1862 Apollo is a stony
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
, approximately 1.5 kilometers in diameter, classified as a
near-Earth object
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
(NEO). It was discovered by German astronomer
Karl Reinmuth
Karl Wilhelm Reinmuth (4 April 1892 in Heidelberg – 6 May 1979 in Heidelberg) was a German astronomer and a prolific discoverer of 395 minor planets.
Scientific career
From 1912 to 1957, Reinmuth was working as an astronomer at the Lande ...
at
Heidelberg Observatory
Heidelberg (; Palatine German: ') is a city in the German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of students.
...
on 24 April 1932, but lost and not recovered until 1973.
It is the namesake and the first recognized member of the
Apollo asteroid
The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, discovered by German astronomer Karl Reinmuth in the 1930s. They are Earth-crossing asteroids that have an orbital semi-major axis greater than that of the Earth ...
s, 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
Eccentricity or eccentric may refer to:
* Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal"
Mathematics, science and technology Mathematics
* Off-center, in geometry
* Eccentricity (graph theory) of a v ...
, it crosses the orbits of Venus and Mars and is therefore called a
Venus-crosser
A Venus-crosser is an asteroid whose orbit crosses that of Venus. There are 2,809 and
Mars-crosser
A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and .
Many databases, for i ...
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
A minor planet is "lost" when today's observers cannot find it, because its location is too uncertain to target observations. This happens if the orbital elements of a minor planet are not known accurately enough, typically because the observat ...
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 Yorp or YORP may refer to one of the following:
* 54509 YORP, an Earth co-orbital asteroid
*Yarkovsky–O'Keefe–Radzievskii–Paddack effect, a second-order variation on the Yarkovsky effect
*Yorps, friendly one-eyed Martians from the Commander Ke ...
.
It is named after the Greek god
Apollo
Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label= ...
. He is the god of the Sun, child of Zeus and Leto, after which the minor planets
5731 Zeus and
68 Leto
Leto (minor planet designation: 68 Leto) is a large main belt asteroid that is orbiting the Sun with a period of 4.64 years. Its spectral type is S, suggesting a stony, silicate composition. The asteroid was discovered by German astronomer ...
are named.
Satellite
On November 4, 2005, it was announced that an
asteroid moon
A minor-planet moon is an astronomical object that orbits a minor planet as its natural satellite. , there are 457 minor planets known or suspected to have moons. Discoveries of minor-planet moons (and binary objects, in general) are important ...
, or satellite of Apollo, had been detected by radar observations from
Arecibo Observatory
The Arecibo Observatory, also known as the National Astronomy and Ionosphere Center (NAIC) and formerly known as the Arecibo Ionosphere Observatory, is an observatory in Barrio Esperanza, Arecibo, Puerto Rico owned by the US National Science F ...
,
Puerto Rico
Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...
, October 29 – November 2, 2005. The announcement is contained in the
International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
Circular (IAUC) 8627.
The satellite is only across and orbits Apollo just away from the asteroid itself.
From the surface of Apollo, S/2005 (1862) 1 would have an angular diameter of about 2.0835 degrees.
[Calculated from the formula = (206265) ''d'' / ''D'' arcseconds. (see ]Angular diameter
The angular diameter, angular size, apparent diameter, or apparent size is an angular distance describing how large a sphere or circle appears from a given point of view. In the vision sciences, it is called the visual angle, and in optics, it is ...
)
Potentially hazardous object
1862 Apollo is a
potentially hazardous asteroid
A potentially hazardous object (PHO) is a near-Earth object – either an asteroid or a comet – with an orbit that can make close approaches to the Earth and is large enough to cause significant regional damage in the event of impact. They are ...
(PHA) because its
minimum orbit intersection distance
Minimum orbit intersection distance (MOID) is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. It is defined as the distance between the closest points of the osculating orbits of ...
(MOID) is less than 0.05 AU and its diameter is greater than 150 meters. Apollo's Earth MOID is .
Its orbit is well-determined for the next several hundred years. On 17 May 2075 it will pass from
Venus
Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never fa ...
.
See also
*
Lost asteroid
A minor planet is "lost" when today's observers cannot find it, because its location is too uncertain to target observations. This happens if the orbital elements of a minor planet are not known accurately enough, typically because the observat ...
Notes
References
External links
Lightcurve plot of 1862 Apollo Palmer Divide Observatory, ''
B. D. Warner'' (2005)
Asteroids with Satellites Robert Johnston, johnstonsarchive.net
Asteroid Lightcurve Database (LCDB) query form
)
Dictionary of Minor Planet Names Google books
– Observatoire de Genève, Raoul Behrend
*
*
*
{{DEFAULTSORT:Apollo
001862
Discoveries by Karl Wilhelm Reinmuth
Named minor planets
001862
001862
Earth-crosser asteroids
Venus-crosser asteroids
001862
001862
19320424