2006 RH120
Encyclopedia
2006 RH120 is a tiny near-Earth asteroid
with a diameter of about five metres, which ordinarily orbits the Sun but makes close approaches to the Earth–Moon system every twenty years or so. Occasionally the object temporarily enters Earth
orbit through temporary satellite capture (TSC). During a temporary satellite capture, the meteoroid may be Earth's only other natural satellite other than the Moon
. Though Alan W. Harris of the Space Science Institute
comments, "Claiming some bit of fluff in a temporary looping orbit to be a ‘satellite,’ with all the baggage that term carries, is mere hype". It most recently was in Earth orbit from September 2006 to June 2007. Until given a minor planet designation on February 18, 2008, the object was known as 6R10DB9, an internal identification number assigned by the Catalina Sky Survey
.
Some controversy existed regarding the origin of the object. Upon discovery, it was not given a formal name since its size, orbit and spectrum – consistent with the white titanium oxide paint used on Saturn V rockets – suggested it might have been an artificial object. A precedent for this exists in J002E3
, currently thought to be the third stage Saturn S-IVB
booster from Apollo 12
, in an almost identical orbit.
. "6R10DB9" was the Catalina Sky Survey's own discovery designation for this object, which usually would only be used on the MPC
's NEO
Confirmation Page (NEOCP) until an IAU
designation was applied, if the object was classified as a minor object. It was added on September 14 to the NEOCP and subsequently removed with the explanation that it "was not a minor planet
." Preliminary orbital calculations indicated it was captured by Earth's gravity from solar orbit of a period of about 11 months, which is similar to that of many spent rocket boosters dating to the Apollo program of the 1960s and early 1970s.
Later analysis shows the NEO is small enough that solar-radiation pressure
is perturbing
its motion perceptibly. However, Paul Chodas in JPL's Solar System Dynamics Group suspects that the perturbations are consistent with expectations for a rocky object but not with old flight hardware. One hypothesis is that the object is a piece of lunar rock ejected by an impact. On February 18, 2008, the object was given a minor planet designation.
The object made four Earth orbits before being ejected after the June 2007 perigee. At that perigee, it dipped inside the Moon's orbit to a distance of 276845 kilometres (172,023.9 mi).
at closest, with an apparent magnitude
of 18.5–19.0.
Astronomer
s at JPL Goldstone
in California
, USA made radar
astrometry
measurements on June 12, 14 and 17, 2007.
The object is now in solar orbit. By 2017, this object will likely be 2 AU
from the Earth on the other side of the Sun. Systematic residuals in the positions of the object probably indicate that the model used to determine solar radiation pressure may be too simple to adequately describe its motion over a long period of time. The next predicted near-Earth encounter is in 2028.
Near-Earth object
A near-Earth object is a Solar System object whose orbit brings it into close proximity with the Earth. All NEOs have a perihelion distance less than 1.3 AU. They include a few thousand near-Earth asteroids , near-Earth comets, a number of solar-orbiting spacecraft, and meteoroids large enough to...
with a diameter of about five metres, which ordinarily orbits the Sun but makes close approaches to the Earth–Moon system every twenty years or so. Occasionally the object temporarily enters Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
orbit through temporary satellite capture (TSC). During a temporary satellite capture, the meteoroid may be Earth's only other natural satellite other than the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
. Though Alan W. Harris of the Space Science Institute
Space Science Institute
The Space Science Institute in Boulder, Colorado, is a nonprofit, public benefit corporation formed in 1992. Its purpose is to create and maintain an environment where scientific research and education programs can flourish in an integrated fashion....
comments, "Claiming some bit of fluff in a temporary looping orbit to be a ‘satellite,’ with all the baggage that term carries, is mere hype". It most recently was in Earth orbit from September 2006 to June 2007. Until given a minor planet designation on February 18, 2008, the object was known as 6R10DB9, an internal identification number assigned by the Catalina Sky Survey
Catalina Sky Survey
Catalina Sky Survey is a project to discover comets and asteroids, and to search for Near-Earth objects. More specifically, to search for potentially hazardous asteroids , that may pose a threat of impact.-Mission:...
.
Some controversy existed regarding the origin of the object. Upon discovery, it was not given a formal name since its size, orbit and spectrum – consistent with the white titanium oxide paint used on Saturn V rockets – suggested it might have been an artificial object. A precedent for this exists in J002E3
J002E3
J002E3 is the designation given to a supposed asteroid discovered by amateur astronomer Bill Yeung on September 3, 2002. Further examination revealed the object was not a rock asteroid but instead the S-IVB third stage of the Apollo 12 Saturn V rocket .When it was first discovered it was quickly...
, currently thought to be the third stage Saturn S-IVB
S-IVB
The S-IVB was built by the Douglas Aircraft Company and served as the third stage on the Saturn V and second stage on the Saturn IB. It had one J-2 engine...
booster from Apollo 12
Apollo 12
Apollo 12 was the sixth manned flight in the American Apollo program and the second to land on the Moon . It was launched on November 14, 1969 from the Kennedy Space Center, Florida, four months after Apollo 11. Mission commander Charles "Pete" Conrad and Lunar Module Pilot Alan L...
, in an almost identical orbit.
History
2006 RH120 was discovered on 14 September 2006 by the 27 inches (685.8 mm) Schmidt camera of the Catalina Sky Survey in ArizonaArizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
. "6R10DB9" was the Catalina Sky Survey's own discovery designation for this object, which usually would only be used on the MPC
Minor Planet Center
The Minor Planet Center operates at the Smithsonian Astrophysical Observatory , which is part of the Center for Astrophysics along with the Harvard College Observatory ....
's NEO
Near-Earth object
A near-Earth object is a Solar System object whose orbit brings it into close proximity with the Earth. All NEOs have a perihelion distance less than 1.3 AU. They include a few thousand near-Earth asteroids , near-Earth comets, a number of solar-orbiting spacecraft, and meteoroids large enough to...
Confirmation Page (NEOCP) until an IAU
International Astronomical Union
The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...
designation was applied, if the object was classified as a minor object. It was added on September 14 to the NEOCP and subsequently removed with the explanation that it "was not a minor planet
Minor planet
An asteroid group or minor-planet group is a population of minor planets that have a share broadly similar orbits. Members are generally unrelated to each other, unlike in an asteroid family, which often results from the break-up of a single asteroid...
." Preliminary orbital calculations indicated it was captured by Earth's gravity from solar orbit of a period of about 11 months, which is similar to that of many spent rocket boosters dating to the Apollo program of the 1960s and early 1970s.
Later analysis shows the NEO is small enough that solar-radiation pressure
Radiation pressure
Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. If absorbed, the pressure is the power flux density divided by the speed of light...
is perturbing
Perturbation (astronomy)
Perturbation is a term used in astronomy in connection with descriptions of the complex motion of a massive body which is subject to appreciable gravitational effects from more than one other massive body....
its motion perceptibly. However, Paul Chodas in JPL's Solar System Dynamics Group suspects that the perturbations are consistent with expectations for a rocky object but not with old flight hardware. One hypothesis is that the object is a piece of lunar rock ejected by an impact. On February 18, 2008, the object was given a minor planet designation.
The object made four Earth orbits before being ejected after the June 2007 perigee. At that perigee, it dipped inside the Moon's orbit to a distance of 276845 kilometres (172,023.9 mi).
June 14, 2007 Perigee
On June 14, 2007, 2006 RH120 made its fourth and last perigee of the most recent Earth encounter. It was 0.7 lunar distancesLunar distance (astronomy)
In astronomy, a lunar distance is a measurement of the distance from the Earth to the Moon. The average distance from Earth to the Moon is 384,400 kilometers...
at closest, with an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
of 18.5–19.0.
Astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
s at JPL Goldstone
Goldstone Deep Space Communications Complex
The Goldstone Deep Space Communications Complex — commonly called the Goldstone Observatory — is located in California's Mojave Desert. Operated by ITT Corporation for the Jet Propulsion Laboratory, its main purpose is to track and communicate with space missions. It includes the Pioneer...
in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, USA made radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
astrometry
Astrometry
Astrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
measurements on June 12, 14 and 17, 2007.
The object is now in solar orbit. By 2017, this object will likely be 2 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
from the Earth on the other side of the Sun. Systematic residuals in the positions of the object probably indicate that the model used to determine solar radiation pressure may be too simple to adequately describe its motion over a long period of time. The next predicted near-Earth encounter is in 2028.
See also
- 6Q0B44E6Q0B44E6Q0B44E, sometimes abbreviated to B44E, is a small object, probably an item of space debris, currently orbiting the Earth outside the orbit of the Moon....
– Another small Earth satellite, probably artificial - 3753 Cruithne3753 Cruithne3753 Cruithne is an asteroid in orbit around the Sun in approximate 1:1 orbital resonance with the Earth. It is a periodic inclusion planetoid orbiting the Sun in an apparent horseshoe orbit. It has been incorrectly called "Earth's second moon", but it is only a quasi-satellite. Cruithne never...
– horseshoeHorseshoe orbitA horseshoe orbit is a type of co-orbital motion of a small orbiting body relative to a larger orbiting body . The orbital period of the smaller body is very nearly the same as for the larger body, and its path appears to have a horseshoe shape in a rotating reference frame as viewed from the...
companion of the Earth – horseshoe companion of the Earth – horseshoe companion of the Earth - Natural satelliteNatural satelliteA natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....