Comets originate from the not–so distant Kuiper belt beyond Neptune. They are very small solar bodies made of ice and dust and orbit around the sun. Some comets have a very low albedo. Albedo means the ability to reflect light from the sun. Comet Bus is a comet with low albedo. In other words, Comet Bus is a faint comet with a short orbital period. This characteristic makes it belong to the Encke–type of comet. It is the 87th short–period comet of Jupiter family. Let us learn in detail about this comet.
Astronomer S J Bus (California Institute of Technology, Pasadena, USA) discovered this comet during a routine survey for minor planets. It was discovered on a plate exposed with the 122 cm UK Schmidt telescope on 2nd March, 1981. The confirmation plate was obtained on 3rd March by K S Russell (Siding Spring Observatory, New South Wales, Australia).
Observations about comet 87P/ Bus include:
- On its discovery, this comet appeared centrally condensed.
- It had a faint tail extending about 20 inches towards north–west.
- Comet Bus was observed having a low albedo, which made it appear faint.
- It showed characteristics of Encke–type of comets namely low albedo, short orbit.etc.
- The comet displayed a condensed head and a tail that extended toward north–west for nearly 20 arc seconds.
On its discovery in March 1981, the image of the comet 87P/ Bus revealed a magnitude of about 17.5. Prior to its discovery images of 9th and 13th February, 1981, it revealed a magnitude of 19.5–20 and 20 respectively.
The perihelion distance (nearest to the sun) of comet 87P/ Bus was calculated at 2.1 AU while its aphelion distance (far from the sun) was about 4.7 AU.
The orbital period of comet 87P/ Bus was noted at around 6.5 years.
The perihelion date of comet 87P/Bus was on 7th July, 2007 and 13th December, 2013. It is expected to pass perihelion or reappear around July 2020.
