6.14 Today´s new entry:
A case study in astronomical 3D printing: The mysterious Eta Carinae
Thomas I. Madura
Abstract: 3-D printing moves beyond interactive 3-D graphics and provides an excellent tool for both visual and tactile learners, since 3-D printing can now easily communicate complex geometries and full color information. Some limitations of interactive 3-D graphics are also alleviated by 3-D printable models, including issues of limited software support, portability, accessibility, and sustainability. We describe the motivations, methods, and results of our work on using 3-D printing (1) to visualize and understand the Eta Car Homunculus nebula and central binary system and (2) for astronomy outreach and education, specifically, with visually impaired students. One new result we present is the ability to 3-D print full-color models of Eta Car’s colliding stellar winds. We also demonstrate how 3-D printing has helped us communicate our improved understanding of the detailed structure of Eta Car’s Homunculus nebula and central binary colliding stellar winds, and their links to each other. Attached to this article are full-color 3-D printable files of both a red-blue Homunculus model and the Eta Car colliding stellar winds at orbital phase 1.045. 3-D printing could prove to be vital to how astronomer’s reach out and share their work with each other, the public, and new audiences.
Journal: Publications of the Astronomical Society of the Pacific Focus Issue “Techniques and Methods for Astrophysical Data Visualization”
Comments: Accepted November 15, 2016, 17 pages, 9 figures, 5 embedded interactive 3-D figures. 3-D print files are included as ancillary material in the /anc subfolder on the arxiv. Rep. Fig. 7 or 8.
URL of preprint: https://arxiv.org/abs/1611.09994
Submitted by: T. Madura
6.13 Today´s new entry:
Space reconstruction of the morphology and kinematics of axisymmetric radio sources
P.N. Diep, N.T. Phuong, D.T. Hoai, P.T. Nhung, N.T. Thao, P. Tuan-Anh, P. Darriulat
Abstract: The unprecedented quality of the observations available from the Atacama Large Millimetre/sub-millimetre Array (ALMA) calls for analysis methods making the best of them. Reconstructing in space the morphology and kinematics of radio sources is an underdetermined problem that requires imposing additional constraints for its solution. The hypothesis of rotational invariance about a well-defined star axis, which is a good approximation to the description of the gas envelopes of many evolved stars and protostars, is particularly efficient in this role. In the first part of the article, a systematic use of simulated observations allows for identifying the main problems and for constructing quantities aimed at solving them. In particular the evaluation of the orientation of the star axis in space and the differentiation between expansion along the star axis and rotation about it are given special attention. The use of polar rather than Cartesian sky coordinates is shown to better match the morphology and kinematics of actual stars. The radial dependence of the gas density and temperature and the possible presence of velocity gradients are briefly considered. In the second part, the results obtained in the first part are applied to a few stars taken as examples with the aim of evaluating their usefulness when applied to concrete cases. A third part takes stock of what precedes and formulates some guidelines for modelling the radio emission of axisymmetric radio sources, limited however to the mathematics and geometry of the problem, physics considerations being ignored.
Journal: Monthly Notices of the Royal Astronomical Society (MNRAS), 461, 4276–4294 (2016)
Submitted by: Pham Ngoc Diep