THE DISCREPANT KINEMATICS OF ORLs AND CELs IN NGC 7009 AS A FUNCTION OF IONIZATION STRUCTURE

Richer, M. G.; Георгиев, Л.; Arrieta, A.; Torres-Peimbert, S.

doi:10.1088/0004-637x/773/2/133

Cited by 23 publications

(28 citation statements)

References 62 publications

(92 reference statements)

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“…In this sense we are finding the same results reported by Liu et a. (2000), Richer et al (2013) and García-Rojas et al (2016) for NGC 6153, NGC 7009 and NGC 6778 respectively, where ORLs are being mainly emitted in an inner zone than CELs. And that kinematics of ORLs is incompatible with that of CELs.…”

Section: Discussionsupporting

confidence: 93%

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The kinematical behavior of ORLs and CELs in PNe with [WC] central star

Peña¹,

Ruiz-Escobedo²,

Rechy-García

et al. 2016

Proc. IAU

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Abstract. In Planetary Nebulae (PNe) and HII regions ionic abundances can be derived by using collisionally excited lines (CELs) or recombination lines (ORLs). Such abundances do not coincide for the same ion and usually abundances from ORLs are larger than those from CELs by factors of 2 or larger. The origin of the discrepancy, known as the Abundance Discrepancy Factor is an open problem in astrophysics of gaseous nebulae. It has been attributed to temperature fluctuations in the plasma, tiny metal-rich inclusions embedded in the H-rich plasma, gas inhomogeneities or other processes. In this work we analyze the kinematical behavior of CELs and ORLs in two PNe ionized by [WC] stars, finding that kinematics of ORLS is incompatible with the kinematics of CELs. In particular the expansion velocities from CELs and ORLs for the same ion are different, indicating that ORLs seem to be produced in zones nearer the central star than CELs. This is in agreement with results found by other authors for individual PNe.

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Section: Discussionsupporting

confidence: 93%

“…More recently Richer et al (2013) analyzed in detail the spatially and velocity-resolved spectroscopy of ORLs and CELs for the same ion in NGC 7009, finding that the lines show discrepant kinematics and location. ORLs kinematics is incompatible with the ionization structure given by CELs.…”

Section: Introductionmentioning

confidence: 99%

The kinematical behavior of ORLs and CELs in PNe with [WC] central star

Peña¹,

Ruiz-Escobedo²,

Rechy-García

et al. 2016

Proc. IAU

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“…Moreover, the mechanisms producing, and allowing for the survival of, temperature fluctuations in a photoionized plasma are still under debate (Peimbert et al 2017), while the same is true for the physical origin of the metal-rich component (Stasińska et al 2007;Corradi et al 2015). Nevertheless, some observational evidence of the existence of two or more gaseous phases in PNe have been found by several authors in recent years (Wesson et al 2003;Liu et al 2006;Wesson et al 2008;Richer et al 2013Richer et al , 2017Peña et al 2017).…”

Section: Introductionmentioning

confidence: 99%

The impact of strong recombination on temperature determination in planetary nebulae

Gómez-Llanos¹,

Morisset²,

García‐Rojas

et al. 2020

Monthly Notices of the Royal Astronomical Society: Letters

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The long-standing difference in chemical abundances determined from optical recombination lines and collisionally excited lines raises questions about our understanding of atomic physics, as well as the assumptions made when determining physical conditions and chemical abundances in astrophysical nebulae. Here, we study the recombination contribution of [O iii] 4363 and the validity of the line ratio [O iii] 4363/4959 as a temperature diagnostic in planetary nebulae with a high abundance discrepancy. We derive a fit for the recombination coefficient of [O iii] 4363 that takes into account the radiative and dielectronic recombinations, for electron temperatures from 200 to 30,000 K. We estimate the recombination contribution of [O iii] 4363 for the planetary nebulae Abell 46 and NGC 6778 by subtracting the collisional contribution from the total observed flux. We find that the spatial distribution for the estimated recombination contribution in [O iii] 4363 follows that of the O ii 4649 recombination line, both peaking in the central regions of the nebula, especially in the case of Abell 46 which has a much higher abundance discrepancy. The estimated recombination contribution reaches up to 70% and 40% of the total [O iii] 4363 observed flux, for Abell 46 and NGC 6778, respectively.

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“…Since some years ago our group have started the analysis of several PNe to determine the physical conditions and chemistry in the ionized gas by using CELs and ORLs, by means of spectrophotometric data of high-and low-spectral resolution. In our previous work (Peña et al 2017) and in works by other authors, evidence of different plasmas, with different chemistry and spatial location, existing in some nebulae, has been reported: one plasma is more widespread, it has low metallicity and high electron temperature, and it emits mainly the CELs, the other has larger heavy-element abundances and lower electron temperature, it is more concentrated towards the inner nebular zone and produces mainly the ORLs (see, e.g., García-Rojas et al 2016;Richer et al 2013).…”

Section: Introductionmentioning

confidence: 91%

Abundance Discrepancy Factors in high density planetary nebulae

Ruiz-Escobedo,

Peña

2022

Preprint

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From high-resolution spectra, chemical abundances from collisionally excited lines (CELs) and optical recombination lines (ORLs) have been determined for planetary nebulae Cn 3-1, Vy 2-2, Hu 2-1, Vy 1-2 and IC 4997, which are young and dense objects. The main aim of this work is to derive their O +2 /H + Abundance Discrepancy Factors, ADFs, between CELs and ORLs. He, O, N, Ne, Ar, S, and Cl abundances were obtained and our values are in agreement with those previously reported. We found that Cn 3-1, Hu 2-1, and Vy 1-2 have O abundances typical of disc PNe, while Vy 2-2 and IC 4997 are low O abundance objects (12 + log(O/H) ∼ 8.2), which can be attributed to possible O depletion into dust grains. ADFs(O +2 ) of 4.30 +1.00 −1.16 , 1.85 ± 1.05, 5.34 +1.27 −1.08 and 4.87 +4.34 −2.71 were determined for Vy 2-2, Hu 2-1, Vy 1-2 and IC 4997, respectively. The kinematics of CELs and ORLs was analysed for each case to study the possibility that different coexisting plasmas in the nebula emit them. Expansion velocities of [O ] and O are equal within uncertainties in three PNe, providing no evidence for these lines being emitted in different zones. Exception are Hu 2-1 and Vy 2-2, where ORLs might be emitted in different zones than CELs. For Vy 2-2 and IC 4997 we found that nebular and auroral lines of the same ion (S + , N + , Ar +2 , Ar +3 , O +2 ) might present different expansion velocities. Auroral lines show lower V exp which might indicate that they are emitted in a denser and inner zone than the nebular ones.

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THE DISCREPANT KINEMATICS OF ORLs AND CELs IN NGC 7009 AS A FUNCTION OF IONIZATION STRUCTURE

Cited by 23 publications

References 62 publications

The kinematical behavior of ORLs and CELs in PNe with [WC] central star

The kinematical behavior of ORLs and CELs in PNe with [WC] central star

The impact of strong recombination on temperature determination in planetary nebulae

Abundance Discrepancy Factors in high density planetary nebulae

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