19P/Borrelly

Discovery

Comet 19P/Borrelly, a periodic comet discovered by French astronomer Alphonse Borrelly on December 28, 1904, follows an orbit around the Sun with a relatively short periodicity of approximately 6.88 years. Its orbital trajectory spans from beyond Jupiter's orbit at its farthest point to just inside Earth's orbit during its closest approach to the Sun (perihelion).

Physical Characteristics

The nucleus of Comet Borrelly is estimated to be about 8 kilometers (5 miles) in diameter. Comets, in general, are composed primarily of ice, dust, rocky materials, and organic compounds. As Comet Borrelly approaches the Sun, solar radiation causes the ice to sublimate, releasing gas and dust that create the characteristic coma (a cloud of gas and dust surrounding the nucleus) and tails extending millions of kilometers through space.

Satellite

A significant event involving Comet 19P/Borrelly was the encounter with NASA's Deep Space 1 (DS1) spacecraft in 2001. DS1 was on a mission to test ion propulsion and new technologies in space. During its close flyby on September 22, 2001, DS1 passed within approximately 2,200 kilometers (1,400 miles) of the comet's nucleus. This encounter allowed DS1 to capture high-resolution images and collect scientific data about the comet's nucleus and coma.

Surface

The data obtained by DS1 during its encounter with Comet Borrelly provided valuable scientific insights. It revealed a heavily cratered surface on the nucleus and detected various gases, such as water vapor, carbon dioxide, and carbon monoxide, emanating from the comet.

Observations

Subsequent observations of Comet 19P/Borrelly have been conducted from Earth during its periodic appearances. These observations continue to provide astronomers with opportunities to study its activity, monitor any changes in its characteristics over time, and deepen our understanding of cometary behavior within the solar system.