New Giant Comet Candidate Discovered: Will It Become a Naked-Eye Comet in 2028?
A newly discovered comet candidate is already making astronomers nervous — in a good way. A11yzTN appears to be surprisingly large, possibly the size of a city. If things go well, it could become much brighter as it heads toward the Sun in November 2028 — possibly even bright enough to see without a telescope. That is why A11yzTN is quickly turning from a faint dot in the data into one of the most intriguing objects to watch. And if you want to follow where it is in the sky and check whether it will be visible from your location, Sky Tonight makes it easy to keep track of the comet as the story unfolds.
Contents
- Comet A11yzTN: basic facts
- What Is Comet A11yzTN?
- When and Where to See Comet A11yzTN?
- What Do We Know About Comet A11yzTN Orbit?
- How Was Comet A11yzTN Discovered?
- Bottom Line: Why Comet A11yzTN Is Worth Following
Comet A11yzTN: basic facts
- Type: long-period comet candidate
- Estimated perihelion date: around November 2028
- Estimated perihelion distance: about 1.1–1.2 AU
- Orbital inclination: close to 100°
- Nucleus size: ~20–40 km (very preliminary estimate)
- Possible brightness: roughly magnitude 8-9; under favorable conditions it could possibly become brighter (up to magnitude 2)
Technically, A11yzTN is still a comet candidate, meaning its nature is still being confirmed. For readability, we refer to it simply as a comet throughout this article.
What Is Comet A11yzTN?
A11yzTN is a newly discovered long-period comet candidate that has already drawn attention because it was spotted far beyond Saturn’s orbit — at roughly 10 AU from the Sun — while still shining at about magnitude 19. That may sound faint, but for such a distant object, it is enough to suggest that the comet could be unusually large — which is exactly why astronomers are watching it so closely. Only a few comets have been discovered at even greater distances — for example, C/2014 UN271 (Bernardinelli–Bernstein), first detected nearly 30 AU from the Sun.
If early estimates hold up, A11yzTN could become much brighter as it approaches the Sun and may turn into one of the most exciting comets to follow in 2028.
How Big Is Comet A11yzTN?
Astronomers cannot measure the exact size of Comet A11yzTN yet, but its brightness at such a huge distance hints that the nucleus could be very large — possibly around 20–40 kilometers across — roughly the width of a large city. For comparison, Comet 67P/Churyumov-Gerasimenko — the first comet ever visited and landed on by a spacecraft — has a nucleus about 4 km wide. Comet C/1995 O1 (Hale-Bopp), one of the most spectacular naked-eye comets of the late 20th century, is estimated to have had a nucleus about 60 km across. The largest known comet nucleus belongs to C/2014 UN271 (Bernardinelli–Bernstein), estimated to be roughly 120–150 km across (that giant will reach perihelion only in January 2031 and stay about 10.95 AU from the Sun — far too distant to put on the kind of bright show skywatchers usually hope for). So A11yzTN may not be the record-holder — but it could still be a genuinely big comet.
Will Comet A11yzTN Hit Earth?
Any unusually large object inevitably raises this question. So here is the answer: no, Comet A11yzTN is not expected to hit Earth. Current orbital calculations show that the comet will remain far from our planet throughout its passage through the inner Solar System. In other words, however big or bright it may turn out to be, it is interesting as a sky event — not as a threat.
Although comet impacts are theoretically possible, they are extremely rare on human timescales. So A11yzTN is interesting not because it poses any danger, but because comets themselves are among the Solar System’s most dramatic and mysterious visitors. To learn more about their nature, origins, and behavior, read our article on what comets are.
When and Where to See Comet A11yzTN?
For now, Comet A11yzTN is far too faint for casual observing: at around magnitude 19, it remains a target for large professional telescopes rather than backyard stargazers. The real action is expected much later, as the comet moves inward toward its November 2028 perihelion.
- More cautious early estimates suggest it could brighten to around magnitude 8–9, which would make it a good target for small telescopes or binoculars.
- But some more optimistic discussions suggest that, if the comet is truly large and develops strong activity, it could become significantly brighter than that, possibly even reaching naked-eye visibility under favorable conditions (around magnitude 2).
Current projections also suggest that the best viewing conditions may favor the Southern Hemisphere, especially near peak brightness.
Will Comet A11yzTN Be Visible to The Naked Eye?
There are good reasons to think that A11yzTN will be visible to the naked eye:
- First, A11yzTN was detected at a huge distance — beyond Saturn’s orbit — while still shining at about magnitude 19, which hints that it could be a physically large comet.
- Second, early images do not show a dramatic coma, suggesting that the object may still be only weakly active for now. If so, that makes the size estimates more interesting: a large nucleus has more ice and dust to release as it warms up, giving the comet a better chance to brighten strongly near the Sun.
- Finally, A11yzTN is expected to pass the Sun at a distance of about 1.1–1.2 AU, close enough for solar heating to potentially trigger a strong rise in activity.
None of this guarantees a spectacular display — but it does explain why naked-eye visibility is considered a real possibility.
Could A11yzTN become the next truly great comet? It is too early to say — but the possibility is part of the excitement. And while we wait for 2028, take our Great Comets quiz and revisit some of the most spectacular celestial visitors in history, including the unforgettable Hale-Bopp.
What Do We Know About Comet A11yzTN Orbit?
Current calculations suggest that A11yzTN is a long-period comet candidate traveling on a highly elongated orbit that brings it in from the distant outer Solar System toward the inner planetary region.
Its orbit is also steeply tilted — with an inclination close to 100° — which means it does not move through space in the same relatively flat plane as the planets. Comets with this kind of trajectory are often thought to come from the Oort Cloud, a vast reservoir of icy bodies far beyond the known planets. That kind of orbit is typical of comets that spend most of their time far beyond the planets and only briefly visit the inner Solar System.
Right now, A11yzTN is expected to reach perihelion, its closest point to the Sun, in November 2028, passing at a distance of about 1.1–1.2 AU.
How Was Comet A11yzTN Discovered?
Comet A11yzTN was first identified in February 2026 in observations linked to the Purple Mountain Observatory (Tsuchinshan) and later picked up independently by the ATLAS survey. After the initial detection, astronomers found earlier “precovery” images of the object in archival observations dating back to December 2025, which helped refine its orbit. Then, after additional follow-up observations, the object was added to the comet confirmation page, drawing wider attention from astronomers around the world. If its cometary nature is fully confirmed and it eventually receives a formal name, we may end up with another Tsuchinshan–ATLAS comet — and it would be especially exciting if this one turned out to be as bright and memorable as the famous Tsuchinshan–ATLAS visitor, also known as the Great Comet of 2024.
Bottom Line: Why Comet A11yzTN Is Worth Following
Comet candidate A11yzTN was discovered beyond Saturn’s orbit in February 2026. Early estimates suggest it may have a very large nucleus — around 20–40 km across — making it much bigger than many ordinary comets. Most importantly, it has a real chance to become bright enough to see without a telescope as it approaches the Sun in November 2028. That does not mean a spectacular show is guaranteed — comets are famously unpredictable — but A11yzTN already looks like the kind of object that could turn into a major sky event. And if you want to follow its path and check whether it is visible from your location, Sky Tonight is an easy way to keep an eye on it as the story unfolds.
Comets to See Right Now
While we wait to see how Comet A11yzTN develops, there is no need to put comet watching on hold. Take a look at our article on upcoming comets to see which other visitors are heading our way and when to look for them.
