The outer edges of the solar system constitute a strange and mysterious place. Beyond the orbit of Neptune, where it is cold and dark, a swarm of icy objects called the Kuiper Belt orbits the Sun, which is believed to be more or less unaltered since the birth of the Solar System.
Because it is so dark and distant, and the objects so small, it is difficult for astronomers to discern what exactly is out there. This makes the results of a recent search wonderful. Using data from the Dark Energy Survey, astronomers identified 815 transneptunian objects (TNOs), of which 461 are recently discovered.
This is a significant blow to the more or less known 3,000 TNOs in the outer solar system, information that could help us better model the way the solar system was formed and even search the evasive New Planet.
The new catalog has been submitted for publication and is available on the arXiv prepress server.
“This catalog has 817 confirmed objects (461 first discovered in this work),” the researchers wrote in their article.
“This is the second largest TNO catalog in a survey to date, as well as the largest catalog with multi-band photometry.”
The Dark Energy Survey did not set out to seek TNO. It operated between August 2013 and January 2019, collecting 575 nights of infrared and infrared data close to the southern sky. The goal was to study a series of objects and phenomena such as supernovae and galaxy clusters to try to calculate the acceleration of the expansion of the Universe, which is believed to be influenced by dark energy.
But the high degree of depth, breadth and accuracy of the survey turned out to be very good for looking for objects also in the distant Solar System, beyond the orbit of Neptune at about 30 astronomical units.
Last year, astronomers analyzed this data to find more than 100 new smaller planets, a category that includes basically everything that is not a comet or a planet.
The new work, carried out by the same team and using an improved detection pipe, adds 461 more. The researchers also performed TNO detection simulations to compare them with their results and see if their techniques were accurate.
This region of space is fascinating. With very little to disrupt their orbits, astronomers believe that TNOs retain traces of the dynamics of the first solar system. During this time, according to current models, the planets formed and moved around; the system would have looked very different from how it looks today.
As the giant planets maneuvered into their current orbits, their gravitational interactions influenced the orbits of the TNOs. These resulting orbits can be studied to reconstruct the events that made them this way; as TNO clusters may have quite different orbits, the more we find, the more accurate the reconstruction will be.
Also, the orbits of a subset of TNO are really weird. They are called extreme TNOs, with an average orbital distance (or semi-major axis) greater than 150 astronomical units. Some astronomers believe that extreme TNOs are evidence of something causing a gravitational shock: the hypothetical New Planet.
We haven’t found many of these objects, so all the new ones add an extra data point that could help find or rule out the existence of the New Planet. The new catalog adds nine extreme TNOs to the mix, four of which have semi-major axes in excess of 230 astronomical units.
Researchers also found several objects with orbital resonances with Neptune, which is when bodies have orbital periods with a simple proportion; four new Neptune Trojans, or asteroids that share the planet’s orbit at gravitationally stable Lagrangian points; a large comet called C / 2014 UN271 (Bernardinelli-Bernstein) on a journey into the Sun inland (although it will only reach Saturn before rising again); and a remarkable “separate” object, so named because its orbit is not influenced by Neptune, with an extraordinarily high orbital angle from the plane of the Solar System.
According to the researchers, all this new information represents a significant increase in our understanding of the outer solar system. To date, data from the Dark Energy Survey have contributed about 20 percent of all known TNOs, which is pretty huge.
“These will be valuable for detailed statistical testing of training models for the trans-Neptunian region,” the researchers wrote.
The document has been sent to the AAS and is available on arXiv.