C/2024 E1 (Wierzchoś)
Hyperbolic Oort cloud comet discovered by Kacper Wierzchoś in 2024.
C/2024 E1 (Wierzchoś) is a hyperbolic comet from the Oort cloud, first spotted on 3 March 2024 by Polish astronomer Kacper Wierzchoś. He found it during a routine Mt. Lemmon survey (G96) while examining four 30-second exposures taken with a 1.5-meter Cassegrain telescope. The object appeared at magnitude 20 in the constellation Draco, about two degrees north of the star ν Dra. After the discovery was announced, the Zwicky Transient Facility located precovery images dating back to 15–29 February 2024. The comet initially showed a condensed coma roughly 4 arcseconds across and a tail about 6 arcseconds long. This is the fifth comet Wierzchoś has discovered.
In early 2025, the James Webb Space Telescope observed the comet at a distance of 7.0 AU from the Sun, measuring its infrared spectra and dust production. No carbon monoxide (CO) emission was detected, suggesting the comet lost its near-surface CO early in its history before being ejected to the Oort Cloud. Instead, its activity was driven by carbon dioxide (CO₂). Early brightness predictions suggested it might reach magnitude 5, near naked-eye visibility, but later calculations lowered the peak to magnitude 8.5—about 25 times fainter. By 25 August 2025, the comet was 2.64 AU from both the Sun and Earth. It crossed the celestial equator on 17 November 2025, and on 26 November 2025 it passed about 2.3 degrees southwest of the globular cluster Messier 14.
Perihelion occurred on 20 January 2026 at 18:27 UT, when the comet was 0.566 AU from the Sun. At that time it was about 22 degrees from the Sun, visible from the Southern Hemisphere, and roughly 1.352 AU from Earth. Its peak brightness of magnitude 8.5 made it observable through larger binoculars or a modest telescope. The comet passed 0.191 AU from Venus on 1 January 2026 and came within 1.0 AU of Earth on 17 February 2026. After perihelion and solar conjunction, it was observed on 23 January 2026 at an estimated magnitude of 6.8. By 26 January, its coma had expanded to about 3 arcminutes in diameter and its tail stretched one degree. In mid-February, it displayed a thin ion tail three degrees long and three distinct dust tails spanning nearly 90 degrees.
Between 28 February and 6 March 2026, the comet brightened slightly, then faded rapidly by 0.2 to 0.3 magnitudes per day.
Quick Facts
- Discovery Ref
- CBET_5364
- Discoverer
- Kacper W. Wierzchoś
- Discovery Date
- 3 March 2024
- Discovery Site
- Mount Lemmon Obs.
- Designations
- CK24E010MPEC_2024-E102
- Orbit Ref
- barycenter · jpldata
- Epoch
- 12 May 2025 / (JD 2460807.5)
- Observation Arc
- 763 days (2.09 years)
- Earliest Precovery Date
- 15 February 2024baa-2024
- Obs
- 3,540For the orbital calculations of this comet, only 2,198 observations were used
- Perihelion
- 0.5661 AUperihelion
Facts from the source article.
Lore & Background
C/2024 E1 was first spotted as a 20th-magnitude object in the constellation Draco, about 2 degrees north of the star ν Dra, using a 1.5 m Cassegrain telescope with a 111.5 megapixel CCD. Precovery images were later obtained by the Zwicky Transient Facility from 15 to 29 February 2024. The comet initially had a condensed coma about 4 arcseconds in diameter and a tail about 6 arcseconds long.
Follow-up observations by the James Webb Space Telescope at 7.0 AU from the Sun in early 2025 revealed no emission features for carbon monoxide, indicating the comet may have lost its near-surface CO early in its evolution. Activity was driven by carbon dioxide (CO2). Initial brightness predictions of magnitude 5 were later revised to a peak of 8.5, 25 times fainter. The comet crossed the celestial equator on 17 November 2025 and passed near the globular cluster Messier 14 on 26 November 2025.
At perihelion on 20 January 2026, the comet was 0.566 AU from the Sun and visible from the Southern Hemisphere. It passed 0.191 AU from Venus on 1 January 2026 and 1.0 AU from Earth on 17 February 2026. After perihelion, it displayed a thin ion tail 3 degrees long and three distinct dust tails spanning near 90 degrees. The comet began to disintegrate in March 2026, with its magnitude declining rapidly and losing its central condensation by March 12.
Reader's Guide
C/2024 E1 (Wierzchoś) is significant as a hyperbolic comet from the Oort cloud, providing insights into the composition and evolution of primitive Solar System bodies. Its discovery by Kacper Wierzchoś, the fifth comet he found, highlights the role of amateur and professional collaborations in survey astronomy. The comet's activity being driven solely by carbon dioxide, with no detectable carbon monoxide, suggests that near-surface CO was lost before the comet was ejected to the Oort cloud, offering clues about its thermal history. The revised brightness estimates—from magnitude 5 to 8.5—underscore the challenges in predicting comet behavior. Its post-perihelion disintegration, observed by the Lowell Discovery Telescope, adds to the understanding of cometary fragmentation. The comet's orbital eccentricity slightly greater than 1 indicates it may have enough energy to leave the Solar System, making it a rare example of an interstellar escapee. The James Webb Space Telescope observations at 7.0 AU provided unique infrared spectra and dust production rates, furthering knowledge of distant cometary activity.
Did You Know?
- C/2024 E1 is the fifth comet discovered by Polish astronomer Kacper Wierzchoś.
- The comet's activity is driven by carbon dioxide (CO2), with no detectable carbon monoxide (CO).
More in Named Comets, Part 2 1-24
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