The Toby Jug nebula (IC 2220): A bipolar and biconical nebula

Perkins, H. G.; King, David J.; Scarrott, S. M.

doi:10.1093/mnras/196.2.403

Cited by 4 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reimers (1977) estimated the total nebular mass to be on the order of > ∼ 1 M ⊙ from the extinction in the nebula. Perkins et al (1981) derived much smaller values of a few ×10 −2 M ⊙ from their polarization observations of the nebula. On the other hand, a detailed modeling of the aforementioned radio CO data suggests a total nebular mass of ∼1 M ⊙ (L.-Å.…”

Section: Parametermentioning

confidence: 98%

Infrared interferometric imaging of the compact dust disk around the AGB star HR3126 with the bipolar Toby Jug Nebula

Ohnaka

Schertl

Hofmann

et al. 2020

A&A

View full text Add to dashboard Cite

Aims. The asymptotic giant branch (AGB) star HR3126, associated with the arcminute-scale bipolar Toby Jug Nebula, provides a rare opportunity to study the emergence of bipolar structures at the end of the AGB phase. Our goal is to image the central region of HR3126 with high spatial resolution. Methods. We carried out long-baseline interferometric observations with AMBER and GRAVITY (2–2.45 μm) at the Very Large Telescope Interferometer with spectral resolutions of 1500 and 4500, speckle interferometric observations with VLT/NACO (2.24 μm), and imaging with SPHERE-ZIMPOL (0.55 μm) and VISIR (7.9–19.5 μm). Results. The images reconstructed in the continuum at 2.1–2.29 μm from the AMBER+GRAVITY data reveal the central star surrounded by an elliptical ring-like structure with a semimajor and semiminor axis of 5.3 and 3.5 mas, respectively. The ring is interpreted as the inner rim of an equatorial dust disk viewed from an inclination angle of ~50°, and its axis is approximately aligned with the arcminute-scale bipolar nebula. The disk is surprisingly compact, with an inner radius of a mere 3.5 R⋆ (2 au). Our 2-D radiative transfer modeling shows that an optically thick flared disk with silicate grains as large as ~4 μm can simultaneously reproduce the observed continuum images and the spectral energy distribution. The images reconstructed in the CO first overtone bands reveal elongated extended emission around the central star, suggesting the oblateness of the star’s atmosphere or the presence of a CO gas disk inside the dust cavity. The object is unresolved with SPHERE-ZIMPOL, NACO, and VISIR. Conclusions. If the disk formed together with the bipolar nebula, the grain growth from sub-micron to a few microns should have taken place over the nebula’s dynamical age of ~3900 yrs. The non-detection of a companion in the reconstructed images implies that either its 2.2 μm brightness is more than ~30 times lower than that of the red giant or it might have been shredded due to binary interaction.

show abstract

Section: Parametermentioning

confidence: 98%

Infrared interferometric imaging of the compact dust disk around the AGB star HR3126 with the bipolar Toby Jug Nebula

Ohnaka

Schertl

Hofmann

et al. 2020

A&A

View full text Add to dashboard Cite

show abstract

Polarized light from circumstellar dust: observations and models

Šolc

1989

Astron Nachr

View full text Add to dashboard Cite

Two models of a biconical dust nebula with an opaque torus in the symmetry plane are presented: a model containing dust in the whole biconical space ( A ) and an "empty" model with the dust layer on the surface of this empty space (B). Surface brightness distribution and polarization of the emitted light are computed using the Monte Carlo simulation of photon transport in the nebula. The results have features similar to those observed in several compact reflection nebulae. 1.IntroductionDense circumstellar dust clouds illuminated by a central star are of particular interest both for investigating their shape and for studying the solid grains of which they consist. The interpretation of the surface brightness measurements and polarimetric measurements may be strongly affected by the unknown geometry of such clouds. From the morphological point of view, the characteristic features of circumstellar envelopes projected on the celestial sphere may be divided into four classes: (i) circular or ring structure, (ii) flattened disk or torus, (iii) bipolar structure, (iv) combination of the above structures. While circular and elliptical structures are usually modelled by spherical shells and disks (hollow disks), bipolar structure can arise either due to an inclined ring or due to two lobes on opposite sides of the central star. In the present paper we make an attempt to approximate these lobes by a couple of conical segments centered on the star. Thus, only rotational symmetry is introduced into the model, and the inclination of the axis can be varied as one of the model parameters. 2.Radiative transfer treatmentFollowing previous models by VANYSEK and ~L C (1974) and WITT (1977a, b, c, d), we will describe the propagation of light through the nebula as a history of many individual photons moving within the nebula until they reach the surface and escape in the direction to the observer. Each photon trajectory originates in the central star which is represented as a point source with respect to the large dimensions of the envelope. The photon trajectory looks like a 3-D random walk, where the position of the scattering plane cp, the change of photon direction -the scattering angle 9 -, and the free path I between subsequent scattering are random quantities. In the following text the computed random values of these quantities will be denoted as "actual values". The probability densityf(9) of the scattering angle 9 is proportional to the intensity of the light scattered by the grain in a given direction (e.g., it is proportional to the sum of Mie's scattering functions i1(9) + i,(9) in case of spherical grains).The actual value of 9 can be computed fromwhere y is a random number with an uniform distribution in the interval ( 0 , l ) ; y is supplied by a random number generator. Each photon is associated with an orthogonal base of three unit vectors p, I, r. Vector p points to the photon direction.

show abstract

Recent Work on Bipolar Nebulae

Cohen¹

1983

Planetary Nebulae

View full text Add to dashboard Cite

The Toby Jug nebula (IC 2220): A bipolar and biconical nebula

Cited by 4 publications

References 0 publications

Infrared interferometric imaging of the compact dust disk around the AGB star HR3126 with the bipolar Toby Jug Nebula

Infrared interferometric imaging of the compact dust disk around the AGB star HR3126 with the bipolar Toby Jug Nebula

Polarized light from circumstellar dust: observations and models

Recent Work on Bipolar Nebulae

Contact Info

Product

Resources

About