3D Astrophysics Newsletter

Shaded 3D model of the planetary nebula NGC 3242. For the volume rendering and comparison with observations, please check out the paper by Gómez-Muñoz et al.

Shaded 3D model of the planetary nebula NGC 3242. For the volume rendering and comparison with observations, please check out the paper by Gómez-Muñoz et al.

4.3 Today´s new entry:

Morpho-kinematics of the planetary nebula NGC 3242: an analysis beyond its multiple-shell structure

M. A. Gómez-Muñoz, M. W. Blanco Cárdenas, R. Vázquez, S. Zavala, P. F. Guillén, S. Ayala

Abstract: In this paper we present the results of optical high-resolution imaging and spectroscopy of the complex planetary nebula (PN) NGC 3242. Our study is based on the analysis of the narrowband Hα λ6563\AA , [O III] λ5007\AA , [N II] λ6584\AA , and [S II] λ6724{\AA} images, and high- resolution spectroscopy using spectral ranges centered on the Hα λ6564\AA , [N II] λ6583\AA , and [O III] λ5007\AA . We detected and analysed morphological components beyond the multiple shell structure of this PN, to investigate the small-scale morphological components aligned towards its major axis (such as knots and ansae, as well as the arc-like features) and its surroundings. Thus, we investigated the morpho-kinematical properties of NGC 3242, as well as their nature and formation. Our results regarding the elliptical double-shell structure and the distance to this nebula are in concordance with previous studies. Furthermore, we have used the software SHAPE to construct a 3D model of NGC 3242, allowing us to successfully reproduce our observational data. We conclude that the prominent knots emitting in the [N II] line are fast, low-ionisation emission regions (FLIERs) related to high velocity jets and the so-called ansae-like features rather resemble bubbles. The disruptions immersed in the halo, whose emission was detected in the the [O III] high-excitation emission line, remarkably display high velocities and were formed likely in an earlier ejection event, in comparison to the innermost FLIERs and bubbles. Finally, according to our model, the kinematical ages of the structures in NGC 3242 range from 390 to 5400 yr.

Journal: Monthly Notices of the Royal Astronomical Society, in press
Comments: 10 pages, 12 figures, 3 tables
URL of preprint: http://arxiv.org/abs/1508.05115
Submitted by: Marco A. Gómez-Muñoz

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3-D rendering and scientific insight

A hydrodynamic simulation of the dust in the Homunculus Nebula around Eta Carinae rendered for different wavelength ranges from the optical to far infrared.

A hydrodynamic simulation and rendering of the light scattering and emission from dust in the Homunculus Nebula around Eta Carinae for different wavelength ranges (optical to far infrared). The simulation and rendering was done in the SHAPE software (W. Steffen, UNAM).

How do you like your 3D model to be rendered? Do you prefer isosurfaces or realistic radiation transfer or maybe volumetric but with custom colors? Even 3D-printed in plastic? Any particular color? Maybe you still fancy good old contour plots. What are you after? The how-cool-effect or scientific insight? Right, both…of course. Sounds like choosing from a long restaurant menu…and is almost as hard to decide. Continue reading

3D Astrophysics Newsletter

Top: The Itokawa shape model that was used to generate simulated radar images (Ostro et al. 2005).Bottom: The best-fit SRIF model for those simulated data

Top: The Itokawa shape model that was used to generate simulated radar images (Ostro et al. 2005). Bottom: The best-fit SRIF model for those simulated data

4.2 Today´s new entry:

Improved Algorithms for Radar-Based Reconstruction of Asteroid Shapes

Adam H. Greenberg, Jean-Luc Margot

Abstract: We describe our implementation of a global-parameter optimizer and Square Root Information Filter (SRIF) into the asteroid-modelling software shape. We compare the performance of our new optimizer with that of the existing sequential optimizer when operating on various forms of simulated data and actual asteroid radar data. In all cases, the new implementation performs substantially better than its predecessor: it converges faster, produces shape models that are more accurate, and solves for spin axis orientations more reliably. We discuss potential future changes to improve shape’s fitting speed and accuracy.

Journal: The Astronomical Journal
Comments: Accepted 2015-Jul-29, 12 pages, 9 figures
URL of preprint: http://arxiv.org/pdf/1508.00563.pdf
Submitted by: Adam H. Greenberg