A study of some southern planetary nebulae

Meatheringham, S. J.; Wood, P. R.; Faulkner, D. J.

doi:10.1086/166882

Cited by 60 publications

(87 citation statements)

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“…The heliocentric systemic velocity, V sys , is −70.56 km s −1 calculated using slit g, which passes through the central star. This velocity is in good agreement with the velocity derived by Corradi et al (2000) and Meatheringham et al (1988).…”

Section: Discussionsupporting

confidence: 90%

The Outflows and Three-Dimensional Structure of NGC 6337: A Planetary Nebula With a Close Binary Nucleus

García-Díaz¹,

Clark²,

López³

et al. 2009

ApJ

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NGC 6337 is a member of the rare group of planetary nebulae where a close binary nucleus has been identified. The nebula's morphology and emission line profiles are both unusual, particularly the latter. We present a thorough mapping of spatially resolved, long-slit echelle spectra obtained over the nebula that allows a detailed characterization of its complex kinematics. This information, together with narrowband imagery, is used to produce a three-dimensional (3D) model of the nebula using the code SHAPE. The 3D model yields a slowly expanding toroid with large density fluctuations in its periphery that are observed as cometary knots. A system of bipolar expanding caps of low ionization is located outside the toroid. In addition, an extended high velocity and tenuous bipolar collimated outflow is found emerging from the core and sharply bending in opposite directions, a behavior that cannot be accounted for by pure magnetic launching and collimation unless the source of the outflow is precessing or rotating, as could be expected from a close binary nucleus.

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Section: Discussionsupporting

confidence: 90%

The Outflows and Three-Dimensional Structure of NGC 6337: A Planetary Nebula With a Close Binary Nucleus

García-Díaz¹,

Clark²,

López³

et al. 2009

ApJ

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“…Dufour (1984) and Pedreros (1989) also assumed a physical association, but gave conflicting distances to the cluster. However, Mermilliod et al (2001) obtained accurate velocities for 12 cluster red giants to obtain a mean velocity of V hel = +20.7 ± 0.3 kms −1 , significantly different to the PN velocity of −1 ± 3 kms −1 (Meatheringham et al 1988), suggesting a line-ofsight coincidence. More recently, Vázquez (2012) reanalysed the complex kinematics of the nebula, finding a systemic heliocentric velocity (∼27 kms −1 ) in closer agreement with the open cluster, suggesting membership, with which we now concur.…”

Section: Cluster Distancesmentioning

confidence: 86%

“…Variations on this technique, by assuming an ionised mass derived from a set of calibration objects at known distance and using the observable electron density and Hβ flux to infer a distance, have been utilised by Kingsburgh & Barlow (1992) and Kingsburgh & English (1992). A more novel method has been utilised by Meatheringham, Wood & Faulkner (1988), who found that Magellanic Cloud (MC) PNe fall on fairly tight plane in dynamical age -density -excitation-class space. For a sample of Galactic PNe the dynamical age was estimated from the observed electron density and excitation class, and once the expansion velocity is measured, the intrinsic radius can be inferred.…”

Section: Previous Statistical Methodsmentioning

confidence: 99%

The H surface brightness-radius relation: a robust statistical distance indicator for planetary nebulae

Frew¹,

Parker²,

Bojičić³

2015

Monthly Notices of the Royal Astronomical Society

173

127

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Measuring the distances to Galactic planetary nebulae (PNe) has been an intractable problem for many decades. We have now established a robust optical statistical distance indicator, the Hα surface brightness -radius or S Hα -r relation, which addresses this problem. We developed this relation from a critically evaluated sample of primary calibrating PNe. The robust nature of the method results from our revised calibrating distances with significantly reduced systematic uncertainties, and the recent availability of high-quality data, including updated nebular diameters and integrated Hα fluxes. The S Hα -r technique is simple in its application, requiring only an angular size, an integrated Hα flux, and the reddening to the PN. From these quantities, an intrinsic radius is calculated, which when combined with the angular size, yields the distance directly. Furthermore, we have found that optically thick PNe tend to populate the upper bound of the trend, while optically-thin PNe fall along the lower boundary in the S Hα -r plane. This enables sub-trends to be developed which offer even better precision in the determination of distances, as good as 18 per cent in the case of optically-thin, high-excitation PNe. This is significantly better than any previous statistical indicator. We use this technique to create a catalogue of statistical distances for over 1100 Galactic PNe, the largest such compilation in the literature to date. Finally, in an appendix, we investigate both a set of transitional PNe and a range of PN mimics in the S Hα -r plane, to demonstrate its use as a diagnostic tool. Interestingly, stellar ejecta around massive stars plot on a tight locus in S Hα -r space with the potential to act as a separate distance indicator for these objects.

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“…The torus of NGC 6778 is notable for its high expansion velocity of 2V exp = 60-70 km s −1 (Maestro et al 2004), while Meatheringham et al (1988) found a slower 2V exp = 30 ± 3 km s −1 for NGC 6326. It is interesting to note that other post-CE nebulae show similarly high expansion speeds as NGC 6778 including ETHOS 1 (2V exp = 110 km s −1 , Miszalski et al 2011b), A 41 (2V exp = 80 km s −1 , Jones et al 2010) and the Necklace (2V exp = 56 km s −1 , Corradi et al 2011).…”

Section: General Propertiesmentioning

confidence: 99%

Discovery of close binary central stars in the planetary nebulae NGC 6326 and NGC 6778

Miszalski

Jones

Rodríguez‐Gil

et al. 2011

A&A

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We present observations proving the close binary nature of the central stars belonging to the planetary nebulae (PNe) NGC 6326 and NGC 6778. Photometric monitoring reveals irradiated lightcurves with orbital periods of 0.372 and 0.1534 days, respectively, constituting firm evidence that they passed through a common-envelope (CE) phase. Unlike most surveys for close binary central stars (CSPN) however, the binary nature of NGC 6326 was first revealed spectroscopically and only later did photometry obtain an orbital period. Gemini South observations revealed a large 160 km s −1 shift between the nebula and emission lines of C III and N III well known to originate from irradiated atmospheres of main-sequence companions. These so-called weak emission lines are fairly common in PNe and measurement of their radial velocity shifts in spectroscopic surveys could facilitate the construction of a statistically significant sample of post-CE nebulae. There is growing evidence that this process can be further accelerated by preselecting nebulae with traits of known post-CE nebulae. Both NGC 6326 and NGC 6778 were selected for their rich attribution of low-ionisation filaments and collimated outflows, thereby strengthening the connection between these traits and post-CE CSPN.

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A study of some southern planetary nebulae

Cited by 60 publications

References 0 publications

The Outflows and Three-Dimensional Structure of NGC 6337: A Planetary Nebula With a Close Binary Nucleus

The Outflows and Three-Dimensional Structure of NGC 6337: A Planetary Nebula With a Close Binary Nucleus

The H surface brightness-radius relation: a robust statistical distance indicator for planetary nebulae

Discovery of close binary central stars in the planetary nebulae NGC 6326 and NGC 6778

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