Citizen scientists detect dusty discs – Sky & Telescope

The wealth of data generated by current missions can overwhelm professional astronomers, so over the past decade research groups have increasingly relied on citizen scientists. Disk Detectives is a project that appeals to the watchful eye and enthusiasm of the general public. Here, citizen scientists explore planet-forming sites around stars, leading to the findings reported at the American Astronomical Society’s 240th meeting in Pasadena, California.

Future exoplanets

Planets form in protoplanetary discs, Frisbee-like structures of gas and dust swirling around fledgling stars; once the evolving stars push out the gas, debris discs dust and small bodies remain. (We have our own debris disk, the Kuiper Belt, and we see the dust left over from the formation of our solar system in the form of zodiacal light.)

This Atacama Large Millimeter/submillimeter Array from the European Southern Observatory shows the protoplanetary disk surrounding the young star HL Tauri. The gaps revealed by these observations show the possible positions of the forming planets in the system.

NASA’s Wide-Field Infrared Survey Explorer (WISE) has led to the discovery of tens of thousands of disc candidates among 2 billion objects awaiting classification. But how does a research group with limited time and resources sift through tons of data looking for suitable candidates?

Enter Disc Detective

In 2011, Marc Kuchner (NASA Goddard Space Flight Center) interviewed Zooniverse principal investigator Chris Lintott for a book. Inspired, Kuchner came up with a debris disc search project, which was started in 2014 and continued through 2019.

Now, after a brief hiatus, Disk Detective 2.0 is back online with more data from WISE, as well as data from the European Space Agency’s Gaia mission and the Panoramic Telescope and Rapid Response System.

Disc sleuths identify candidate discs by looking for sources showing more infrared light than expected, the signature of hot gas and dust around the star. Citizen scientists not only select viable disk candidates, but also eliminate false positives from noise and image artifacts.

More than 30,000 members of the public have contributed to the project, including 107 “superusers”. Together, these sleuths have identified more than 50,000 candidate discs. “In other words, our record candidates represent approximately one for every 40,000 sources that WISE has seen,” Kuchner says.

But the Disk Detectives offer so many candidates that those the data can in turn be overwhelming. For example, a team led by Susan Higashio (NASA Goddard Space Flight Center) used custom virtual reality software, PointCloudsVR, developed by Thomas Grubb and designed by Matthew Brandt (also at NASA GSFC) to allow scientists to explore data in a new way.

Susan Higashio uses virtual reality to identify groups of young people on the move
Higashio flies over the Milky Way in virtual reality. In this environment, each star is a labeled point encoded with Gaia’s position and velocity information. The software simulates the 3D motions of stars. The 40,000 stars with disk candidates, found by Disk Detectives, are color-coded, so Higashio can check if any of them coincide with young star clusters. Higashio says “virtual reality is definitely a fun and interactive way to do science!”
NASA / Matthew Brandt

In particular, Higashio targeted associations of stars that all came from the same star-forming region, and therefore all of the same age. Studying the disks in such associations helps determine the timing of planetary formation.

“In VR, you’re immersed in the scene where it’s easier to see star positions, and you can zoom in and out and rotate the scene to get a 360-degree view,” says Higashio, lead author of the paper. of the team to appear in the Astrophysical Journal. “It may be easier to spot these groups.”

Evolution from protoplanetary disk to debris disk
This artist’s depiction shows the evolution from a protoplanetary disk to a debris disk around a young star, a process that takes millions of years. In the upper right, the protoplanetary disk is shiny and filled with dust. It takes about 10 million years for the planets to merge and push their way through the dust. Eventually, as the star’s radiation increases, the protoplanetary disk evolves into a debris disk. Disc sleuths look for the excess infrared light that characterizes both types of discs.

Using this technology, Higashio and his colleagues identified 10 Disk Detective targets belonging to stellar associations, which allowed the researchers to determine the ages of stars between 18 and 133 million years old. “Now we can place them in a time sequence, and they’re part of the story of disk formation and evolution and planet formation and evolution,” Kuchner says.

Join the fun

Other exciting discoveries from the Disk Detective project include a bizarre star – its disk appears to have far too much dust for its age – and a new group of faint young stellars, M dwarfs. Citizen scientist Lisa Stiller says, “It’s exciting that we can use virtual reality to help assess the motions of stars over time and across multiple dimensions. »

You can join the team on the Disk Detective website. All citizen scientists who search for disc candidates in the scientific literature are included as co-authors in journal articles. According to Kuchner, some read thousands of stars in the process. Stiller invites everyone to get involved in the fun of participating in cutting-edge science: “We invite others to join Disk Detective and help find stars that have disks!”

You can also check out other NASA citizen science projects.


About Hannah Schaeffer

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