(Credit: Simulation Curriculum Corp.)
By late next week, a small comet, fresh off a harrowingly close encounter with the Sun, could emerge into the evening twilight and become easily visible in the hour after sunset, sporting a thin, straight tail. Or this object, known by the prosaic designation C/2026 A1 (MAPS), could totally disintegrate, vaporized by the fierce heat of our star.
Astronomers don’t yet know; based on its behavior and estimated size, it lies on the borderline where either outcome is possible. As comet discoverer David Levy once famously quipped, “Comets are like cats. They both have tails, and they do exactly what they want."
Kreutz Sungrazers: A Dramatic (and Sometimes Suicidal) Comet Family
Comet MAPS belongs to a family of comets, traveling in similar orbits, known as Kreutz sungrazers, which pass precariously close to the Sun and which include many of the brightest comets ever seen; three of them in the past two centuries, the Great Comets of 1843 and 1882, and 1965’s Ikeya-Seki, were visible in full daylight when near the Sun.
Two other notable Kreutz comets, one seen in 1887 and the one found by Australian amateur Terry Lovejoy in 2011, became “headless wonders” after emerging from their solar passage; their nucleus was spent, but they had released enough dust in their disintegration to be easily visible as a bright, narrow ribbon of tail against the night sky.
The Kreutz group is named for Heinrich Kreutz, a German astronomer who determined that several notable nineteenth-century comets traveled in similar orbits and were fragments of a large comet that broke apart (perhaps around the time of the last ice age, it has since been theorized). We know now that the Kreutz group is characterized by a progressive, cascading fragmentation over the millennia of these comets, which can take over a thousand years to orbit the Sun.
It is now believed that Comet MAPS has an orbital period approaching 2,000 years, and may be a fragment of a daylight comet seen in 363 AD. Some Kreutz sungrazers may be related to a bright comet seen in 1106 AD. Other historical comets have been linked to the Kreutz group, including one seen by Aristotle in 372 BC, which was observed to fragment into multiple pieces.
A Lifelong Fascination With Comets
I’ve written a number of solar eclipse-related articles for PCMag, but the objects in the night sky that have most fascinated me over the years are comets; I have visually observed more than 50 of them, and photographed several dozen. My interest in comets was piqued when at a rummage sale, I came across a copy of the 1966 issue of National Geographic with the cover line “Giant Comet Grazes the Sun,” describing Comet Ikeya-Seki’s dramatic apparition and including Tsutomu Seki’s eloquent discovery story (which I see is reprinted in this blog post).
Such was my fascination with these sungrazers that after amateur astronomers started reporting small comets—most of them belonging to the Kreutz family—in images from the Solar and Heliospheric Observatory (SOHO), a joint project managed by NASA and the European Space Agency (ESA), I jumped at the chance to join the hunt for them in what became known as the Sungrazer Project. Over the next five years, I spent more than 1,000 hours scanning SOHO’s images, in which an instrument aboard the satellite, a coronagraph, effectively eclipses the Sun, revealing any objects, including stars, planets, and comets, within its field of view.
I was the first to report many of these micro-comets, most of them fragments of the great Kreutz sungrazers, a few of them impressive in their own right, at least in SOHO's images. But of all those comets I have observed, I have yet to see a Kreutz sungrazer in the night sky and not on a computer screen.
My Pursuit of Comet MAPS
There came a time about a month ago that, based on my experience in photographing other comets with small smart telescopes, I thought I might at least have a shot at photographing MAPS with one or more of these instruments from New York City, but despite multiple attempts, my images came up empty—probably due to the comet’s rapid motion and diffuse nature. Finally, on March 14, I drove out to Compo Beach in my hometown of Westport, Connecticut, and managed to photograph MAPS, both with my large scope (Celestron Origin Mark II) and one of the small ones (Dwarflab Dwarf 3). I was thrilled to have finally caught a Kreutz sungrazer with my own equipment.
(Credit: Tony Hoffman)If indeed comets are like cats, Comet MAPS appeared Manx-like but distinctly green, a fuzzball (as astronomers are wont to call a small, tailless—or nearly so—comet) in my image from the Celestron Origin. As it turned out, based on my own work schedule and its declining altitude as it slipped into and finally was lost in the sunset glare, I photographed it on the last day that it would have been possible for me to do so.
The Comet Makes a Run at the Sun
Comet MAPS, whose name is an acronym of the last initials of the four participants (Alain Maury, Georges Attard, Daniel Parrott, and Florian Signoret) in a sky survey based in Maury's observatory in Chile, was discovered on Jan. 13 at a record distance from the Sun for a Kreutz sungrazer. From February into March, it was brightening rapidly, and astronomers hoped for extreme brightness around its time of perihelion. After its rate of brightening decreased in late March, they have largely tempered their expectations, and now the question is whether it will even survive its perihelion passage (its closest approach to the Sun). It is now too close to the Sun to be observed or photographed from the ground, but space-based telescopes are keeping an eye on it.
On Thursday, April 2, the comet will enter the field of view of SOHO’s LASCO C3 coronagraph (the blue image on the right) at about the 8 o'clock position to start its two-day sprint toward the Sun. On Saturday, it will pass less than a quarter of a solar radius from the Sun’s photosphere (surface) as it makes a hairpin turn around our star and heads back roughly in the direction whence it came. Then we will see what, if anything, emerges, first in the narrow-field C2 (orange) images, then in the C3 coronagraph images, and later in the night sky.
Astronomers have discussed three possible outcomes. MAPS could survive its solar passage (aka perihelion) with its nucleus greatly diminished but intact, appearing in the western sky in evening twilight to the left of the sunset point, likely developing a straight, narrow, and perhaps long tail, pointing to the upper left away from the sunset point. Alternatively, its tiny nucleus, believed to have been 0.4km (about a quarter of a mile) in diameter when it was imaged by the James Webb Space Telescope on Feb. 7, could disintegrate and become vaporized before it ever reaches the Sun. The third possibility is that it could disintegrate just after perihelion, releasing enough dust to become a “headless wonder.” Most of the talk among astronomers lately has been about the second and third possibilities, but I’d prefer to let the comet write its own story.
(Credit: Simulation Curriculum Corp.)Viewing Comet MAPS—If It Survives
If it survives, it could emerge from the solar glare by the end of next week. News reports should indicate if it survives. I have included a pair of finder charts, the article's lead image for April 9, and the one shown just above April 12, for about an hour after sunset at the latitude of New York. (For more southerly locations, the comet would be higher in the sky relative to the Sun. Farther north, and the comet would be closer to the horizon.)
The green line represents the horizon, and the comet would be to the left of the sunset point, to the lower left of Venus. If it is visible, it may be distinguishable by a straight, narrow tail, extending in the anti-sunward direction (to the comet's upper left). Binoculars may be helpful, but they probably wouldn't be necessary to spot it. Whether or not MAPS fizzles, another comet, C/2025 R3 (PANSTARRS), is approaching naked-eye visibility in the morning sky and should be at its best later in April.