C/2019 J2 (Palomar)

C/2019 J2 (Palomar) is a long-period comet discovered on May 6, 2019, by the Zwicky Transient Facility (ZTF) at the Palomar Observatory in California. Its discovery was initially made using data acquired from images taken as part of the ZTF survey. The designation "C/" indicates that it is a non-periodic comet, meaning that its orbital period is very long (greater than 200 years) or that it has an open orbit, and will only pass through the inner solar system once.

The "2019 J2" part of the designation indicates the year of discovery (2019) and the half-month and discovery order within that half-month ("J" signifies the second half of May, and "2" indicates it was the second comet discovered in that period). "(Palomar)" is added to the designation to indicate the observatory where the discovery was made, even though the ZTF survey involves a collaboration and data analysis beyond simply the observatory itself.

Due to its long orbital period and the nature of its discovery, C/2019 J2 (Palomar) likely originated from the Oort cloud, a theoretical spherical region surrounding the solar system believed to be the source of many long-period comets. Observations of the comet's trajectory and brightness have been used by astronomers to determine its orbital parameters and estimate its future path through the solar system. These observations also contribute to a better understanding of the composition and distribution of cometary material in the Oort cloud.