103P/Hartley: the story on HearLore

Earth Approaches

The comet passed within 5 million kilometers of Earth on the 20th of October 2010. This event occurred just eight days before the object reached perihelion on the 28th of October 2010. Observers in northern latitudes could see the comet around midnight during early November without moonlight interference. It shone with an apparent magnitude of about 5 making it dimly visible to the naked eye. A second close approach happened on the 26th of September 2023 when the comet traveled 18.3 astronomical units from our planet. Dust trails from recent returns move in and out of Earth's orbit but no meteor shower is currently known. Scientists predict the 1979-dust trail will hit Earth in 2062 and again in 2068.

Physical Characteristics

Spitzer Space Telescope observations in August 2008 revealed a nucleus radius of roughly 500 meters. The surface reflects only 0.028 of incoming light indicating a very dark albedo. Radar data from Arecibo Observatory showed the nucleus rotates over an 18-hour period while remaining highly elongated. Mission scientists described the shape as resembling a cross between a bowling pin and a pickle. Estimates place the total mass at approximately 4 billion kilograms. The comet should survive up to another 100 apparitions or about 700 years barring catastrophic breakup. Herschel Space Observatory detected vaporized water signatures in 2011 showing half the heavy water found in other comets.

Who discovered 103P/Hartley and when was it found?

Malcolm Hartley spotted 103P/Hartley in 1986 using the Schmidt Telescope Unit at Siding Spring Observatory in Australia. This small periodic comet now bears his name as 103P/Hartley.

When did 103P/Hartley pass closest to Earth during its recent history?

The comet passed within 5 million kilometers of Earth on the 20th of October 2010. A second close approach happened on the 26th of September 2023 when the comet traveled 18.3 astronomical units from our planet.

What is the physical shape and size of the nucleus of 103P/Hartley?

Radar data from Arecibo Observatory showed the nucleus rotates over an 18-hour period while remaining highly elongated with a radius of roughly 500 meters. The flyby captured images showing a peanut-shaped body stretching 2 kilometers long that resembles a cross between a bowling pin and a pickle.

How far does 103P/Hartley orbit around the Sun and how often does it return?

It follows an elliptical path around the Sun that repeats every 6.48 years. Astronomers classify this object as a Jupiter-family comet due to its orbital characteristics.

Why does 103P/Hartley exhibit unusual activity compared to other comets?

This encounter marked the first time carbon dioxide sublimation powered comet activity near the Sun. Carbon dioxide gas drives most ejected material according to EPOXI findings.

103P/Hartley.

Earth Approaches

Physical Characteristics

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