Sungrazing Comet MAPS Skims the Sun, Leaving Astronomers Waiting to See if It Survived

At 14:23:36 Coordinated Universal Time on Saturday, a chunk of ice and dust less than half a mile wide swept past the blistering surface of the Sun at more than 2 million mph, just 150,000 to 160,000 kilometers above the solar photosphere.

The object, Comet C/2026 A1 (MAPS), is a so‑called sungrazing comet, a rare member of the Kreutz family whose orbits carry them deep into the Sun’s outer atmosphere. As the comet skimmed through that hostile environment, scientists could not yet say whether it would emerge intact—or disintegrate into a cloud of dust.

Around the world, researchers and amateur skywatchers alike were refreshing real‑time images from NASA’s Solar and Heliospheric Observatory (SOHO) and other solar spacecraft, hoping to see whether MAPS survived its closest approach or was torn apart.

A tiny comet in a very hot seat

Astronomers calculate that MAPS reached its closest point to the Sun, or perihelion, at 10:23 a.m. EDT Saturday. Its orbit takes it to a distance of about 0.00573 astronomical unit from the Sun—just 1.23 solar radii from the Sun’s center, or roughly a quarter of a solar radius above the visible surface.

That trajectory places the comet inside the low solar corona, where temperatures soar to more than a million degrees Fahrenheit and the Sun’s gravitational tides and radiation bombard any icy body that ventures too close.

“This really is a make‑or‑break passage,” said Qicheng Zhang, a comet researcher at Lowell Observatory who led early observations of MAPS with the James Webb Space Telescope. “Based on its size, it is big enough that it could come out the other side, but small enough that total disruption is still very much on the table.”

In February, Zhang’s team used Webb’s Mid‑Infrared Instrument to get a rare direct measurement of the comet’s solid nucleus. They estimated a diameter of about 0.38 kilometer, with an uncertainty of about 0.07 kilometer—roughly a quarter of a mile across.

That measurement makes MAPS similar in size to Comet C/2011 W3 (Lovejoy), another Kreutz sungrazer that survived a close solar pass in 2011 before breaking apart days later. But MAPS is intrinsically fainter than some of the most spectacular sungrazers of the past, such as the Great Comet Ikeya‑Seki of 1965, and its extremely tight swing past the Sun raises doubts about whether it can hold together.

Daniel Green of the Central Bureau for Astronomical Telegrams, which publishes official notices on new comets, has warned that MAPS’ intrinsic faintness is a bad sign.

“The faint absolute magnitude of C/2026 A1 (MAPS) does not bode well for the comet’s survival past perihelion,” Green wrote in an early circular.

Other observers urged caution in making firm predictions. Czech comet watcher Jakub Černý, writing in a social media group for comet observers, called Kreutz sungrazers “an extremely special case” where standard brightness rules do not always apply. He suggested MAPS appeared to be a mid‑sized member of the family and might survive at least the passage around the Sun—perhaps emerging as a bright naked‑eye object—even if its inner core was damaged.

From a desert telescope to a front‑row seat on Webb

Comet MAPS was first spotted just before dawn on Jan. 13 by a small, independent survey in northern Chile. Working from the AMACS1 Observatory near San Pedro de Atacama, French astronomer Alain Maury and collaborators Georges Attard, Daniel Parrott and Florian Signoret were scanning the sky with a 0.28‑meter Schmidt telescope when a faint, moving point appeared in the constellation Columba.

The team’s surnames—Maury, Attard, Parrott, Signoret—gave the comet its name. Within a week, the Minor Planet Center had issued its official designation, C/2026 A1 (MAPS), in a Minor Planet Electronic Circular and a Central Bureau Electronic Telegram.

Right away, orbit calculations showed that this was not just any new comet. Even though it was then 2.056 astronomical units from the Sun—about 308 million kilometers away—its path was clearly that of a Kreutz sungrazer: a highly elongated, retrograde orbit inclined about 144 degrees to the plane of the planets and plunging deep into the inner solar system.

At that discovery distance, MAPS became the most distant inbound Kreutz sungrazer ever identified. The last such comets of comparable brightness, including Lovejoy, had been found only days or even hours before perihelion, and most members of the Kreutz family are so small they are only seen as fleeting streaks in SOHO’s coronagraph cameras.

The extra lead time—roughly 11 weeks from discovery to perihelion—allowed astronomers to line up an unusually comprehensive observing campaign. In early February, Webb targeted MAPS with its infrared instruments. Large ground‑based telescopes and networks of smaller observatories followed up in visible light, while amateur observers contributed brightness measurements to international databases.

“This is the first time we’ve been able to watch a Kreutz sungrazer evolve all the way in from 2 astronomical units,” Zhang said. “We’re finally seeing how one of these objects behaves well before it enters the field of view of SOHO.”

A fragile brightening, then worrying signs

Throughout February and into March, observers watched MAPS steadily brighten as it fell toward the Sun. It rose from about 17th magnitude—far too faint to see without a substantial telescope—toward magnitude 11 and brighter, eventually becoming an accessible target for serious amateur instruments in southern skies as it moved through Eridanus and Cetus.

By late March, though, several observers reported that the comet’s brightening had stalled. Some measures even suggested a slight fading compared with earlier projections. Online forums lit up with suggestions that MAPS might be fragmenting under increasing solar heating.

Threads with titles such as “Sungrazing comet MAPS is in serious trouble” circulated among comet enthusiasts, citing changes in the comet’s inner coma and a less condensed central “head.” Others pointed out that observing geometry was becoming more difficult as the comet drew closer to the Sun, increasing the likelihood of noisy measurements.

Specialist sites that model comet brightening curves, including those that factor in forward scattering of sunlight off dust particles, updated their forecasts repeatedly as fresh data arrived. Many scenarios still allowed for a sharp surge in brightness in the final days and hours before perihelion if MAPS shed large amounts of dust.

That dust could, in principle, make the comet reach negative magnitudes comparable to or even brighter than Venus when viewed at small angles from the Sun—bright enough to qualify as a “daylight comet.” But from the ground, the comet’s proximity to the Sun on the sky would render it effectively invisible to the unaided eye and too dangerous to hunt with binoculars or telescopes.

Astronomy groups and science outlets repeatedly warned against trying to spot MAPS in broad daylight or near the Sun without proper solar filters, stressing the risk of permanent eye damage.

A comet family with a long memory

Kreutz sungrazers like MAPS are believed to be fragments of a giant progenitor comet that broke apart centuries ago, possibly seen by ancient observers as early as 371 B.C. and again in A.D. 1106. Later generations produced some of the brightest comets in recorded history, including the Great Comet of 1843 and the Great September Comet of 1882, both visible in broad daylight.

Since the advent of space‑based coronagraphs in the late 20th century, spacecraft such as SOHO have detected thousands more Kreutz fragments—most only a few meters across—as they race into the corona and vaporize. More than 3,500 of SOHO’s more than 5,000 comet findings are members of this family.

What sets MAPS apart is its size and early discovery. Unlike the anonymous specks that flash through SOHO images, its nucleus is large enough to be studied as a physical body before its encounter with the Sun. And because it was picked up months before perihelion by a comparatively modest ground‑based telescope, scientists have been able to coordinate a program that spans wavelengths from infrared to visible light.

Watching the outcome, whatever it is

As MAPS passed perihelion Saturday, its icy nucleus, if still intact, would have been subjected to violent outgassing as frozen water, carbon dioxide and other volatiles erupted off its surface. Uneven jets can torque a comet, potentially spinning it faster than its structure can withstand, while intense tidal forces near the Sun can stress already‑fractured interiors.

In the hours and days after closest approach, solar observatories will show whether a compact comet head emerges from behind the occulting disks of their coronagraphs or whether only a diffuse trail of dust remains.

If MAPS survives, it is expected to move into the evening sky in early to mid‑April, initially low over the western horizon after sunset. Under favorable circumstances, models suggest it could display a long, fanlike tail stretching 10 to 30 degrees across the sky, though its exact brightness remains uncertain. If instead it disintegrates near perihelion, observers may see a “headless” streak of dust sliding away from the Sun, with no sharp central condensation.

For scientists, either outcome offers valuable data. A surviving nucleus would allow studies of how its surface and activity change after the extreme heating of a solar grazing. A complete breakup would help refine estimates of the strength and internal structure of small cometary nuclei and shed light on why some Kreutz fragments endure while most are destroyed.

“This is a rare natural experiment,” Zhang said. “We have a well‑characterized nucleus going into one of the most extreme environments in the solar system. Whatever happens to MAPS, we will learn a great deal about how these sungrazing comets live and die.”

For now, that verdict lies hidden in the glow of the solar corona, as a world of watchers waits to see whether a quarter‑mile‑wide relic of the early solar system can withstand a near‑miss with the Sun.