3D printing meets computational astrophysics: deciphering the structure of η Carinae's inner colliding winds

Abstract

We present the first 3D prints of output from a supercomputer simulation of a complex astrophysical system, the colliding stellar winds in the massive ( 120 M ), highly eccentric (e ∼ 0.9) binary star system η Carinae. We demonstrate the methodology used to incorporate 3D interactive figures into a PDF journal publication and the benefits of using 3D visualization and 3D printing as tools to analyze data from multidimensional numerical simulations. Using a consumer-grade 3D printer (MakerBot Replicator 2X), we successfully printed 3D smoothed particle hydrodynamics (SPH) simulations of η Carinae's inner (r ∼ 110 au) windwind collision interface at multiple orbital phases. The 3D prints and visualizations reveal important, previously unknown 'finger-like' structures at orbital phases shortly after periastron (φ ∼ 1.045) that protrude radially outward from the spiral wind-wind collision region. We speculate that these fingers are related to instabilities (e.g. thin-shell, Rayleigh-Taylor) that arise at the interface between the radiatively-cooled layer of dense post-shock primarystar wind and the fast (3000 km s −1 ), adiabatic post-shock companion-star wind. The success of our work and easy identification of previously unrecognized physical features highlight the important role 3D printing and interactive graphics can play in the visualization and understanding of complex 3D time-dependent numerical simulations of astrophysical phenomena.

Tov∞and beyond! The He i absorption variability across the 2014.6 periastron passage of η Carinae

“…• We qualitatively compared the observations to 3D SPH simulations of the system (e.g., Madura et al 2013Madura et al , 2015 and find that the secondary absorption variability can be well explained if we look across the edge of the shock cone near periastron. This geometry is dependent on the inclination of the system and the ratio of the mass-loss rates between η Car A and η Car B , and there is a degeneracy between these parameters.…”

“…13 shows that as the system gets very close to periastron, the WWC region becomes highly distorted in the direction of orbital motion and the secondary star begins to become deeply embedded within the dense wind of the primary. As discussed in Madura et al (2013Madura et al ( , 2015, around this phase and leading into periastron, the receding secondary wind is unable to collide with the receding primary wind, leading to the lack of an extended hot (> 10 6 K) trailing arm to the WWC zone. The models indicate that the post-shock secondary wind located near the apex of the WWC zone also has switched to the radiative regime at this time and is now much cooler (T 10 4 K).…”

“…In the absence of significant orbital motion, the WWC zone has a simple paraboloidal shape that curves towards the star with the weaker wind (Canto et al 1996). In highly elliptical systems like η Car, as the stars approach periastron, orbital speeds increase approaching the primary wind speed, highly distorting the WWC region, giving it a distinct spiral shape after periastron (Okazaki et al 2008;Parkin et al 2011;Madura et al , 2013Madura et al , 2015. Orbital motion also alters our viewing angle to different portions of the WWC zone, and hence the strength and radial velocity of observed emission and absorption lines (Damineli et al 2008).…”

“…Three-dimensional (3D) hydrodynamical and radiative transfer simulations of η Car's binary colliding winds have provided crucial insights on the time-dependent geometry and ionization state of the WWCs, helping constrain the binary orientation, wind parameters, and locations where various observed emission and absorption features arise (Okazaki et al 2008;Parkin et al 2009Parkin et al , 2011Groh et al 2012a,b;Madura et al , 2013Madura et al , 2015Clementel et al 2014Clementel et al , 2015a. Using a 3D dynamical model of the broad, extended [Fe III] emission observed in η Car by the HST/STIS (Gull et al 2009), confirmed the orbital inclination and argument of periapsis derived by Okazaki et al (2008) and Parkin et al (2009) using X-ray data.…”

AstroBlend: An astrophysical visualization package for Blender

“…Recent innovations in the computer graphics and gaming industry can be exploited for this multi-pronged approach to data investigation [5,11]. In addition to increasing the rate of information exchange within scientific collaborations, as technological advancements in graphics and gaming progress, innovative methods for discussing scientific concepts with the general public can be developed [12,13,14,15,16].…”