42P12

42P12, also known as Comet 42P/Neujmin 2, is a periodic comet in the Solar System with an orbital period of approximately 6.04 years. It was discovered on August 28, 1929, by the Soviet astronomer Grigory Neujmin at the Simeiz Observatory on the Crimean peninsula. The comet is named after its discoverer and the number "2" indicates that it was the second comet discovered by Neujmin.

42P12 has a relatively short orbital period compared to other comets, which means it completes one orbit around the Sun more frequently. Its orbit is inclined at an angle of about 11.7 degrees to the ecliptic plane, and it has an eccentricity of 0.53, indicating a moderately elliptical orbit. The comet's perihelion, the point in its orbit closest to the Sun, occurs at a distance of about 1.04 astronomical units (AU), while its aphelion, the farthest point, is at approximately 4.61 AU.

The nucleus of 42P12 is estimated to be about 1.6 kilometers in diameter. The comet is known to exhibit a coma, a fuzzy atmosphere surrounding the nucleus, and a tail when it approaches the Sun. The coma and tail are primarily composed of gas and dust ejected from the nucleus as it heats up due to solar radiation.

42P12 is classified as a Jupiter-family comet, meaning its orbit is influenced by the gravitational pull of Jupiter. Over time, interactions with Jupiter can alter the comet's orbit, potentially leading to its eventual ejection from the Solar System or a collision with the Sun or a planet.

The next perihelion passage of 42P12 is expected to occur on February 17, 2024. Astronomers and amateur stargazers may observe the comet during this time, as it approaches the Sun and develops its coma and tail.