Comet is a body close to an asteroid but not made of much rock, but mainly ice.[1] It has been described by some experts as a “dirty snowball” because it contains carbon dioxide, methane, and frozen water mixed with dust and minerals. Most comets have very flattened elliptical orbits, some have apogee much farther than Pluto.

The object was first seen on January 9, 2023 by the Purple Mountain Observatory of the Chinese Academy of Sciences, but on March 1, 2023, the Asteroid Center of the National Astronomical Union. (MPC) recently confirmed it as a comet and named it C/2023 A3 (Tsuchinshan-ATLAS).

Currently, C/2023 A3 lies 7.3 AU (1.090 billion km) from the Sun, further than the distance to Jupiter. However, it is moving towards the Sun and the brightness will increase rapidly. According to the Purple Mountain Observatory, the celestial body will reach perihelion on September 28, 2024. At that time, it was about 0.39 AU (58 million km) from the Sun and visible to the naked eye.

Simulation of the current position and orbit of comet C/2023 A3. Photo: Astro Vanbuitenen

C/2023 A3 has a very long cycle. It comes from the far reaches of the solar system, with its last perihelion about 30,000 years ago. This means that comets must contain large reserves of matter.

All available data indicate that C/2023 A3 is a large object. Although the exact diameter of the core is unknown, the apparent magnitude of C/2023 A3 suggests it is quite large.

Many long-period comets can collapse during transits through perihelion. However, C/2023 A3 will fly past the Sun at a relatively safe distance and have a high chance of survival on approach.

A large comet with an orbital period of up to 30,000 years is moving towards the Sun and is expected to reach perihelion in September 2024.

According to NPR, a comet is a collection of solidified gas, rock and dust. However, as they get closer to the Sun and warm up, they transform into cosmic objects that spew gas and dust, resulting in their distinctive appearance of a glowing core and a long, flame-like tail trail. Comets typically produce two types of tails, one mainly composed of gas and the other mostly formed from dust. The dust tail is more visible than the gas tail because dust reflects sunlight well. The gas tail is burned by the Sun’s ultraviolet radiation, causing it to glow similar to phosphorescence.

The green color of comets is not uncommon and is usually the result of the decay of a reactive molecule called dicarbonate – which consists of two carbon atoms linked together by double bonds.

Sao chổi NEOWISE. Ảnh: Juan Carlos Casado

According to the MPC, C/2023 A3’s maximum luminosity in the sky could reach 0 stellar luminosity, meaning it would be six times brighter than the famous comet NEOWISE, observed in the summer of 2020, and 100 times brighter than the recent comet ZTF. The best place to observe C/2023 A3 is in the Northern Hemisphere.

According to VACA, currently C/2023 A3 is located in the area between Saturn and Jupiter. It is moving at about 290,000 km/h and is estimated to come closest to Earth on October 23, 2024. According to astronomers’ orbital calculations, this comet moves around the sun every 80,660 years.

According to Earthsky, it will reach perihelion (the point closest to the sun) on September 28, 2024. Of course, this also depends on whether the comet retains its shape or not.

Source: VNEXPRESS