Comet C/2023 A3 (Tsuchinshan-ATLAS) is one of the most anticipated celestial events of 2024. Discovered in early 2023, this comet has generated significant excitement among astronomers and skywatchers due to its potential to become a spectacular object in the night sky. In this article, we’ll delve into the comet’s discovery, observations so far, and the best opportunities to observe it in the coming months.
Discovery of Comet C/2023 A3 (Tsuchinshan-ATLAS)
Comet C/2023 A3 was independently discovered by two different observatories: the Purple Mountain Observatory in China (known as Tsuchinshan, which means “Purple Mountain” in Chinese) and the ATLAS (Asteroid Terrestrial-impact Last Alert System) project based in Hawaii.
- Tsuchinshan Discovery: The comet was first spotted on January 9, 2023, by astronomers at the Purple Mountain Observatory. This facility has a long history of comet discovery, with C/2023 A3 being one of its most promising finds in recent years.
- ATLAS Discovery: On February 22, 2023, the ATLAS survey also independently discovered the comet. ATLAS is a system designed to detect near-Earth objects, and its discovery added credibility to the early observations.
After these independent discoveries, the comet was designated C/2023 A3 (Tsuchinshan-ATLAS), combining the names of the two observatories. Early calculations of its orbit indicate that it would pass relatively close to the Sun at a distance of 0.39 AU (about 58 million kilometers or 36 million miles) and could potentially become a very bright object.
Observations So Far
Since its discovery, Comet C/2023 A3 has been under close observation by astronomers worldwide. As it moves closer to the Sun, its brightness has steadily increased, and its coma (the cloud of gas and dust surrounding its nucleus) has become more prominent. There have been recent conflicting views about this comet’s potential brightness, however. Read more about this further below.
Early Observations
In the months following its discovery, the comet was monitored closely as it moved through the outer regions of the solar system. Initially, the comet’s magnitude was quite faint, around magnitude 18.8 when it was discovered in January 2023 by the Purple Mountain Observatory. As it moved closer to the Sun, its brightness gradually increased.
- March 2023: Observations by amateur astronomers, including reports on the Comet Observers database (COBS), recorded the comet’s brightness at around magnitude 17.5 to 17.0.
- April 2023: The comet continued to brighten steadily, reaching a magnitude of around 16.5 by mid-April. This was confirmed by observations from the ATLAS survey, as well as independent measurements by amateur astronomers using CCD imaging.
- June 2023: By mid-year, the comet’s brightness was estimated at magnitude 15.0, as reported by several observers, including those using the Las Cumbres Observatory Global Telescope Network (LCOGT).
These early observations were crucial in refining the comet’s predicted orbit and brightness curve, leading to more accurate forecasts of its potential visibility as it approaches perihelion.
Recent Observations
As of mid-2024, Comet C/2023 A3 has brightened significantly, becoming more accessible to amateur astronomers equipped with moderate telescopes. Recent observations have tracked the comet’s increasing brightness as it approaches the inner solar system.
- May 2024: The comet’s brightness was reported at around magnitude 12.5 by multiple observers, including a team using the Catalina Sky Survey. These observations noted the development of a faint tail and a more defined coma.
- July 2024: The comet brightened to magnitude 11.0, as observed by members of the British Astronomical Association (BAA) Comet Section. The tail was now more prominent, and the comet’s activity was noted to be increasing steadily.
- August 2024: By late August, the comet had reached a magnitude of around 9.5, according to reports from the International Comet Quarterly (ICQ). At this stage, the comet was visible through small telescopes, and its tail was clearly visible in long-exposure images.
These recent observations indicate that Comet C/2023 A3 is on track to become a bright and easily visible object as it approaches its closest point to Earth and perihelion in October 2024.
Observing Opportunities
Comet C/2023 A3 will offer several opportunities for observation in the coming months. Here’s a detailed guide to when and where to look for this exciting celestial object.
Constellations and Viewing Times
The comet will move through several constellations as it approaches perihelion and makes its closest approach to Earth. Here’s a breakdown of its expected path:
- September 2024: The comet will be in the constellation Hydra, visible in the pre-dawn sky. By the end of the month, it will begin moving into Virgo.
- October 2024: As it brightens significantly, the comet will pass through Virgo and into Libra. This will be the best time to observe it as it nears its closest approach to Earth and perihelion. Look for it in Libra during the first half of the month.
- November 2024: After perihelion, the comet will continue to be visible, moving through Ophiuchus and Serpens. Although it will begin to fade, it will still be a prominent object in the evening sky.
Closest Approach and Perihelion
- Closest Approach to Earth: October 12, 2024
On this date, Comet C/2023 A3 will make its closest approach to Earth at a distance of about 0.39 AU (approximately 58 million kilometers or 36 million miles). At this point, the comet is expected to be at or near its brightest, with estimates ranging from magnitude 0 to -1. This will be an excellent opportunity to observe the comet with the naked eye, binoculars, or a telescope. - Perihelion Date: October 13, 2024
The comet will reach perihelion, its closest point to the Sun, on October 13, 2024. At this time, it will be just 0.39 AU (about 58 million kilometers or 36 million miles) from the Sun. While the comet will be at its maximum brightness, it will be very close to the Sun in the sky, making it difficult to observe without proper precautions. The days immediately before and after perihelion, when the comet is still relatively close to Earth and not too close to the Sun, will likely offer the best views.
Predicted Brightness
Comet C/2023 A3 was predicted to reach a peak brightness of magnitude 0 to -1, potentially making it visible to the naked eye. The exact brightness will depend on factors such as the comet’s outgassing activity and the effects of solar heating as it approaches the Sun.
Is comet C/2023 A3 disintegrating?
Comet C/2023 A3 (Tsuchinshan-ATLAS) has sparked significant interest, but recent observations have led to conflicting opinions about its fate. Some astronomers believe the comet is showing signs of fragmentation, while others argue it remains intact.
Concerns About Disintegration: The most prominent voice suggesting that the comet might disintegrate is Dr. Zdenek Sekanina, who published a detailed analysis predicting that Comet Tsuchinshan-ATLAS is unlikely to survive its journey toward perihelion. Sekanina’s findings indicate that the comet’s brightness and dust production have decreased in a pattern consistent with a nucleus breaking apart. This, combined with its Oort Cloud origin and a low synoptic index, suggests that it may disintegrate before reaching perihelion, which occurs at a distance of 0.391 AU from the Sun (around 58.5 million kilometers) on September 27, 2024. The comet is expected to face temperatures exceeding 1,000°F (1,600°C) as it nears the Sun, increasing the likelihood of disintegration.
Opposing Views: However, not all astronomers agree with this bleak outlook. Some, including Nick James of the British Astronomical Association and Dr. Clay Sherrod of the Arkansas Sky Observatories, have observed the comet and found no definitive evidence of fragmentation. They argue that the comet’s behavior, including its ion tail appearance and overall stability, suggests it could still survive and possibly provide a bright display later in 2024.
As of now, the comet has brightened to around 10th magnitude, making it visible through mid-sized telescopes. Despite the warnings of possible disintegration, amateur astronomers and professionals alike continue to monitor its progress closely. The coming weeks and months will be crucial in determining whether Comet Tsuchinshan-ATLAS will remain intact or meet its end before offering the spectacle many hope to witness.
Brightest comet since ISON ?
Comet C/2023 A3 (Tsuchinshan-ATLAS) was shaping up to be one of the most exciting celestial events of 2024. With its potential to become a bright, naked-eye object, this would offer a rare opportunity for both amateur and professional astronomers to witness a comet of this magnitude. If this comet does survive and delivers its predicted peak brightness of between magnitude 0 and -1, this will trump every bright comet observed on Earth since comet C/2012 S1 ISON back in 2013 which famously disintegrated on its journey around the Sun.
The only other comet in recent years that came close to this brightness was Comet C/2020 F3 (NEOWISE) in 2020 which peaked at magnitude +1.0.
Either way, mark your calendars for late September to early October 2024 and prepare your binoculars or telescopes to catch this cosmic visitor as it makes its close approach to Earth and perihelion. Happy observing!