3D Astrophysics Newsletter

2020.6

Resolving Decades of Periodic Spirals from the Wolf–Rayet Dust Factory WR 112

Ryan M. Lau, Matthew J. Hankins, Yinuo Han, Izumi Endo, Anthony F. J. Moffat, Michael E. Ressler, Itsuki Sakon, Joel Sánchez-Bermúdez, Anthony Soulain, Ian R. Stevens, Peter G. Tuthill, Peredur M. Williams

Abstract: WR 112 is a dust-forming carbon-rich Wolf-Rayet (WC) binary with a dusty circumstellar nebula that exhibits a complex asymmetric morphology, which traces the orbital motion and dust formation in the colliding winds of the central binary. Unraveling the complicated circumstellar dust emission around WR 112 therefore provides an opportunity to understand the dust formation process in colliding-wind WC binaries. In this work, we present a multi-epoch analysis of the circumstellar dust around WR 112 using seven high spatial resolution (FWHM ∼0.3−0.4′′) N-band (λ∼12 μm) imaging observations spanning almost 20 years and includes newly obtained images from Subaru/COMICS in Oct 2019. In contrast to previous interpretations of a face-on spiral morphology, we observe clear evidence of proper motion of the circumstellar dust around WR 112 consistent with a nearly edge-on spiral with a θs=55∘ half-opening angle and a ∼20-yr period. The revised near edge-on geometry of WR 112 reconciles previous observations of highly variable non-thermal radio emission that was inconsistent with a face-on geometry. We estimate a revised distance to WR 112 of d=3.39+0.89−0.84 kpc based on the observed dust expansion rate and a spectroscopically derived WC terminal wind velocity of v∞=1230±260 km s−1. With the newly derived WR 112 parameters we fit optically-thin dust spectral energy distribution models and determine a dust production rate of M˙d=2.7+1.0−1.3×10−6 M⊙ yr−1, which demonstrates that WR 112 is one of the most prolific dust-making WC systems known.

Journal: The Astrophysical Journal, 900:190 (13pp), 2020 September 10
Submitted by: Ryan Lau

3D Astrophysics Newsletter

2020.5

Morphology and ionization characteristics of planetary nebulae PB 1 and PC 19

Bandyopadhyay, Rahul; Das, Ramkrishna; Mondal, Soumen; Ghosh, Samrat

Observation and 3-D mesh model of PC 19.

Abstract: We present results of our study of two planetary nebulae (PNe), PB1 and PC 19. We use the optical spectra of these two PNe observed at 2 m Himalayan Chandra Telescope and also archival and literature data for the study. We use the morphokinematic code shape to construct 3D morphologies of the PNe and the photoionization code cloudy to model the observed spectra. The 3D model of PB 1 consists of an elongated shell surrounded by a bipolar halo and that of PC 19 consists of an open lobed bipolar structure and a spiral filamentary pair. We analyse the ionization structure of the PNe by deriving several plasma parameters and by photoionization modelling. We estimate the elemental abundances of the elements, He, C, N, O, Ne, S, Ar, and Cl, from our analysis. We find He, C, and N abundances to be significantly higher in case of PB 1. We estimate different physical parameters of the central stars, namely effective temperature, luminosity, and gravity, and of the nebula, namely hydrogen density profiles, radii, etc., from photoionization modelling. We estimate distances to the PNe as ∼4.3 kpc for PB 1 and as ∼5.6 kpc for PC 19 by fitting the photoionization models to absolute observed fluxes. Progenitor masses are estimated from theoretical evolutionary trajectories and are found to be ∼1.67 and ∼2.38 M_☉ for PB 1 and PC 19, respectively.

Journal: Monthly Notices of the Royal Astronomical Society, Volume 496, Issue 1, pp.814-831
Submitted by: Rahul Bandyopadhyay

3D Astrophysics Newsletter

2020.4

First 3D Morpho-Kinematic model of Supernova Remnants. The case of VRO 42.05.01 (G 166.0+4.3)

S. Derlopa, P. Boumis, A. Chiotellis, W. Steffen, S. Akras

ABSTRACT
We present the first three dimensional (3D) Morpho-Kinematic (MK) model of a supernova
remnant (SNR), using as a case study the Galactic SNR VRO 42.05.01. We employed the
astrophysical code SHAPE in which wide field imaging and high resolution spectroscopic data were utilized, to reconstruct its 3D morphology and kinematics. We found that the remnant consists of three basic distinctive components that we call: a “shell”, a “wing” and a “hat”. With respect to their kinematic behaviour, we found that the “wing” and the “shell” have similar expansion velocities (Vexp = 115±5 km s⁻¹). The “hat” presents the lowest expansion velocity of the remnant (Vexp = 90±20 km s⁻¹), while the upper part of the “shell” presents the highest velocity with respect to the rest of the remnant (Vexp = 155±15 km s⁻¹). Furthermore, the whole nebula has an inclination of ∼3^◦-5^◦ with respect to the plane of the sky and a systemic velocity of Vsys = -17±3 km s⁻¹. We discuss the interpretation of our model results regarding the origin and evolution of the SNR and we suggest that VRO 42.05.01 had an interaction history with an inhomogeneous ambient medium most likely shaped by the mass outflows of its progenitor star.

Journal: Monthly Notices of the Royal Astronomical Society, 2020, in press
Preprint: https://arxiv.org/abs/2004.13498
Submitted by: W. Steffen

 

3D Astrophysics Newsletter

2020.3

Spectroscopic and geometrical evolution of the ejecta of the classical nova ASASSN-18fv

M. Pavana, A. Raj, T Bohlsen, G. C. Anupama, Ranjan Gupta, G. Selvakumar

Abstract: The optical spectroscopic observations of ASASSN-18fv observed from 2018 March 24 to 2019 Jan 26 are presented. The optical spectra are obtained from Mirranook, Vainu Bappu and South African Astronomical observatories. The spectra are dominated by hydrogen Balmer, Fe II and O I lines with P-Cygni profiles in the early phase, typical of an Fe II class nova. The spectra show He I lines along with H I and O I emission lines in the decline phase placing the nova in the hybrid class of novae. The spectra show rapid development in high ionization lines in this phase. Analysis of the light curve indicate t_2 and t_3 values of about 50 and 70 days respectively placing the nova in the category of moderately fast nova. The ejecta geometry, inclination and position angle are estimated using morpho-kinematic analysis. The geometry of the ejecta is found to be an asymmetric bipolar structure with an inclination angle of about 53∘. The ejected mass using photo-ionization analysis is found to be 6.07 × 10^(−4) M_⊙.

Journal: Monthly Notices of the Royal Astronomical Society, 2020, 495, 2, pp 2075–2087
Preprint: https://arxiv.org/abs/2004.13498
Submitted by: M. Pavana

3D Astrophysics Newsletter

2020.2

PyCross 3D Photoionization Model

Introducing PyCross: PyCloudy Rendering Of Shape Software for pseudo 3D ionisation modelling of nebulae

K.Fitzgerald, E.J.Harvey, N.Keaveney, M.P.Redman

Abstract: Research into the processes of photoionised nebulae plays a significant part in our understanding of stellar evolution. It is extremely difficult to visually represent or model ionised nebula, requiring astronomers to employ sophisticated modelling code to derive temperature, density and chemical composition. Existing codes are available that often require steep learning curves and produce models derived from mathematical functions. In this article we will introduce PyCross: PyCloudy Rendering Of Shape Software. This is a pseudo 3D modelling application that generates photoionisation models of optically thin nebulae, created using the Shape software. Currently PyCross has been used for novae and planetary nebulae, and it can be extended to Active Galactic Nuclei or any other type of photoionised axisymmetric nebulae. Functionality, an operational overview, and a scientific pipeline will be described with scenarios where PyCross has been adopted for novae (V5668 Sagittarii (2015) & V4362 Sagittarii (1994)) and a planetary nebula (LoTr1). Unlike the aforementioned photoionised codes this application neither requires any coding experience, nor the need to derive complex mathematical models, instead utilising the select features from Cloudy  / PyCloudy and Shape. The software was developed using a formal software development lifecycle, written in Python and will work without the need to install any development environments or additional python packages. This application, Shape models and PyCross archive examples are freely available to students, academics and research community on GitHub for download.

Journal: Astronomy and Computing, Volume 32, July 2020, 100382
Preprint: https://arxiv.org/abs/2005.02749
Submitted by: K. Fitzgerald

3D Astrophysics Newsletter

2020.01

E0102-VR: exploring the scientific potential of Virtual Reality for observational astrophysics

Enrico Baracaglia, Frédéric P.A. Vogt

Abstract: Virtual Reality (VR) technology has been subject to a rapid democratization in recent years, driven in large by the entertainment industry, and epitomized by the emergence of consumer-grade, plug-and-play, room-scale VR devices. To explore the scientific potential of this technology for the field of observational astrophysics, we have created an experimental VR application: E0102-VR. The specific scientific goal of this application is to facilitate the characterization of the 3D structure of the oxygen-rich ejecta in the young supernova remnant 1E 0102.2-7219 in the Small Magellanic Cloud. Using E0102-VR, we measure the physical size of two large cavities in the system, including a (7.0±0.5) pc-long funnel structure on the far-side of the remnant. The E0102-VR application, albeit experimental, demonstrates the benefits of using human depth perception for a rapid and accurate characterization of complex 3D structures. Given the implementation costs (time-wise) of a dedicated VR application like E0102-VR, we conclude that the future of VR for scientific purposes in astrophysics most likely resides in the development of a robust, generic application dedicated to the exploration and visualization of 3D observational datasets, akin to a “ds9-VR”.

Journal: Astronomy & Computing 30 (2020) 100352
Preprint: https://arxiv.org/pdf/1911.04500.pdf
Submitted by: Frédéric P.A. Vogt

3D Astrophysics Newsletter

10.10 Today´s new entry:

Evolution from Spherical AGB Wind to Multipolar Outflow in Pre-Planetary Nebula IRAS 17150-3224

Po-Sheng Huang, Chin-Fei Lee, Raghvendra Sahai

We have mapped the pre-planetary nebula IRAS 17150-3224 in 350 GHz continuum and CO J=3-2 line at an angular resolution of about 0″.09 using the Atacama Large Millimeter/submillimeter Array. A continuum source is detected at the center of the nebula, elongated along the equatorial plane, likely tracing a dusty torus around the central source. Continuum emission is also detected on both sides of the central continuum source in the equatorial plane, probably resulting from interactions of collimated fast winds with envelope material in the equator. CO emission is detected along the optical lobe. Although the optical lobe appears as bipolar, CO map shows that it is actually a quadrupolar outflow consisting of two overlapping bipolar outflows. Two additional younger bipolar outflows are also detected in CO, one at lower latitude and the other along the equatorial plane. In the CO position-velocity maps, blueshifted absorption stripes are detected in the outflow emissions, due to absorption by a series of shells produced by a series of asymptotic giant branch (AGB) wind ejections. By modeling the morphology and kinematics of the AGB wind and outflows, we find that the AGB wind could end about 1300 yr ago, the quadrupolar outflow was ejected about 350 yr ago, and the two additional bipolar outflows were ejected about 280 and 200 ago, respectively. The outflows could be produced either by bullets coming from an explosion, or by a precessing collimated fast wind with a time-dependent ejection velocity.

Journal: The Astrophysical Journal in press
Preprint: arXiv:1912.06358
Submitted by: Po-Sheng Huang

3D Astrophysics Newsletter

10.9 Today´s new entry:

Spatio-kinematical model of the collimated molecular outflow in the water-fountain nebula IRAS 16342−3814

D. Tafoya, G. Orosz, W. H. T. Vlemmings, R. Sahai, and A. F. Pérez-Sánchez

Context. Water fountain nebulae are AGB and post-AGB objects that exhibit high-velocity outflows traced by water maser emission. Their study is important to understand the interaction between collimated jets and the circumstellar material that leads to the formation of bipolar/multi-polar morphologies in evolved stars.
Aims. To describe the three-dimensional morphology and kinematics of the molecular gas of the water-fountain nebula IRAS 16342−3814.
Methods. Retrieving data from the ALMA archive to analyse it using a simple spatio-kinematical model. Using the software SHAPE to construct a three-dimensional spatio-kinematical model of the molecular gas in IRAS 16342−3814. Reproducing the intensity
distribution and position-velocity diagram of the CO emission from the ALMA observations to derive the morphology and velocity field of the gas. Using CO(J=1→0) data to support the physical interpretation of the model.
Results. A spatio-kinematical model that includes a high-velocity collimated outflow embedded within material expanding at relatively lower velocity reproduces the images and position-velocity diagrams from the observations. The derived morphology is in good agreement with previous results from IR and H2O maser emission observations. The high-velocity collimated outflow exhibits deceleration across its length, while the velocity of the surrounding component increases with distance. The morphology of the emitting region; the velocity field and the mass of the gas as function of velocity are in excellent agreement with the properties predicted for a molecular outflow driven by a jet. The timescale of the molecular outflow is estimated to be ∼70-100 years. The scalar momentum carried by the outflow is much larger than it can be provided by the radiation of the central star. An oscillating pattern was found associated to the high-velocity collimated outflow. The oscillation period of the pattern is T≈60-90 years and its opening angle is θop≈2◦.
Conclusions. The CO (J=3→2) emission in IRAS 16342−3814 is interpreted in terms of a jet-driven molecular outflow expanding along an elongated region. The position-velocity diagram and the mass spectrum reveal a feature due to entrained material that is associated to the driving jet. This feature is not seen in other more evolved objects that exhibit more developed bipolar morphologies. It is likely that the jet in those objects has already disappeared since it is expected to last only for a couple of hundred years. This
strengthens the idea that water fountain nebulae are undergoing a very short transition during which they develop the collimated outflows that shape the CSE. The oscillating pattern seen in the CO high-velocity outflow is interpreted as due to precession with a
relatively small opening angle. The precession period is compatible with the period of the corkscrew pattern seen at IR wavelengths. We propose that the high-velocity molecular outflow traces the underlying primary jet that produces such pattern.

Journal: Astronomy & Astrophysics, 629, A8, pp. 10
Preprint: https://arxiv.org/pdf/1906.06328.pdf
Submitted by: Daniel Tafoya

3D Astrophysics Newsletter

10.8 Today´s new entry:

Touching the stars: improving NASA 3D printed data sets with blind and visually impaired audiences

Kimberly K. Arcand, April Jubett, Megan Watzke, Sara Price, Kelly T.S. Williamson, Peter Edmonds

Astronomy has been an inherently visual area of science for millenia, yet a
majority of its significant discoveries take place in wavelengths beyond
human vision. There are many people, including those with low or no
vision, who cannot participate fully in such discoveries if visual media is the
primary communication mechanism. Numerous efforts have worked to
address equity of accessibility to such knowledge sharing, such as through
the creation of three-dimensional (3D) printed data sets. This paper
describes progress made through technological and programmatic
developments in tactile 3D models using NASA’s Chandra X-ray
Observatory to improve access to data.

Journal: Journal of Science Communication
Preprint: https://arxiv.org/abs/1906.06457
Submitted by: Sara Price

 

3D Astrophysics Newsletter

10.7 Today´s new entry

A Young Multipolar Planetary Nebula in the Making – IRAS 21282+5050

Chih-Hao Hsia, Yong Zhang, Sun Kwok, Wayne Chau

Abstract: We present high-angular-resolution Hubble Space Telescope (HST) optical and near-infrared imaging of the compact planetary nebula (PN) IRAS 21282+5050. Optical images of this object reveal several complex morphological structures including three pairs of bipolar lobes and an elliptical shell lying close to the plane of the sky. From near-infrared observations, we found a dust torus oriented nearly perpendicular to the major axis of elliptical shell. The results suggest that IRAS 21282+5050 is a multipolar PN, and these structures developed early during the post asymptotic-giant-branch (AGB) evolution. From a three-dimensional (3-D) model, we derived the physical dimensions of these apparent structures. When the 3-D model is viewed from different orientations, IRAS 21282+5050 shows similar apparent structures as other multipolar PNs. Analysis of the spectral energy distribution and optical spectroscopic observations of the nebula suggests the presence of a cool companion to the hot central star responsible for the ionization of the nebula. Whether the binary nature of the central star has any relations with the multipolar structure of the nebula needs to be further investigated.

Journal: Astrophysics and Space Science, 2019, 364:32
Preprint: https://arxiv.org/pdf/1902.08851.pdf
Submitted by: Sun Kwok