For the first time, astronomers have combined the Hubble and Webb Space Telescopes to search for some of the smallest and faintest objects ever discovered outside the solar system.
This artist’s concept depicts a transsolar system object. Image credit: NASA/ESA/Leah Hustak, STScI.
Two teams of astronomers led by PhD candidates from the University of Victoria and Northern Arizona University used a combination of Hubble’s visible-light vision and Webb’s infrared vision to study 27 newly discovered trans-Neptunian objects (TNOs).
These small objects are icy relics left over from the solar system’s construction phase, before planetesimals coalesced into full-fledged planets.
The smallest are just 5 km (3 miles) wide, and one is so dark that it’s comparable to spotting fireflies on the moon from Earth.
these objects matched The color of its much larger TNO cousin suggests that the surface has not been reshaped by the impact as much as scientists expected.
Astronomers too Found We find that small TNOs are fewer than expected and that both “hot” and “cold” populations of TNOs, sorted by orbital path, share surprisingly similar size distributions, suggesting that planetesimal formation is not very concerned about the conditions of the disk in which it occurs.
“It is very interesting that the process of planetesimal formation ultimately generates distributions of the same size in both cold and hot populations, even though they formed in different regions of the early solar system.” candidate at the University of Victoria.
“This process appears to be independent of disk conditions, producing similar planetesimal sizes whether the disk is hot or cold, dense or fluffy.”
“We can also imagine a scenario in which the surface composition changes upon collision and fragmentation, in which case the surface color of a small TNO is different compared to its larger sibling,” added Dr. Anastasia Morgan. candidate at Northern Arizona University.
“So it’s really interesting to see how the smallest objects somehow ‘remember’ and preserve the history of how they were made.”
“The dynamically ‘hot’ TNO retains traces of its birthplace, even though it has since been scrambled in orbit,” said Northern Arizona University astronomer Dr. David Trilling.
“Both the ‘hot’ and ‘cold’ populations appear to have changed little since the birth of the solar system and remain the same color as when they formed.”
The results are presented in two complementary papers: astronomy magazine.
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Anastasia N. Morgan others. 2026. We combined JWST and HST deep imaging to characterize the smallest known trans-Neptunian object. A.J. 172, 188; doi: 10.3847/1538-3881/ae9084
Mariel R. Eduardo others. 2026. Luminosity functions of ultra faint trans-Neptunian objects detected by JWST. A.J. 172, 187; doi: 10.3847/1538-3881/ae907f
Source: www.sci.news
