Astronomers can now hold stellar nurseries in their hands

With 3D printing, researchers can now hold great nurseries in their hands and uncover features that are often obscured in traditional renderings and animations.

Astronomers can’t touch the stars they are studying, but astrophysicist Nia Imara uses three-dimensional models that fit in the palm of your hand to decipher the structural complexities of star nurseries, the huge clouds of gas and dust in which star formation occurs.

Imara and her team created the models with data from simulations of star formation clouds and a sophisticated 3D printing process in which the fine-scale densities and gradients of the turbulent clouds are embedded in a transparent resin. The resulting models – the first 3D-printed star kindergartens – are highly polished spheres the size of a baseball (8 centimeters in diameter) in which the star-forming material appears as swirling lumps and threads.

“We wanted an interactive object that helps us visualize the structures in which stars are formed so that we can better understand the physical processes,” said Imara, assistant professor of astronomy and astrophysics at UC Santa Cruz and first author of an article that this novel approach is described on August 25, 2021, in Astrophysical magazine covers.

In addition to spheres representing nine different simulations, the researchers also printed hemispheres to reveal the midplane data. Lighter material corresponds to areas of higher density, while darker areas represent areas of low density and voids. Image Credit: Photo by Saurabh Mhatre

As an artist and astrophysicist, Imara said the idea was an example of science’s imitation of art. “Years ago I drew a portrait of myself touching a star. Later the idea just clicked. Molecular cloud star formation is my specialty, so why not try and make one? ”She said.

She worked with co-author John Forbes at the Center for Computational Astrophysics at the Flatiron Institute to develop a series of nine simulations depicting various physical conditions in molecular clouds. The collaboration also included co-author James Weaver from the School of Engineering and Applied Sciences at Harvard University, who helped transform the data from the astronomical simulations into physical objects using high-resolution and photo-realistic multi-material 3D printing.

The results are both visually striking and scientifically revealing. “Aesthetically, they are really amazing to look at, and then you start to notice the complex structures that are incredibly difficult to see with the usual techniques used to visualize these simulations,” said Forbes.

For example, plate-shaped or pancake-shaped structures are difficult to distinguish in two-dimensional sections or projections because a section through a plate looks like a filament.

Nia Imara is an astrophysicist and artist at the same time. Photo credit: Courtesy of Nia Imara

“You can clearly see a two-dimensional leaf inside the spheres and there are tiny filaments in there, and that’s amazing from the perspective of a person trying to understand what’s going on in these simulations,” said Forbes.

The models also show structures that are more continuous than they would appear in 2D projections, Imara said. “When you have something winding through space, you may not realize that two regions are connected by the same structure. So when we have an interactive object that you can rotate, we can see those continuities more easily, ”she said.

Nia Imara is an astrophysicist and artist at the same time. A portrait of yourself touching a star eventually led to the idea of ​​creating physical models of star kindergartens. Image Credit: Image courtesy of Nia Imara

The nine simulations on which the models are based were designed to study the effects of three fundamental physical processes that determine the evolution of molecular clouds: turbulence, gravity and magnetic fields. By changing various variables, such as the strength of the magnetic fields or the speed of the gas, the simulations show how different physical environments affect the morphology of substructures in connection with star formation.

Stars tend to form in clumps and cores located at the intersection of filaments, where the density of gas and dust becomes high enough for gravity to take control. “We believe that the rotations of these newborn stars depend on the structures in which they form – stars in the same filament will ‘know’ each other’s rotations,” said Imara.

The physical models don’t need an astrophysicist with experience in these processes to see the differences between the simulations. “When I looked at 2D projections of the simulation data, it was often difficult to see the subtle differences, while it was obvious with the 3D-printed models,” said Weaver, who has a background in biology and materials science and routinely uses 3D- Pressure used to study the structural details of a wide variety of biological and synthetic materials.

“I’m very interested in the interface between science, art and education and I use 3D printing as a tool to make complex structures and processes easy to understand,” says Weaver. “Traditional extrusion-based 3D printing can only produce solid objects with a continuous outer surface, and that’s problematic when trying to represent gases, clouds, or other diffuse shapes. Our approach uses an inkjet-like 3D printing process to deposit tiny individual droplets of opaque resin in precise locations within a surrounding volume of transparent resin in order to define the shape of the cloud in minute detail. “

He pointed out that in the future, by using different colors, the models could also incorporate additional information to increase their scientific value. Researchers are also interested in exploring the use of 3D printing to represent observational data from nearby molecular clouds such as those in the constellation Orion.

The models can also serve as valuable tools for education and outreach, said Imara, who plans to use them in an astrophysics class she will be teaching this fall.

Reference: “Touching the Stars: Using High-Resolution 3D Printing to Visualize Stellar Nurseries” by Nia Imara, John C. Forbes and James C. Weaver, August 25, 2021, Astrophysical magazine covers.
DOI: 10.3847 / 2041-8213 / ac194e