Comet Tsuchinshan–ATLAS
The bright comet of October 2024, with a long tail and a rare antitail pointing towards the Sun.
Key facts
- Designation
- C/2023 A3 (Tsuchinshan–ATLAS)
- Type
- Long-period comet from the Oort cloud
- Orbital period
- very long; it may be leaving the Solar System for good
- Closest to the Sun
- 0.39 AU (about 58 million km)
- Farthest from the Sun
- far beyond the planets
- Tilt of orbit
- about 139° (retrograde)
- Nucleus
- a few kilometres across
- Discovered
- by Purple Mountain Observatory in China on 9 January 2023 and the ATLAS survey in South Africa on 22 February 2023
- Returns
- passed closest to the Sun on 27 September 2024 and closest to Earth on 12 October 2024
Orbit
The comet fell in from the Oort cloud, the vast, distant shell of icy bodies surrounding the Solar System. It passed the Sun on 27 September 2024 at about 58 million km and Earth on 12 October at about 71 million km. The planets' gravity may have given it enough of a push to leave the Solar System forever.
Size and nature
At its peak in early October, when it was almost between Earth and the Sun, its dust scattered sunlight forward towards us and it briefly became very bright, though it was then so near the Sun that spacecraft had the best view. A week later, in the evening sky, it showed a long tail and a thin spike pointing the other way. That antitail was dust lying in the comet's orbital plane, seen edge-on when Earth crossed that plane on 14 October.
History
The Purple Mountain Observatory at Xuyi in China, whose name in Chinese is Tsuchinshan, found it in January 2023. The ATLAS survey, which hunts asteroids, found it independently in February. Earlier pictures showed it already active at a distance beyond Jupiter. Some astronomers feared it would break up near the Sun, but it survived.
Meteor showers and missions
Its orbit does not bring its dust to Earth. The SOHO spacecraft filmed it passing near the Sun, and astronauts photographed it from the International Space Station.
Space missions
- SOHO A solar observatory that has become the greatest comet discoverer in history.
Key dates
| Date | What happened |
|---|---|
| 9 January 2023 | Purple Mountain Observatory discovered Comet Tsuchinshan–ATLAS. |
| 27 September 2024 | Comet Tsuchinshan–ATLAS passed closest to the Sun. |
| 12 October 2024 | Comet Tsuchinshan–ATLAS passed closest to Earth, at about 71 million km. |
Did you know?
Tsuchinshan is the old way of writing Zijinshan, the Purple Mountain.
Forward scattering made it briefly far brighter than its size alone would suggest.
Its antitail was more than 10 degrees long in photographs.