performed a photoionisation modelling using Cloudy. Fittings to the [O iii] and Hα observed radial profiles lead us to constrain on the free parameters of the density laws and filling factors together to temperatures and luminosities for the CSPNe. Best fit models show a very well representation of the [O iii] and Hα emission. Discrepancies in the model fittings to the [N ii] and [S ii] profiles at NGC 6826 and NGC 3242, can be attributed in the former case, due to a contamination by the light of the CSPN and, in the latter case, either due to gas inhomogeneities within the clumps or to a leaking of UV radiation.

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Planetary nebulae

Cited by 15 publications

References 13 publications

Vertical distribution and kinematics of planetary nebulae in the milky way

Vertical distribution and kinematics of planetary nebulae in the milky way

Planetary nebula IC 5148 and its ionized halo

HST/WFPC2 imaging analysis and cloudy modelling of the multiple-shell planetary nebulae NGC 3242, NGC 6826, and NGC 7662

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