Comet Leonard made its closest approach to the Sun, known as perihelion, on January 3, 2022, and is now moving farther away from the Sun. It not only dimmed but also lost its two most important parts, the nucleus and the head. The remaining fragment of the comet can be observed in the morning sky from the Southern Hemisphere.
Comet Leonard captured in an image taken on December 28, 2021. Photo by Michael Mattiazzo.
Researcher Gregory Leonard from the Catalina Sky Survey, located in Tucson, Arizona, discovered the comet on January 3, 2021, when it was still far from perihelion. Leonard gradually passed through Earth’s orbit around the Sun and then Venus’ orbit. Initial observations indicated that comet Leonard was bright enough to be seen with the naked eye. By the end of 2021, the comet was closest to Earth.
A comet typically heats up as it approaches the Sun. Its nucleus, which is only a few kilometers wide, warms up, releasing material that evaporates from its surface as gas and dust. The material rising from the nucleus forms an atmosphere called the comet’s head.
By the end of November of last year, comet Leonard became brighter. As it approached perihelion on January 3, 2022, its brightness started fluctuating every 3-5 days. The comet’s tail displayed a complex structure, possibly due to debris breaking away from the nucleus. At this point, astronomers found it challenging to observe the comet. Nevertheless, they continued tracking its fading presence.
On February 23, 2022, researcher Martin Masek captured an image of the comet, noting the absence of a distinct nucleus in the center. Other observers confirmed that comet Leonard had now become a faint streak. It is highly likely that its nucleus, measuring about 1.6 km in diameter, has either fragmented or vaporized.