Echelle measurements of the electron temperature of the giant halo of the planetary nebula NGC 6543

In a current programme at the Molonglo Radio Observatory using the high-resolution pencil beam of the instrument (∼3′ arc) an attempt is being made to extend the measured spectra of known planetary nebulae down to 408 MHz. Of 23 such planetaries already investigated, 14 have been detected. The main results will be given elsewhere; here it is proposed to discuss in detail only the well-known planetary nebula IC 418.

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SOFIA observations of the planetary nebula NGC 7009

Proceedings of the International Astronomical Union ◽

10.1017/s174392131201071x ◽

2011 ◽

Vol 7 (S283) ◽

pp. 67-70

Author(s):

R. H. Rubin ◽

S. W. J. Colgan ◽

R. L. M. Corradi ◽

R. Sankrit ◽

A. G. G. M. Tielens ◽

...

Keyword(s):

Fine Structure ◽

Electron Temperature ◽

Planetary Nebula ◽

Central Star ◽

Optical Measurements ◽

Optical Line

AbstractWe report spectrophotometric observations made with SOFIA/FORCAST on 2011 June 2 UT. Optical measurements have previously shown that the abundance discrepancy factor (adf) varies with position in several high-adf PNe, and is highest close to the central star. The very low electron temperature inclusions postulated to explain the abundance discrepancy, must be cooled predominantly by fine structure IR lines. These SOFIA data will map mid-IR FS lines (and our related Herschel program will add several far-IR FS lines) in the bright, well-characterized, high-adf PN NGC 7009. We will compare these IR results with FS optical line measurements in order to correlate ratios of IR to optical fluxes with position, and thus correlate with where the adf peaks.

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The Proto-Planetary Nebula Vy 2-2

Symposium - International Astronomical Union ◽

10.1017/s0074180900138835 ◽

1989 ◽

Vol 131 ◽

pp. 443-443 ◽

Cited By ~ 1

Author(s):

R. E. S. Clegg ◽

M. G. Hoare ◽

J. R. Walsh

Keyword(s):

Ir Spectroscopy ◽

Electron Temperature ◽

Empirical Analysis ◽

Planetary Nebula ◽

Black Body ◽

Central Star ◽

Speckle Interferometry ◽

Maser Emission ◽

Near Ir ◽

Carbon Abundance

High and low-resolution optical and near-IR spectroscopy of the candidate proto-planetary (or very young PN) Vy 2-2 (P-K 45 - 2°1) is reported. This object has associated OH maser emission and an angular diameter of only 0.4 arcsec, found from VLA and optical speckle interferometry. Empirical analysis gives the values Ne ≈3 × 105 cm−3, Te=11000(±1500)K. The electron temperature is quite uncertain because of the high density. Abundances of He, C, N, O, Ne and Ar are reported; the carbon abundance is uncertain as it relies on the C II λ4267Å line, since the object is too highly-reddened (c=1.8 ± 0.2) to be observed with IUE. We find He/H=0.10, O/H=4 × 10−4 and C/O=0.8. The HI Zanstra temperature is 38 000 K (for black-body). The spectrum shows broad stellar lines of He II λ4686, C III λ4647 and N III λ4640; the central star may be of type Of.

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Temperature Variations from HST Imagery and Spectroscopy of NGC 7009

Symposium - International Astronomical Union ◽

10.1017/s0074180900209017 ◽

2003 ◽

Vol 209 ◽

pp. 361-362

Author(s):

R. H. Rubin ◽

N. J. Bhatt ◽

R. J. Dufour ◽

B. A. Buckalew ◽

M. J. Barlow ◽

...

Keyword(s):

Electron Temperature ◽

Spatial Resolution ◽

Planetary Nebula ◽

Heavy Element ◽

High Spatial Resolution ◽

Flux Ratio ◽

Mean Square ◽

Temperature Variations ◽

Element Abundances ◽

Intrinsic Flux

We obtained new HST/STIS long-slit spectra and WFPC2 imagery of the planetary nebula NGC 7009 in order to obtain high spatial resolution of the intrinsic flux ratio [O III] 4364/5008, which is a well-known diagnostic for electron temperature (Te). Our primary purpose was to quantify Te variations across the nebula. We address whether the observational data support the possibility that the [fractional] mean-square Te variation (t2) (Peimbert 1967) in NGC 7009 may be as large as ~0.1. Such large values are required to reconcile the “abundance dichotomy” by Te variations alone. The abundance dichotomy (discussed by Liu at greater length elsewhere in this volume) refers to the significantly higher heavy element abundances derived from optical recombination lines (e.g., a factor of ~5 for NGC 7009, Liu et al. 1995) compared with the corresponding values deduced from collisionally-excited lines.

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The Electron Temperature in the Planetary Nebula IC 418

Publications of the Astronomical Society of the Pacific ◽

10.1086/126568 ◽

1953 ◽

Vol 65 ◽

pp. 161 ◽

Cited By ~ 3

Author(s):

R. Minkowski

Keyword(s):

Electron Temperature ◽

Planetary Nebula

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On the variations of [OIII] lines intensities in the spectrum of PN IC 4997

Symposium - International Astronomical Union ◽

10.1017/s0074180900131067 ◽

1997 ◽

Vol 180 ◽

pp. 289-289

Author(s):

A. G. Yeghikyan

Keyword(s):

Mass Loss ◽

Electron Temperature ◽

Effective Temperature ◽

Stellar Wind ◽

Planetary Nebula ◽

Loss Rate ◽

Mass Loss Rate ◽

Radiation Fields ◽

Ionization Structure ◽

Ionization Model

The causes of asynchronous variations of the intensities of OIII ions forbidden lines in the spectrum of compact planetary nebula IC 4997 are considered on the basis of the observational data of. It is shown that the rise of the intensity of line 4363 å and decrease of the intensities of N1 and N2 lines may be best explained by increase of mass-loss-rate from nucleous from 5 × 10–8 up to 2 × 10–7 M/yr within a few years (at constant nucleous effective temperature), with appropriate change of ionization structure of nebula. The arguments of existence of variable hot stellar wind are discussed. The theoretical intensities of lines are calculated by the ionization model of planetary nebulae [4], gyven the radiation fields of the nucleous and hot stellar wind with electron temperature Te= 500000 K.

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The ionization state of the halo planetary nebula NGC 2438

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312011313 ◽

2011 ◽

Vol 7 (S283) ◽

pp. 338-339

Author(s):

Silvia Dalnodar

Keyword(s):

Electron Temperature ◽

Electron Density ◽

Planetary Nebula ◽

Filling Factor ◽

Narrow Band ◽

Central Star ◽

Emission Lines ◽

Ionization State ◽

Hydrodynamic Simulations ◽

Slit Scanning

AbstractNGC 2438 is a classical multiple shell or halo planetary nebula (PN). Its central star and the main nebula are well studied. Also it was target of various hydrodynamic simulations (Corradi et al. 2000). This initiated a discussion whether the haloes are mainly containing recombined gas (Schönberner et al. 2002), or if they are still ionized (Armsdorfer et al. 2003). An analysis of narrow-band images and long slit spectra at multiple slit positions was done to obtain a deeper look on morphological details and the properties of the outer shell and halo. For this work there was data available from ESO (direct imaging and long slit spectroscopy) and from SAAO (spectroscopic observations using a small slit, scanning over the whole nebula). Using temperature measurements from emission lines resulted in an electron temperature which clearly indicates a fully ionized stage. Additionally measurements of the electron density suggest a variation of the filling factor.

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