C/2014 Q2 (Lovejoy)


C/2014 Q2 is a non-periodic comet discovered on 17 August 2014 by Terry Lovejoy using a Schmidt–Cassegrain telescope. It was discovered as a 15th-magnitude object in the southern constellation of Puppis. It is the fifth comet discovered by Terry Lovejoy.

Observational history

By December 2014, the comet had brightened to roughly magnitude 7.4, making it a small telescope and binoculars target. By mid-December, the comet was visible to the naked eye for experienced observers with dark skies and keen eyesight. On 28–29 December 2014, the comet passed 1/3° from globular cluster Messier 79. In January 2015, it brightened to roughly magnitude 4, and became one of the brightest comets located high in a dark sky since comet C/1995 O1 (Hale–Bopp) in 1997. On 7 January 2015, the comet passed from Earth. It crossed the celestial equator on 9 January 2015, becoming better seen from the Northern Hemisphere. The comet came to perihelion on 30 January 2015, at a distance of from the Sun. At perihelion, its water production rate exceeded 20 metric tons per second.

Orbit

C/2014 Q2 originated from the Oort cloud, but is not a dynamically new comet. Before entering the planetary region, C/2014 Q2 had an orbital period of about years, with an aphelion about from the Sun. After leaving the planetary region, it will have an orbital period of about 8,000 years, with aphelion of about 800 AU.

Physical characteristics

Nucleus size and rotation

The nucleus of Comet Lovejoy was estimated to be in radius, with a rotation period that is completed once every hours.

Chemical composition

The comet was observed to release 21 different organic molecules in gas, including ethanol and glycolaldehyde, a simple sugar. The presence of organic molecules suggests that they are preserved materials synthesized in the outskirts of the solar nebula or at earlier stages of the Solar System formation. The observed gas production rate from the comet was relatively high, estimated to be approximately 5 molecules/sec, which caused the density of ionized water vapor to be effectively constant throughout its inner coma.
Its blue-green glow is the result of organic molecules and water released by the comet fluorescing under the intense UV and optical light of the Sun as it passes through space.