|Discovered by||K. Reinmuth|
|Discovery site||Heidelberg Obs.|
|Discovery date||24 April 1932|
|NEO · PHA|
|Epoch 29 December 2009 (JD 2455194.5)|
|Uncertainty parameter 0|
|Observation arc||85.32 yr (31162 days)|
|Earliest precovery date||13 December 1930|
|Aphelion||2.2935 AU (343.10 Gm)|
|Perihelion||0.64699 AU (96.788 Gm)|
|1.4702 AU (219.94 Gm)|
|1.78 yr (651.15 d)|
|0° 33m 10.332s / day|
|Earth MOID||0.0257026 AU (3.84505 Gm)|
|Jupiter MOID||3.06837 AU (459.022 Gm)|
|Dimensions||1.5 km (0.93 mi)|
|3.065 h (0.1277 d)|
|Q (Tholen, SMASS)|
B–V = 0.819
U–B = 0.481
1862 Apollo // is a stony asteroid, approximately 1.5 kilometers in diameter, classified as a near-Earth object (NEO). It was discovered by German astronomer Karl Reinmuth at Heidelberg Observatory on 24 April 1932, but lost and not recovered until 1973.
It is the namesake and the first recognized member of the Apollo asteroids, a subgroup of NEOs which are Earth-crossers, that is, they cross the orbit of the Earth when viewed perpendicularly to the ecliptic plane (crossing an orbit is a more general term than actually intersecting it). In addition, since Apollo's orbit is highly eccentric, it crosses the orbits of Venus and Mars and is therefore called a Venus-crosser and Mars-crosser as well.
Although Apollo was the first Apollo asteroid to be discovered, its official IAU-number (1862) is higher than that of some other Apollo asteroids such as 1566 Icarus, due to the fact that it was a lost asteroid for more than 40 years and other bodies were numbered in the meantime. The analysis of its rotation provided observational evidence of the YORP effect.
On November 4, 2005, it was announced that an asteroid moon, or satellite of Apollo, had been detected by radar observations from Arecibo Observatory, Puerto Rico, October 29 – November 2, 2005. The announcement is contained in the International Astronomical Union Circular (IAUC) 8627. The satellite is only 80 m (260 ft) across and orbits Apollo just 3 km (1.9 mi) away from the asteroid itself. From the surface of Apollo, S/2005 (1862) 1 would have an angular diameter of about 2.0835 degrees.[a]
1862 Apollo is a potentially hazardous asteroid (PHA) because its minimum orbit intersection distance (MOID) is less than 0.05 AU and its diameter is greater than 150 meters. Apollo's Earth MOID is 0.0257 AU (3,840,000 km; 2,390,000 mi). Its orbit is well-determined for the next several hundred years. On 17 May 2075 it will pass 0.0083 AU (1,240,000 km; 770,000 mi) from Venus.