(20403) Attenborough

Asteroid (20403) Attenborough
Properties of the orbit ( animation ) Epoch: May 23, 2014 ( JD 2,456,800.5)
Orbit type	Main outer belt asteroid
Asteroid family	Eos family
Major semi-axis	2.9784 AU
eccentricity	0.0866
Perihelion - aphelion	2.7204 AU - 3.2364 AU
Inclination of the orbit plane	11.6446 °
Length of the ascending node	93.3796 °
Argument of the periapsis	329.0970 °
Sidereal period	5.14 a
Mean orbital velocity	17.27 km / s
Physical Properties
Absolute brightness	13.3 mag
history
Explorer	John Broughton
Date of discovery	July 22, 1998
Another name	1998 OW ₁₁
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.

(20403) Attenborough is a major outer belt asteroid discovered on July 22, 1998 by the Australian amateur astronomer John Broughton at the Reedy Creek Observatory ( IAU code 428). The observatory is located in the district of Reedy Creek the city of Gold Coast in Queensland .

The asteroid belongs to the Eos family , a group of asteroids which typically have large semiaxes from 2.95 to 3.1 AU , bounded inward by the Kirkwood gap of the 7: 3 resonance with Jupiter , and orbital inclinations between 8 ° and 12 °. The group is named after the asteroid (221) Eos . The family is believed to have emerged from a collision more than a billion years ago. The timeless (non- osculating ) orbital elements of (20403) Attenborough are almost identical to those of the two smaller ones, assuming the absolute magnitude of 14.3 and 14.5 compared to 13.3, asteroids (35203) 1994 PF ₁₅ and ( 87494) 2000 QC ₁₆₁ .

(20403) Attenborough was named on December 30, 2001 after the brothers David and Richard Attenborough . David Attenborough is a wildlife filmmaker and naturalist , Richard Attenborough was an actor and director .

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