Biela's Comet

3D/Biela

Biela's Comet in February 1846, soon after it split into two pieces.
Discovery
Discovered by	Wilhelm von Biela
Discovery date	February 27, 1826
Designations
Alternative designations	1772; 1806 I; 1832 III; 1846 II; 1852 III; 1826 D1
Orbital characteristics
Epoch	September 29, 1852
Aphelion	6.190 AU
Perihelion	0.8606 AU
Semi-major axis	3.5253 AU
Eccentricity	0.7559
Orbital period	6.619 a
Inclination	12.550°
Last perihelion	September 24, 1852
Next perihelion	Lost

Biela's Comet or Comet Biela (official designation: 3D/Biela) was a periodic comet first recorded in 1772 and identified as periodic in 1826 by Wilhelm von Biela. Subsequently, it was observed to disintegrate and has not been seen since 1852, although remnants survived for some time as a meteor shower.

Discovery

The comet was first recorded in 1772 by Charles Messier. It was also recorded in 1805 by Jean-Louis Pons, but was not recognized as the same object. It was Wilhelm von Biela who observed it during its 1826 perihelion approach (on February 27) and calculated its orbit, discovering it to be periodic with a period of 6.6 years. It was only the third comet (at the time) known to be periodic, after the famous comets Halley and Encke.

Disintegration

In its 1846 appearance, the comet was observed to have broken up into two pieces. It was observed again in 1852 with the two parts being 1.5 million miles apart. Neither part could be found on their predicted periodic returns in 1859, 1865, and 1872. However, on November 27, 1872, a brilliant meteor shower (3,000 per hour) was observed radiating from the part of the sky where the comet had been expected to cross in September 1872. This was the date when Earth intersected the comet's trajectory. These meteors became known as the Andromedids or "Bielids" and it seems apparent that they indicated the death of the comet. The meteors were seen again on subsequent occasions for the rest of the 19th century, but have now faded away.

Comet 207P/NEAT has been proposed as a fragment of Biela since it has a similar orbit.

Meteoric impacts

Biela has sometimes been proposed as the source of meteoric impacts on Earth.

A highly speculative theory links together several major fires that occurred in America during 1871, including the Great Chicago Fire and the Peshtigo Fire, claiming that they were caused by fragments of Biela's Comet striking the Earth. The theory was first proposed in 1883 and was revived in 2004. The theory is very controversial.

On November 27 1885, an iron meteorite fell in northern Mexico, at the same time as a 15,000 per hour outburst of the Andromedid meteor shower. The Mazapil meteorite has sometimes been attributed to the comet, but this idea has been out of favor since the 1950s as the processes of differentiation required to produce an iron body are not believed to occur in comets.

External links

• 3D at Gary W. Kronk's cometography
• The Mazapil meteorite: From paradigm to periphery
• Comet 3D/Biela orbital simulation from JPL (Java)
• Comet P/2001 J1 (NEAT) orbital simulation from JPL (Java)