6-year search of the outer solar system reveals 461 new objects (but no planet 9)
In the near future, astronomers will benefit from the presence of new generation telescopes like the James Webb Space Telescope (JWST) and the Nancy Grace Roman Space Telescope (RST). At the same time, improved data mining and machine learning techniques will also allow astronomers to get the most out of existing instruments. In the process, they hope to finally answer some of the most burning questions about the cosmos.
For example, the Dark Energy Survey (DES), an international collaborative effort to map the cosmos, recently released the results of its six-year survey of the Outer Solar System. In addition to collecting data on hundreds of known objects, this investigation revealed 461 previously undetected objects. The results of this study could have important implications for our understanding of the formation and evolution of the solar system.
The research was led by Dr. Pedro Bernardinelli, a Ph.D. candidate in the Department of Physics and Astronomy at the University of Pennsylvania (UPenn). He was joined by Gary Bernstein and Masao Sako (two professors in the Department of Physics and Astronomy at UPenn) and other members of the DES Collaboration. Beginning in 2013, DES seeks to determine the role dark energy has played (and continues to play) in the expansion and evolution of the cosmos.
Between 2013 and 2019, DES used the 4m Blanco telescope at the Inter-American Observatory of Cerro Tololo (CTIO) in Chile to study hundreds of millions of galaxies, supernovae, and the large-scale structure of the Universe. While their primary goal is to measure the rate of acceleration of cosmic expansion (aka the Hubble-LemaÃ®tre constant) and the spatial distribution of dark matter, the DES collaboration has also reported the discovery of individual TNOs of interest. . As Dr Bernardinelli explained to Universe Today via email:
âAn important detail is that when you take a picture of the sky, you not only see what you are looking for, but you also see other things that are in the same region of the sky that may be closer to or further away from. your target. So we can see anything from planes and asteroids to the NWT, as well as distant stars and galaxies. So we can use the data to find other things (in my case, the NWT!) â
Their results were described in a previous study, where the DES collaboration shared the first four years of data collection (“Y4”). This led to the discovery of 316 individual TNOs of interest and the development of new machine learning techniques for TNO research. On this basis, the team analyzed the results of the full six years of DES survey data (âY6â) for the NWT, with some modifications and improvements.
This included adopting the initial version of the TNO pipeline (the one used for Y4) but with a series of algorithmic changes. They also reprocessed the Y4 catalog to detect weaker objects and increased the computing power involved. As a result, the Y6 catalog was considerably larger than the Y4, which was the biggest difference (and challenge) between the two surveys. In a sense, Dr Bernardinelli said, the Y4 research was a dress rehearsal for the Y6 research:
âAll of these technological developments present some unique challenges for DES, as we are, again, not a solar system project, so we had to find new ways to search for these objects (usually TNO surveys have multiple images per night we only have one). I like to describe this problem as âfinding a nail in a haystackâ mixed with âconnecting the dotsâ (you have to find the 10 points out of 100 million that correspond to a single object – these are real numbers!). So everything we have done will help future projects that have similar challenges.
This time, the Collaboration detected 461 previously undetected objects, bringing the total number of TNOs discovered by DES to 777 and the number of known TNOs to nearly 4,000. They also obtained new data on many other objects, including the great comet C / 2014 UN271, which Dr Bernardinelli and co-author Prof. Bernstein discovered in 2014 while examining some of the DES archival footage. Dr Bernardinelli said:
âAll of these technological developments present some unique challenges for DES, as we are, again, not a solar system project, so we had to find new ways to search for these objects (usually TNO surveys have multiple images per night we only have one). I like to describe this problem as âfinding a nail in a haystackâ mixed with âconnecting the dotsâ (you have to find the 10 points out of 100 million that correspond to a single object – these are real numbers!). So everything we’ve done will help future projects that have similar challenges.
The implications of this research are both broad and important. For starters, astronomers have long suspected that the population of small bodies orbiting beyond Neptune is a holdover from the formation of the solar system. In addition, the current orbital distribution of these objects is the result of the migration of
giant planets in their current orbits. During their migration, they sent these objects to the Transneptunian region.
“[W]We can use these objects to try to trace this story. By collecting data on hundreds of these objects, therefore, we can ask all kinds of questions, such as “How fast did Neptune migrate?” “(Our data shows a preference for slower migration) or” is there a ninth planet hidden on the outskirts of the solar system? (our data doesn’t show the expected signal, but that doesn’t mean we’re ruling out the idea of ââplanet 9).
In short, by identifying the NWT and limiting their orbital dynamics, astronomers will be able to gain new knowledge about how our solar system formed and evolved billions of years ago. This knowledge could also inform our understanding of how the habitable systems that give birth to life emerge, making it easier for us to find it!
Further reading: arXiv