A Survey of High-Frequency Radio Radiation from Planetary Nebulae

Kaftan-Kassim, M. A.

doi:10.1086/149882

Cited by 7 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Points in Fig. 5 represent observed data with flux densities taken from the literature (Menon & Terzian 1965;Slee & Orchiston 1965;Terzian 1966;Hughes 1967;Mezger et al 1967;Thompson et al 1967;Terzian 1968;Berge & Seielstad 1969;Kaftan-Kassim 1969;Le Marne 1969;Ribes 1969;Terzian 1969;Thomasson & Davies 1970; Table 1. Adopted input parameters for the fitting of the radio spectra.…”

Section: Comparing Calculated and Observed Radio Spectramentioning

confidence: 99%

Radio-continuum spectrum, brightness temperature, and planetary nebulae properties

Gruenwald¹,

Aleman²

2006

A&A

View full text Add to dashboard Cite

Context. Radio-continuum spectra are frequently used to infer the density distribution of ionized gaseous regions, while observed correlations between the brightness temperature and other distance-independent parameters are used to test evolutionary models of planetary nebulae. Aims. We check empirical correlations among features derived from the observed radio data and the inferred conclusions available in the literature, using self-consistent photoionization models. Methods. Photoionization models are computed for the physical conditions of planetary nebulae in order to derive self-consistent radio-continuum spectra, as well as the brightness temperature. Results. The temperature and ionization distributions throughout the nebulae explain the observed range of spectral indexes in the thick region of the spectrum, even for a uniform density distribution, usually challenged in the literature. The obtained models fit the observed radio spectra for planetary nebulae in a large range of spectral indexes. Our calculations show a correlation between the spectral index obtained in a given frequency range and the nebula size, as well as reproduce the observed relations between the brightness temperature and other distance-independent parameters. Such diagrams are frequently used to check evolutionary models of the central star and/or of the nebula. Conclusions. Since PNe images clearly show that the density is not constant inside the nebulae, and models with uniform and nonuniform density distributions can both reproduce the observed radio spectra, we conclude that it is not possible to favour one of them from the radio data, or to infer a particular density distribution for planetary nebulae.

show abstract

Section: Comparing Calculated and Observed Radio Spectramentioning

confidence: 99%

Radio-continuum spectrum, brightness temperature, and planetary nebulae properties

Gruenwald¹,

Aleman²

2006

A&A

View full text Add to dashboard Cite

show abstract

“…The interstellar extinction to NGC 1514 is given by Kaler (1976) as 0.74 mag, derived from H/3 and radio data, corresponding to E(B -V) = 0.50 mag. A more recent study by Kaler (1983) lists cVLß = 0.92±0.10 based on the optical data from Chopinet (1963) and 0.95 ±0.09 from radio data by Kaftan-Kassim (1969), while Pottasch (1984, pp. 101 and 157) lists E(B-V) = 0.45 and 0.50 from the X2200 interstellar extinction bump.…”

Section: Extinction and Stellar Temperaturesmentioning

confidence: 99%

The IUE Spectrum of the Binary Nucleus of the Planetary Nebula NGC 1514

Feibelman¹

1997

PASP

View full text Add to dashboard Cite

Archival IUE low-dispersion spectra and the first ultraviolet high-dispersion spectrum of the binary nucleus of NGC 1514 have been analyzed. Both SWP and LWR low-dispersion spectra show variability by as much as a factor of two in the continuum level between the years 1978 and 1989. Weak P Cygni features for O v XI371 and C IV XI549 yield terminal wind velocities of -105 ±25 and -960 ±150kms -1 , respectively. No nebular emission lines were detected, but several photospheric and interstellar absorption features were observed. Absorption lines of Fe vn are suspected. The Hen XI640 absorption line has a radial velocity of +49±3 km s -1 and is in good agreement with optical data. The peculiar energy distribution of the SWP continuum for NGC 1514 can be synthesized by the coaddition of spectral-type A0-A3 III plus hot subdwarf IUE spectra.

show abstract

“…(1) Davies et al (1965); (2) Menon & Terzian (1965); (3) Slee & Orchiston (1965); (4) Khromov (1966); (5) Terzian (1966); (6) Davies et al (1967); (7) Hughes (1967); (8) Thompson et al (1967); (9) Terzian (1968); (10) Kaftan-Kassim (1969); (11) Le Marne (1969); (12) Ribes (1969); (13) Terzian (1969); (14) Colla et al (1970); (15) Rubin (1970); (16) Thomasson & Davies (1970); (17) Higgs (1971); (18) Aller & Milne (1972); (19) Higgs (1973); (20) Terzian & Dickey (1973); (21) Sistla et al (1974); (22) Terzian et al (1974); (23) Milne & Aller (1975); (24) Telesco & Harper (1977); (25) Elias et al (1978); (26) Cohen & Barlow (1980); (27) Moseley (1980); (28) Ulich (1981); (29) Calabretta (1982)...…”

Section: Planck Dataunclassified

Planckintermediate results. XVIII. The millimetre and sub-millimetre emission from planetary nebulae

Arnaud¹,

Atrio-Barandela²,

Aumont³

et al. 2014

A&A

View full text Add to dashboard Cite

Late stages of stellar evolution are characterized by copious mass-loss events whose signature is the formation of circumstellar envelopes (CSE). Planck multi-frequency measurements have provided relevant information on a sample of Galactic planetary nebulae (PNe) in the important and relatively unexplored observational band between 30 and 857 GHz. Planck enables the assembly of comprehensive PNe spectral energy distributions (SEDs) from radio to far-IR frequencies. Modelling the derived SEDs provides us with information on physical properties of CSEs and the mass content of both main components: ionized gas, traced by the free-free emission at cm-mm waves; and thermal dust, traced by the millimetre and far-IR emission. In particular, the amount of ionized gas and dust has been derived here. Such quantities have also been estimated for the very young PN CRL 618, where the strong variability observed in its radio and millimetre emission has previously prevented constructing its SED. A morphological study of the Helix Nebula was also performed. Planck maps reveal, for the first time, the spatial distribution of the dust inside the envelope, allowing us to identify different components, the most interesting of which is a very extended component (up to 1 pc) that may be related to a region where the slow expanding envelope is interacting with the surrounding interstellar medium.

show abstract

A Survey of High-Frequency Radio Radiation from Planetary Nebulae

Cited by 7 publications

References 0 publications

Radio-continuum spectrum, brightness temperature, and planetary nebulae properties

Radio-continuum spectrum, brightness temperature, and planetary nebulae properties

The IUE Spectrum of the Binary Nucleus of the Planetary Nebula NGC 1514

Planckintermediate results. XVIII. The millimetre and sub-millimetre emission from planetary nebulae

Contact Info

Product

Resources

About