Comet C/2023 A3

Don’t look now, but comet C/2023 A3 might just be coming our way. Just recently this comet, also known as Tsuchinshan-ATLAS, was seen close to the Sun. It will reach perihelion – its closest approach to the Sun – on September 27.

There is a chance – a chance – that it might be visible to the naked eye as it travels around the Sun in very late September (east to southeast just before sunrise) and back out toward the Earth in mid to late October (west to southwest just after sunset). See Brian Ventrudo’s article (Cosmic Pursuits) for charts showing the comet’s location. We will update this article with more information as it becomes available (and hopefully a few images).

Comets are objects left over after the formation of the Solar System and consist of frozen gas, dust, rock, and ice. Their nucleus might be a mile to several miles in diameter. Comets heat up as they get close to the Sun and develop a planet sized ”coma” of gases. Pressure from the Sun’s light and the solar wind also produces two tails, which extend for millions of miles.

• One is the ion tail, which is created by the solar wind, composed of gases, is usually blue in color, and points away from the Sun.
• The other is the dust tail, which is illuminated by the Sun’s light and curves back toward the orbit of the comet.

Below are images of comet C/2020 F3 (NEOWISE) taken by two of our members (Dave Morgan and Joe Haberthier) a few years ago.

Just to be clear, comets don’t always behave as we’d like them to. There is the old saying: “Comets are like cats, they have tails and go where they want.”