Qurexa Logo
Qurexa

Trust. Care. Deliver.

Back to Blog & Insights
Technology

Spotted on a crowded patch of sky, 46 times further out than we are: a new dwarf planet candidate

Qurexa Editorial Team28 October 20266 min read 0 0
Spotted on a crowded patch of sky, 46 times further out than we are: a new dwarf planet candidate

What happened

On Monday 27 October 2026, the NSF and DOE Vera C. Rubin Observatory announced its first dwarf planet candidate. The object has been given the provisional name 2026 ED138. The observations were released through the International Astronomical Union's Minor Planet Center, which is the body that records and names small bodies in the solar system. It was found on the evening of 13 October by Matthew Holman, of the Center for Astrophysics, Harvard and Smithsonian, who works on the Rubin operations team. He was running a piece of search code he had developed with Kevin Napier. The code sifts through billions of detections of moving points of light and works out which ones belong to the same object. Holman described his first reaction as excited disbelief. Mario Jurić, Rubin's lead scientist for the solar system, then went back through Rubin's catalogues and images and found another 20 sightings. In total the telescope had recorded the object 30 times across 20 nights between 4 March and 11 July 2026, without anyone noticing. Older pictures from the Dark Energy Camera, tracked down using the Asteroid Institute's precovery service, push the record back to 2016. The team now has more than ten years of its path through the sky.

Why this matters

This is a story about a new telescope doing precisely what it was built to do, very early on. Rubin's main survey, the Legacy Survey of Space and Time, only began in June 2026. Before it formally started, the solar system team had already submitted more than 11,000 new asteroids to the Minor Planet Center, including around 380 new objects beyond Neptune. Finding a dwarf planet candidate within months of switching on says something about the step change in capability. There is a second point that is easy to miss. This object was hard to see not because it is unusually faint, but because of where it sits in the sky. It lies near the crowded plane of the Milky Way, where the background is packed with stars. Picking out one slow-moving dot against that mess is a software problem as much as a telescope problem. That is the real advance here. The observatory produces so much data that the discoveries come from code that knows what to look for. Holman found it by running a search. Jurić found twenty more sightings by searching back through records already held. Nobody had to point a telescope anywhere new. Jurić put it neatly: once a new object is identified, the team can search back months, and sometimes even decades.

What the evidence actually says

Here is what is known, and what is not. The object is currently about 46 astronomical units from the Sun. An astronomical unit is the distance from the Earth to the Sun. Pluto averages about 40, so 2026 ED138 is further out than Pluto. Its orbit is tilted roughly 25 degrees away from the flat plane that most of the solar system sits in. That makes it what astronomers call a hot classical trans-Neptunian object, and it suggests Neptune's gravity knocked it off its original course a very long time ago. The size estimate is where the caution comes in. Based on how far away it is, how bright it appears, and an assumption about how reflective its surface is, the team estimates a diameter somewhere between 600 and 1,500 kilometres. That is a wide range, and it is wide because nobody knows the reflectivity yet. Size matters because it decides the question. Icy bodies that large are expected to be pulled into a round shape by their own gravity, and being round is one of the criteria for being a dwarf planet. So this is a candidate, not a confirmed dwarf planet. Infrared observations are needed to pin down the size and settle it. If confirmed, it would join Pluto, Ceres, Eris, Haumea and Makemake, which is a very short list. Holman was careful about the wording himself, saying that if confirmed as a dwarf planet, ED138 would join a very small family of worlds.

Practical advice

You cannot see this object. It is far too faint for any ordinary telescope. But there are things worth doing if the story interests you. The team has made the object's orbit viewable in 3D through Rubin's Orbitviewer app, which is free to use and runs in a browser. It is a genuinely good way to get a feel for how far out 46 astronomical units actually is. If you have a child or grandchild who likes space, this is an unusually good example to show them. It involves no spacecraft and no rocket. It is a person writing code, running it over existing pictures, and finding a world. That is what a lot of modern astronomy actually looks like. If you want to follow what happens next, the Minor Planet Center publishes new observations and designations, and Rubin Observatory posts updates on its own site. Confirmation, if it comes, will take time. And if you want to look at something real tonight instead, autumn is a good season for stargazing in Lincolnshire. Clear nights, long darkness, and no equipment needed to see Jupiter or the Pleiades.

What to know

The Vera C. Rubin Observatory has announced its first dwarf planet candidate, provisionally named 2026 ED138, through the IAU Minor Planet Center on 27 October 2026. It was found on 13 October by Matthew Holman, running search software over Rubin data. The telescope had already recorded it 30 times across 20 nights without anyone noticing, and archive images extend its known path back to 2016. It sits about 46 astronomical units from the Sun, further out than Pluto, on an orbit tilted about 25 degrees. Its estimated diameter is 600 to 1,500 kilometres. That range is too wide to confirm dwarf planet status, and infrared observations are needed. Rubin's main survey only began in June 2026, which makes this an early sign of what the observatory is likely to turn up over the next decade. Sources: SLAC National Accelerator Laboratory, 'NSF–DOE Vera C. Rubin Observatory reveals its first dwarf planet candidate in our solar system', 27 October 2026, https://www6.slac.stanford.edu/news/2026-10-27-nsf-doe-vera-c-rubin-observatory-reveals-its-first-dwarf-planet-candidate-our-solar ; Phys.org, 'Rubin Observatory reveals its first dwarf planet candidate in our solar system', 27 October 2026, https://phys.org/news/2026-10-rubin-observatory-reveals-dwarf-planet.html ; Vera C. Rubin Observatory, https://rubinobservatory.org/

#astronomy#Rubin Observatory#dwarf planet#solar system#telescopes#research

Related articles