On the origin of planetary nebulae

Kwok, Sun; Purton, C. R.; Fitzgerald, Penelope

doi:10.1086/182621

Cited by 515 publications

(382 citation statements)

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“…During the protoplanetary nebula phase, the star rapidly (time scale Շ10 3 yr) evolves to the blue and creates a fast, v ϳ1000 km s Ϫ1 , wind. The fast wind drives a shell into the slow molecular wind at a speed of ϳ20-25 km s Ϫ1 (Kwok et al, 1978). The increasingly high-energy UV photons from the evolving star illuminate the circumstellar shell and carve out an ionized and atomic zone in the molecular gas (Pottasch, 1980).…”

Section: Pdrs In Different Radiation Fields a Planetary Nebulaementioning

confidence: 99%

Photodissociation regions in the interstellar medium of galaxies

Hollenbach

Tielens²

1999

Rev. Mod. Phys.

737

712

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The interstellar medium of galaxies is the reservoir out of which stars are born and into which stars inject newly created elements as they age. The physical properties of the interstellar medium are governed in part by the radiation emitted by these stars. Far-ultraviolet (6 eVϽh Ͻ13.6 eV) photons from massive stars dominate the heating and influence the chemistry of the neutral atomic gas and much of the molecular gas in galaxies. Predominantly neutral regions of the interstellar medium in which the heating and chemistry are regulated by far ultraviolet photons are termed PhotoDissociation Regions (PDRs). These regions are the origin of most of the non-stellar infrared (IR) and the millimeter and submillimeter CO emission from galaxies. The importance of PDRs has become increasingly apparent with advances in IR and submillimeter astronomy. The IR emission from PDRs includes fine structure lines of C, C ϩ , and O; rovibrational lines of H 2 ; rotational lines of CO; broad mid-IR features of polycyclic aromatic hydrocarbons; and a luminous underlying IR continuum from interstellar dust. The transition of H to H 2 and C ϩ to CO occurs within PDRs. Comparison of observations with theoretical models of PDRs enables one to determine the density and temperature structure, the elemental abundances, the level of ionization, and the radiation field. PDR models have been applied to interstellar clouds near massive stars, planetary nebulae, red giant outflows, photoevaporating planetary disks around newly formed stars, diffuse clouds, the neutral intercloud medium, and molecular clouds in the interstellar radiation field-in summary, much of the interstellar medium in galaxies. Theoretical PDR models explain the observed correlations of the [CII] 158 m with the CO Jϭ1 -0 emission, the CO Jϭ1 -0 luminosity with the interstellar molecular mass, and the [CII] 158 m plus [OI] 63 m luminosity with the IR continuum luminosity. On a more global scale, PDR models predict the existence of two stable neutral phases of the interstellar medium, elucidate the formation and destruction of star-forming molecular clouds, and suggest radiation-induced feedback mechanisms that may regulate star formation rates and the column density of gas through giant molecular clouds. [S0034-6861(99)01001-6] CONTENTS

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Section: Pdrs In Different Radiation Fields a Planetary Nebulaementioning

confidence: 99%

Photodissociation regions in the interstellar medium of galaxies

Hollenbach

Tielens²

1999

Rev. Mod. Phys.

737

712

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“…The very hot, ∼ 8 × 10 4 K, CS provides the energy to accelerate and ionize the gas forming a PN (Pottasch 1984;Bianchi, Cerrato, and Grewing 1986). This process has been quantified in the Interacting Stellar Winds Model in Kwok, Purton, and Fitzgerald (1978). Filipović et al (2009) reported the first confirmed extragalactic radio-continuum detection of 15 PNe in the Magellanic Clouds (MCs).…”

Section: Introductionmentioning

confidence: 99%

Radio planetary nebulae in the Small Magellanic Cloud

Leverenz¹,

Filipović²,

Bojičić³

et al. 2016

Astrophys Space Sci

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We present ten new radio continuum (RC) detections at catalogued planetary nebula (PN) positions in the Small Magellanic Cloud (SMC): SMP S6, LIN 41, LIN 142, SMP S13, SMP S14, SMP S16, J 18, SMP S18, SMP S19 and SMP S22. Additionally, six SMC radio PNe previously detected, LIN 45, SMP S11, SMP S17, LIN 321, LIN 339 and SMP S24 are also investigated (re-observed) here making up a population of 16 radio detections of catalogued PNe in the SMC. These 16 radio detections represent ∼15 % of the total catalogued PN population in the SMC. We show that six of these objects have characteristics that suggest that they are PN mimics: LIN 41, LIN 45, SMP S11, LIN 142, LIN 321 and LIN 339. We also present our

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“…Planetary nebulae are thought to be formed when a slow wind from the progenitor giant star is overtaken by a subsequent fast wind as the star enters its white dwarf stage 1 . The shock formed near the contact discontinuity between the two winds creates the relatively dense shell that forms the planetary nebula.…”

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confidence: 99%