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Every year in late July, Earth plows through a thin ribbon of space dust that nobody knew existed — debris left behind by a comet that has never been seen. A few weeks later, in mid-August, it happens again: a second annual passage through a second ribbon, from a second unknown comet. Both ribbons have now been formally confirmed as meteor showers by the International Astronomical Union, after researchers combing through years of data from the Global Meteor Network (GMN) found the faint but unmistakable statistical fingerprints of two previously unknown streams.
The two showers — M2026-R1 in the constellation Cetus and M2026-S1 in Camelopardalis — were formally registered with the IAU’s Meteor Data Center (MDC) and announced October 31, 2026, in eMetN Meteor Journal’s November issue, the peer-reviewed journal of European meteor research. Both travel on retrograde orbits characteristic of Halley-type comets — meaning their parent bodies, whenever they last made a close pass of the Sun, were moving in the opposite direction to Earth. Both leave annual debris trails that intersect Earth’s orbit, producing predictable if sparse meteor activity each summer. And both matched zero entries in the JPL comet catalog when researchers searched for a source.
Two New Showers Bring the IAU’s Established List to Over 113
The IAU Meteor Data Center currently lists 113 established meteor showers — showers that have cleared the organization’s full review standard. Achieving “established” status requires at least two independent orbit solutions from two separate teams, each with 15 or more confirmed members, along with statistical confirmation that the shower cannot be explained by random coincidence with the background of sporadic meteors that fall every night. M2026-R1 and M2026-S1 are now formally on the Working List, with both papers providing the multi-year evidence base that underpins the registration.
The same November issue of eMetN contains a companion paper formalizing the statistical methodology the GMN team applies to shower candidates, along with confirmations of two additional known showers and a reclassification of a previously registered candidate. It is, in the unassuming arithmetic of the field, a productive month.
M2026-R1: A Barely Detectable Dust Ribbon in Cetus
The first new shower, designated M2026-R1, radiates from the constellation Cetus — the sea monster of Greek mythology, positioned in the southern autumn sky. Its radiant sits at right ascension 36.7° and declination –17.7°, with a geocentric velocity of 63.5 km/s (39.5 miles per second) — fast enough that individual meteors, when they do appear, are expected to leave brief bright streaks. The shower peaks around July 18, at solar longitude 115.5°, with an active window of roughly one day.
Roggemans and his co-authors recovered 49 confirmed members of M2026-R1 from multi-year GMN data, using 98 cameras across 9 countries to map the radiant precisely. The orbital solution that emerged — an eccentricity near 0.920, an inclination of 128.7°, and a perihelion distance of 1.012 AU, just barely outside Earth’s orbit — points firmly to a Halley-type comet as the source. The Tisserand parameter relative to Jupiter comes out at –0.35, a negative value that definitively rules out any connection to Jupiter-family short-period comets and places the orbit in the same dynamic family as the comets that produce the annual Eta Aquariid and Orionid showers.
Roggemans and co-authors describe M2026-R1 as “a barely detectable footprint of a dust remnant of an unknown Halley-type comet” — a phrase that says more than it might at first appear. A footprint of a dust remnant implies that the original comet shed material on enough perihelion passes to build up a strand of debris, and that enough time has passed for that strand to diffuse into a broad, low-density stream. Whether the comet is dormant, extinct, or simply too faint and too infrequently perihelion-bound for current survey programs to have captured it remains unknown.
M2026-S1: A Stronger Signal From the Northern Pole
The second new shower, M2026-S1, is a more substantial detection. It radiates from Camelopardalis — the giraffe constellation near the north celestial pole — at right ascension 93.3° and declination +69.3°. Its geocentric velocity is 54.3 km/s (33.7 miles per second), and its peak falls around August 19, at solar longitude 165.5°, with a confirmed active window of roughly four days. That broader active window, combined with the higher member count, makes M2026-S1 the stronger of the two detections.
Milan Kalina and co-authors recovered 198 confirmed members using the orbit-based identification method and drew on data from 554 GMN cameras for the study. The orbital solution — inclination approximately 100°, eccentricity ranging 0.910 to 0.940, perihelion distance 0.936 to 0.945 AU — again produces Halley-type Tisserand values firmly in Halley-type territory. The authors also discovered that SLY#81 and UYL#705 are duplicates of M2026-S1, a finding that will reduce the number of distinct Working List candidates when IAU administrators act on the paper.
A natural comparison for M2026-S1 is the August Perseids, the year’s most famous meteor shower, which also peaks in mid-August and is produced by the debris of comet 109P/Swift-Tuttle. The orbital similarities extend further: 109P has a perihelion distance of 0.95 AU and an argument of perihelion near 150°, and M2026-S1’s perihelion of 0.94 AU and argument of perihelion of ~149° are close matches. But the inclinations diverge — 113° for Swift-Tuttle versus 100° for M2026-S1 — and the ascending nodes differ enough to confirm there is no connection. M2026-S1 comes from its own unknown comet.
How Do 1,365 Raspberry Pi Cameras Find a Comet Nobody Has Seen?
The Global Meteor Network is, in physical terms, one of the least glamorous-looking major science initiatives running today: a worldwide array of Raspberry Pi single-board computers, each attached to a low-light CMOS video camera, pointing at the night sky from backyards, observatory rooftops, and amateur astronomy clubs in roughly 45 countries. As of the end of 2025, the network comprised 1,365 cameras operated by 927 participating observers, and had accumulated 2,847,823 calibrated meteor orbits since 2018.
Every clear night, each camera runs open-source meteor detection software and transmits detected events to a central archive. A meteor becomes scientifically useful only when it is caught by at least two cameras simultaneously — a “paired” detection — because two angular positions from different ground locations triangulate the meteoroid’s precise 3D path through the atmosphere. From that path plus the known motion of Earth, the software computes the meteoroid’s heliocentric orbit: where it came from in the solar system, how elongated and tilted its path was, how fast it was traveling before it hit the atmosphere.
Those orbits accumulate year over year. The team then applies a statistical procedure called the Drummond D criterion to measure the orbital similarity between any two meteors. Meteors that share similar enough orbits are grouped as candidate shower members. A Poisson probability test then asks whether that many meteors with that much orbital similarity could have occurred by chance given the measured sporadic background rate — the baseline noise of meteors arriving from random directions. For M2026-S1 in the 2026 data alone, the coincidence probability was 5 × 10⁻¹⁵. The signal is not noise.
Once a shower candidate passes those statistical tests across multiple years of data, the team searches the JPL Small Body Database for any known comet or asteroid whose orbit passes within roughly 0.05 astronomical units of Earth’s orbit at the right place and time to be the debris source. For both M2026-R1 and M2026-S1, the search returned nothing. The network has identified 418 showers in total since its founding, and both M2026-R1 and M2026-S1 now join a large set of annual showers with confirmed orbital solutions and no known parents.
What Is a Halley-Type Comet, and Why Can None Be Found for These Showers?
Halley-type comets are a distinct orbital family defined by period — roughly 20 to 200 years between solar passages — and by their orbital inclinations, which can run from nearly zero to well over 90°, including retrograde paths that carry them sunward in the direction opposite to planetary motion. The family is named for 1P/Halley, whose 75-to-76-year period and retrograde orbit Edmond Halley correctly identified in 1705. The most famous meteor showers on the calendar — the Eta Aquariids in May and the Orionids in October — are both produced by debris from 1P/Halley, demonstrating that Halley-type comets can sustain detectably dense debris streams across centuries of solar passages.
As of July 2025, only 109 Halley-type comets have been cataloged. The two new showers imply there are at least two more that science has not yet found. The reason they remain hidden is structural: Halley-type comets spend most of their orbital period in the outer solar system, far from the observational focus of most asteroid and comet survey programs, which are optimized for objects making close approaches to Earth. A comet in a 60-year orbit at 40+ astronomical units from the Sun reflects very little light. If it is also dormant — not actively outgassing and building a visible coma — it looks, from Earth-based telescopes, like a dark rock. A meteor shower it leaves behind from a previous perihelion passage may be the only way to know it passed through at all.
This is exactly the inference that M2026-R1 and M2026-S1 force: both produce annual debris intersections, which means the comet that produced each one shed material on at least several perihelion passes, which means each comet is not newly arrived from the outer solar system but is on a returning short-period orbit. They are out there. They have been coming back for long enough to deposit debris. Telescopes just haven’t found them yet.
Are These the Only Hidden Comets Leaving Annual Debris in Earth’s Path?
Almost certainly not. The 418 showers GMN has identified since 2018 include many with no confirmed parent body, and the network’s growing archive — adding hundreds of thousands of new orbits each year — continues to surface candidates that were invisible to earlier, less comprehensive observation systems. As the archive deepens and more cameras join from currently underrepresented regions of the globe, statistically marginal showers that required multi-year accumulation to confirm will increasingly resolve into confident detections.
The broader implication points in only one direction: the catalog of 109 known Halley-type comets is incomplete, perhaps significantly so. Each new confirmed shower with a Halley-type orbit and no known parent is a data point suggesting the true population is larger. And if the true population is larger, then Earth’s annual schedule of encounters with invisible debris — encounters it has always kept, but has only now begun to read — is richer than any astronomer could have known before a network of Raspberry Pi cameras began watching the sky every night.
Frequently Asked QuestionsWhen can I observe M2026-R1 and M2026-S1?
M2026-R1 peaks around July 18 each year, when Earth reaches solar longitude 115.5°. It is a narrow shower with an active window of roughly one day and a low density of meteors — expect faint, fast streaks appearing to originate from the constellation Cetus in the southern sky. M2026-S1 peaks around August 19 (solar longitude 165.5°) and is active for approximately four days, radiating from Camelopardalis near the north celestial pole. Neither shower is expected to produce the dramatic displays of the Perseids or Leonids; both are subtle annual events better suited to camera networks than casual observation, but both are real, annual, and now confirmed.
How does a meteor shower prove that a comet exists?
When a comet makes repeated close passes of the Sun, heat and solar wind erode its surface and release dust, rock, and ice. That material drifts along the comet’s orbital path and spreads over time into a diffuse stream. If Earth’s orbit intersects that stream, the debris hits the upper atmosphere — typically 80 to 110 km (50 to 68 miles) up — and burns as meteors, all appearing to radiate from the same point in the sky because they are all traveling on the same orbital trajectory. Finding an annual shower whose member orbits match a Halley-type comet’s dynamic signature, while finding no such comet in any existing catalog, constitutes indirect but scientifically valid evidence that the comet exists. It is the debris that gives it away.
Does the discovery of meteor showers from unknown comets mean we might be surprised by a comet approach we didn’t predict?
The existence of Halley-type comets with no catalog entry does raise the theoretical possibility of an untracked object in a returning orbit. However, the two newly confirmed showers provide precise orbital parameters for the debris streams, which in turn constrain the orbital range of the putative parent comets. Neither stream geometry suggests an imminent Earth approach by the parent body. The more likely scenario is that both parent comets are currently in the outer solar system, too distant and too faint for survey telescopes to detect, and will not be observable until they come much closer to the Sun. Backward-computing from a meteor stream orbit to a parent comet has been a tool for targeted comet searches before, and researchers may attempt that with both M2026-R1 and M2026-S1.
Why might the known population of Halley-type comets be significantly underestimated?
As of mid-2025, only 109 Halley-type comets have been confirmed. These are overwhelmingly bodies that came close enough to the Sun — and therefore to Earth — to become bright and optically detectable. A Halley-type comet in a 70-year orbit currently near aphelion, 30 to 50 astronomical units from the Sun, is nearly impossible to detect with most sky survey programs. If it is also dormant — no active outgassing, no visible coma — it reflects almost no light and is effectively invisible. Meteor shower evidence can detect the debris trail such a comet leaves without requiring the comet itself to be observable. The two new showers confirmed in the November 2026 eMetN issue suggest that systematic meteor orbit surveys, now possible at scale through networks like the GMN, may be one of the most productive tools for mapping a comet population that optical surveys have structurally undersampled for decades.