Zero Genie

Astronomers have released a catalog of 316 trans-Neptunian objects (TNOs) — minor planets located in the far reaches of the Solar System — detected from the first four years of the Dark Energy Survey (DES). The new catalog includes 245 discoveries by DES, 139 not previously published.

An artist’s impression of a trans-Neptunian object. Image credit: NASA / ESA / G. Bacon, STScI.

The goal of DES, which completed six years of data collection in January 2020, is to understand the nature of dark energy by collecting high-precision images of the southern sky.

While the survey wasn’t specifically designed with TNOs in mind, its breadth and depth of coverage made it particularly adept at finding new objects beyond Neptune.

“The number of TNOs you can find depends on how much of the sky you look at and what’s the faintest thing you can find,” said University of Pennsylvania’s Professor Gary Bernstein.

Because DES was designed to study galaxies and supernovas, the astronomers had to develop a new way to track movement.

Dedicated TNO surveys take measurements as frequently as every hour or two, which allows researchers to more easily track their movements.

“Dedicated TNO surveys have a way of seeing the object move, and it’s easy to track them down,” said Pedro Bernardinelli, a graduate student at the University of Pennsylvania.

“One of the key things we did in this paper was figure out a way to recover those movements.”

The team analyzed data from the first four years of DES and found 316 TNOs, including 245 discoveries made by the survey and 139 new objects that were not previously published.

With only 3,000 objects currently known, this DES catalog represents 10% of all known TNOs.

Pluto, the best-known TNO, is 40 times farther away from the Sun than Earth is, and the TNOs found using the DES data range from 30 to 90 times Earth’s distance from the Sun.

Some of these objects are on extremely long-distance orbits that will carry them far beyond Pluto.

The new catalog will be a useful scientific tool for research about the Solar System.

Because DES collects a wide spectrum of data on each detected object, astronomers can attempt to figure out where the TNO originated from, since objects that form more closely to the Sun have are expected to have different colors than those that originated in more distant and colder locations.

And, by studying the orbits of these objects, they might be one step closer to finding Planet Nine, a hypothesized Neptune-sized planet that’s thought to exist beyond Pluto.

“There are lots of ideas about giant planets that used to be in the Solar System and aren’t there anymore, or planets that are far away and massive but too faint for us to have noticed yet,” Professor Bernstein said.

“Making the catalog is the fun discovery part. Then when you create this resource; you can compare what you did find to what somebody’s theory said you should find.”

The team’s paper was published in the Astrophysical Journal Supplement Series.

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Pedro H. Bernardinelli et al. 2020. Trans-Neptunian Objects Found in the First Four Years of the Dark Energy Survey. ApJS 247, 32; doi: 10.3847/1538-4365/ab6bd8