3D Astrophysics Newsletter

2019_hsia10.7 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


3D Astrophysics Newsletter

2019_gomez10.6 Today´s new entry:

On the distance to expansion nebulae based on the improved distance mapping technique

Sebastián Gómez Gordillo

Abstract: Astrophysical objects as planetary nebulae (PNe), nova and supernova remnants and the stellar ejecta of luminous blue variables, among others, show radial expansion. An accurate distance determination is needed for all these kind of objects, since it is an essential parameter for deriving their physical characteristics, such as size, mass, luminosity and age. An innovative technique based on the expansion parallax method – the distance mapping technique, DMT – was recently proposed by Akras & Steffen (2012). It combines tangential velocity vectors from 3D morpho-kinematic models and observed proper motion vectors to estimate the distance. The DMT was improved and statistically studied in order to understand the relationship between its input parameters and the resulting distance. We successfully applied the DMT to four PNe (NGC 6702, NGC 6543, NGC 6302 and BD+30 3639), one nova remnant (Gk Persei) and the outer ejecta of η Carinae. New morpho-kinematic shape models are generated for NGC 6543, NGC 6302 and NGC 6702, whereas for the remaining nebulae published models are used. The new distance estimated for these objects is found to be in good agreement with previous studies, except for the complex multicomponent model of η Carinae. We demonstrated the DMT is an useful tool for revealing kinematically peculiar regions within the nebulae, in addition to provide robust distance determination.

Publication: Master Thesis, Universidade Federal do Rio de Janeiro, Observatorio de Valongo, Brazil
URL: http://objdig.ufrj.br/14/teses/865061.pdf
Submitted by: Sebastián Gómez

3D Astrophysics Newsletter

2019_scibelli10.5 Today´s new entry

High-velocity Bullets from V Hydrae, an Asymptotic Giant Branch Star in Transition: Ejection History and Spatio-kinematic Modeling

S. Scibelli, R. Sahai, M.R. Morris

The carbon star V Hydrae (V Hya) provides new insight into the nature of the launching mechanism of jet-like outflows that are believed to be the cause of the poorly understood transition phase of AGB stars into aspherical planetary nebulae. V Hya has been shown to periodically eject collimated gas blobs at high velocities (“bullets”). By analyzing data from HST/STIS 2-D spectra, obtained at six epochs spaced over a decade that show 4 successively ejected bullets with a spacing of 8.5 years, we have created kinematic models of the dynamical evolution of a specific bullet (#1) for the first three observed epochs (2002, 2003, 2004) using a 3D spatio-kinematic code, SHAPE. Using these models, we fit the observed morphology, line-of-sight velocity, proper motion and intensity for the extended, gaseous bullet as a function of time over a period of 2 years, in order to constrain its 3D movement and the evolution of its physical properties over this period. Our results suggest that although bullet #1’s motion is predominantly ballistic, there are small but significant changes in the position angle and inclination angle of the long (symmetry) axis of the bullet that tilt it progressively towards the symmetry axis of the bipolar molecular nebula around VHya. In contrast, bullet#3 shows strong acceleration soon after ejection. We discuss the possibilities that bullet acceleration is caused by either a non-radial magnetic field and/or by hydrodynamic interaction with the ambient gas through which the bullet is traveling.

Journal: The Astrophysical Journal, in press
URL of preprint: https://arxiv.org/pdf/1811.09277.pdf
Submitted by: S. Scibelli

3D Astrophysics Newsletter

2019_sabin3d10.4. Today´s new entry:

A Submillimeter Polarization Analysis of Frosty Leo

L. Sabin, Q. Zhang, R. Vázquez, W. Steffen

Abstract: We present a polarimetric investigation of the protoplanetary nebula Frosty Leo performed with the Submillimeter Array. We were able to detect, in the low continuum level (peak at 14.4 mJy/beam), a marginal polarization at ∼ 2.6σ. The molecular line investigation based on the CO J = 3 → 2 emission shows a peak emission of 68.1 Jy/beam km/s and the polarization detection in this CO line is also marginal, with a peak at ∼ 3.8σ. In both cases, it was therefore not possible to use the electric vector maps (E-field) to accurately trace the magnetic field (B-field) within the PPN.The spatio-kinematic modelling realised with the different velocity channel maps indicates three main structures: a distorted torus accompanied by a bipolar outflow or jet aligned with its axis and a flattened spherical “cap”. The comparison of the CO polarization segments with our model suggests that the polarized emission probably arises in the first two components.

Journal: Monthly Notices of the Royal Astronomical Society (MNRAS), in press
URL of preprint: https://arxiv.org/pdf/1901.06072.pdf
Submitted by: W. Steffen

3D Astrophysics Newsletter

2019_derlopa10.3 Today´s new entry:

High velocity string of knots in the outburst of the Planetary Nebula Hb4

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

Abstract: The bipolar collimated outflows of the Hb4 Planetary Nebula (PN) exhibit an evident decrease in their expansion velocity with respect to the distance from the central star. So far, similar velocity law has also been found in Herbig-Haro objects. The interpretation of this peculiar velocity law and the classification of the outflows is the main focal point of this paper. High dispersion long-slit echelle spectra along with high resolution images from Hubble Space Telescope (HST) are applied in the astronomical code SHAPE in order to reproduce a three-dimensional morpho-kinematical model for the core and the bipolar outflows. Its central part shows a number of low-ionization filamentary structures (knots and jets) indicative of common-envelope PNe evolution and it is reconstructed assuming a toroidal structure. The high-resolution HST [N II] image of Hb4 unveils the fragmented structure of outflows. The northern and southern outflows are composed by four and three knots, respectively, and each knot moves outwards with its own expansion velocity. They are reconstructed as string of knots rather than jets.This string of knots is formed by ejection events repeated every 200- 250 years. Hb4 displays several indirect evidence for a binary central system with a [WR] companion evolved through the common envelopes channel.The observed deceleration of the knots is likely associated with shock collisions between the knots and the interstellar medium or nebular material.

Journal: Monthly Notices of the Royal Astronomical Society (MNRAS), in press
URL of preprint: https://arxiv.org/pdf/1901.05767.pdf
Submitted by: W. Steffen

3D Astrophysics Newsletter

2019_ferrand10.2 Today´s new entry:

Engaging the Public with Supernova and Supernova Remnant Research Using Virtual Reality

Gilles Ferrand, Don Warren

Abstract: On 21 April 2018, the citizens of Wako, Japan, interacted in a novel way with research being carried out at the Astrophysical Big Bang Laboratory (ABBL) at RIKEN. They were able to explore a model of a supernova and its remnant in an immersive three-dimensional format by using virtual reality (VR) technology. In this article, we explain how this experience was developed and delivered to the public, providing practical tips for and reflecting on the successful organisation of an event of this kind.

Journal: Communicating Astronomy with the Public Journal
URL of preprint: https://arxiv.org/abs/1811.01542
Submitted by: Gilles Ferrand

3D Astrophysics Newsletter


Image Credit: NASA/CXC/MIT/T.DeLaney et al.

10.1 Today´s new entry:

Walking Through an Exploded Star: Rendering Supernova Remnant Cassiopeia A into Virtual Reality

Kimberly K. Arcand, Elaine Jiang, Sara Price, Megan Watzke, Tom Sgouros, Peter Edmonds

Abstract: NASA and other astrophysical data of the Cassiopeia A supernova remnant have been rendered into a three-dimensional virtual reality (VR) and augmented reality (AR) program, the first of its kind. This data-driven experience of a supernova remnant allows viewers to walk inside the leftovers from the explosion of a massive star, select the parts of the supernova remnant to engage with, and access descriptive texts on what the materials are. The basis of this program is a unique 3D model of the 340-year old remains of a stellar explosion, made by combining data from the NASA Chandra X-ray Observatory, Spitzer Space Telescope, and ground-based facilities. A collaboration between the Smithsonian Astrophysical Observatory and Brown University allowed the 3D astronomical data collected on Cassiopeia A to be featured in the VR/AR program, which is an innovation in digital technologies with public, education, and research-based impacts.

Journal: Communicating Astronomy with the Public Journal
URL of preprint: https://arxiv.org/abs/1812.06237
Submitted by: Sara Price