103P/Hartley

103P/Hartley, earlier than P / Hartley 2 (and, now even informally ), is a short- period comet with an orbital period of 6.46 years. In 1986 he was discovered by Malcolm Hartley with the UK Schmidt Telescope at Siding Spring Observatory.

Observation and exploration

Observations from the Spitzer Space Telescope in August 2008 showed that the comet's nucleus has a radius of 0.57 ± 0.08 km and an albedo of 0.028. The mass of the comet is estimated to be about 3 ∙ 1011 kg. If the core does not break apart or collides with another object, it is visible in its current mass loss from the Earth for about 100 times (that corresponds to 700 years ).

On 20 October 2010, the comet was flying at a distance of 0.12 AU past the earth, just eight days before his perihelion ( its closest distance to the Sun ) on October 28, 2010. Meanwhile, could the comet with an apparent magnitude of about 5 may be observed in good weather conditions with the naked eye in the constellation Cygnus. It is believed that Hartley 2 after the passage of 2010, the next time on April 20, 2017 passes through the perihelion.

The Deep Impact spacecraft passed 103P/Hartley on November 4, 2010 as part of the EPOXI mission at a distance of 700 km.