Formation of Bipolar Planetary Nebulae by Intermediate-Luminosity Optical Transients

Soker, Noam; Kashi, Amit

doi:10.1088/0004-637x/746/1/100

Cited by 71 publications

(97 citation statements)

References 65 publications

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“…This penetration would have occurred when the outer hourglass was smaller than it is now, which could explain for the large opening angle of each lobe (see Sahai & Trauger 1998). Soker & Kashi (2012) propose that the formation of bipolar lobes of some PNe and pre-PNe are the result of one or more intermediate-luminosity optical transient (ILOT) events. Jets created by the accretion of matter, from an AGB (or extreme-AGB) star, onto a main-sequence companion are launched by an accretion disk, which in turn shapes the bipolar lobes.…”

Section: Shaping Mechanisms and Offsetsmentioning

confidence: 99%

“…They support the O'Connor et al (2000) view that MyCn 18 was formed by a nova like explosion instead. However, in the light of the recent frequent discovery of hot Jupiter-type planets, it is possible to generate an ILOT event of significantly lower energy than envisaged by Soker & Kashi (2012). A planet engulfed at the AGB phase, surviving to spiral through the tenuous envelope to the dense core of the star and finally forming an accretion disk there (Nordhaus & Blackman 2006), gives a natural mechanism for breaking the spherical symmetry of the AGB phase.…”

Section: Shaping Mechanisms and Offsetsmentioning

confidence: 99%

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VLT observations of the asymmetric Etched Hourglass Nebula, MyCn 18

Clyne

Redman

Lloyd

et al. 2014

A&A

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Context. The mechanisms that form extreme bipolar planetary nebulae remain unclear. Aims. The physical properties, structure, and dynamics of the bipolar planetary nebula, MyCn 18, are investigated in detail with the aim of understanding the shaping mechanism and evolutionary history of this object. Methods. VLT infrared images, VLT ISAAC infrared spectra, and long-slit optical Echelle spectra are used to investigate MyCn 18. Morpho-kinematic modelling was used to firmly constrain the structure and kinematics of the source. A timescale analysis was used to determine the kinematical age of the nebula and its main components. Results. A spectroscopic study of MyCn 18's central and offset region reveals the detailed make-up of its nebular composition. Molecular hydrogen, atomic helium, and Bracket gamma emission are detected from the central regions of MyCn 18. ISAAC spectra from a slit position along the narrow waist of the nebula demonstrate that the ionised gas resides closer to the centre of the nebula than the molecular emission. A final reconstructed 3D model of MyCn 18 was generated, which provides kinematical information on the expansion velocity of its nebular components by means of position-velocity (P-V) arrays. A kinematical age of the nebula and its components were obtained by the P-V arrays and timescale analysis. Conclusions. The structure and kinematics of MyCn 18 are better understood using an interactive 3D modelling tool called SHAPE. A dimensional and timescale analysis of MyCn 18's major components provides a possible mechanism for the nebula's asymmetry. The putative central star is somewhat offset from the geometric centre of the nebula, which is thought to be the result of a binary system. We speculate that the engulfing and destruction of an exoplanet during the asymptotic giant branch phase may have been a key event in shaping MyCn 18 and generating of its hypersonic knotty outflow.

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Section: Shaping Mechanisms and Offsetsmentioning

confidence: 99%

Section: Shaping Mechanisms and Offsetsmentioning

confidence: 99%

VLT observations of the asymmetric Etched Hourglass Nebula, MyCn 18

Clyne

Redman

Lloyd

et al. 2014

A&A

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“…At the distance of 1.8 ± 0.3 kpc (Boumis & Meaburn 2013), the lobes extend over 7 pc in length, and it may be the product of an Intermediate Luminosity Optical Transient (ILOT) event, powered by a binary interaction (Soker & Kashi 2012). The small, low-excitation core is only ∼6 ′′ × 4 ′′ across, is nitrogen enriched (Vázquez et al 1998), and has an integrated flux, F (Hα) = 2.4 × 10 −13 erg cm −2 s −1 (López et al 2000).…”

Section: A1 Backgroundmentioning

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

166

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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“…Bond et al 2009;Kashi & Soker 2010b;Kasliwal et al 2011;Tylenda et al 2013). Several studies in recent years pointed to some connections between different ILOTS, e.g, between NGC 300OT and pre-planetary nebulae (PNe) ), between NGC 300OT and the Great Eruption of η Car, (Kashi et al 2010), and between NGC 300OT and the PN NGC 6302 and the pre-PNs OH231.8+4.2, M1-92 and IRAS 22036+5306 (Soker & Kashi 2012). Soker & Kashi (2012) proposed that the lobes of some (but not all) PNs and pre-PNs were formed in a several month-long ILOT event (or several close sub-events).…”

Section: Introductionmentioning

confidence: 99%

Forming equatorial rings around dying stars

Akashi

Sabach

Yogev

et al. 2015

Mon. Not. R. Astron. Soc.

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We suggest that clumpy-dense outflowing equatorial rings around evolved giant stars, such as in supernova 1987A and the Necklace planetary nebula, are formed by bipolar jets that compress gas toward the equatorial plane. The jets are launched from an accretion disk around a stellar companion. Using the FLASH hydrodynamics numerical code we perform 3D numerical simulations, and show that bipolar jets expanding into a dense spherical shell can compress gas toward the equatorial plane and lead to the formation of an expanding equatorial ring. RayleighTaylor instabilities in the interaction region break the ring to clumps. Under the assumption that the same ring-formation mechanism operates in massive stars and in planetary nebulae, we find this mechanism to be more promising for ring formation than mass loss through the second Lagrangian point. The jets account also for the presence of a bipolar nebula accompanying many of the rings.

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Formation of Bipolar Planetary Nebulae by Intermediate-Luminosity Optical Transients

Cited by 71 publications

References 65 publications

VLT observations of the asymmetric Etched Hourglass Nebula, MyCn 18

VLT observations of the asymmetric Etched Hourglass Nebula, MyCn 18

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

Forming equatorial rings around dying stars

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