433 Eros

Eros (/ˈɪərɒs/ EER-os; minor planet designation: 433 Eros), provisional designation 1898 DQ, is a stony and elongated asteroid of the Amor group and the first discovered and second-largest near-Earth object with a mean-diameter of approximately 16.8 kilometers. Visited by the NEAR Shoemaker space probe in 1998, it became the first asteroid ever studied from orbit.

The eccentric asteroid was discovered by German astronomer Carl Gustav Witt at the Berlin Urania Observatory on 13 August 1898, and later named after Eros, a god from Greek mythology.[2]

433 Eros
Eros - PIA02923 (color)
Eros [a]
Discovery [1]
Discovered byG. Witt
Discovery siteBerlin Urania Obs.
Discovery date13 August 1898
MPC designation(433) Eros
Named after
Eros (Greek mythology)[2]
1898 DQ · 1956 PC
NEO · Amor (I)[1]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc53.89 yr (19,683 days)
Aphelion1.7825 AU
Perihelion1.1334 AU
1.4579 AU
1.76 yr (643 days)
0° 33m 35.64s / day
Earth MOID0.1505 AU · 58.6 LD
Physical characteristics
Dimensions16.84±0.06 km (mean diameter)[1][3]
34.4 × 11.2 × 11.2 km[1][4]
Mass(6.687±0.003)×1015 kg[3]
Mean density
2.67±0.03 g/cm³[1][3]
5.270 h[1]
S (Tholen), S (SMASS)[1]
B–V = 0.921[1]
U–B = 0.531[1]



Eros was discovered on 13 August 1898, by Carl Gustav Witt at Berlin Urania Observatory and Auguste Charlois at Nice Observatory.[6] Witt was taking a 2-hour exposure of Beta Aquarii to secure astrometric positions of asteroid 185 Eunike.[7]

Later studies

During the opposition of 1900–1901, a worldwide program was launched to make parallax measurements of Eros to determine the solar parallax (or distance to the Sun), with the results published in 1910 by Arthur Hinks of Cambridge.[8] A similar program was then carried out, during a closer approach, in 1930–1931 by Harold Spencer Jones.[9] The value of the Astronomical Unit (roughly the Earth-Sun distance) obtained by this program was considered definitive until 1968, when radar and dynamical parallax methods started producing more precise measurements.

Eros was the first asteroid detected by the Arecibo Observatory's radar system.[10][11]

Eros was one of the first asteroids visited by a spacecraft, the first one orbited, and the first one soft-landed on. NASA spacecraft NEAR Shoemaker entered orbit around Eros in 2000, and landed in 2001.


Eros is a Mars-crosser asteroid, the first known to come within the orbit of Mars. Objects in such an orbit can remain there for only a few hundred million years before the orbit is perturbed by gravitational interactions. Dynamical integrations suggest that Eros may evolve into an Earth-crosser within as short an interval as two million years, and has a roughly 50% chance of doing so over a time scale of 108–109 years.[12] It is a potential Earth impactor,[12] about five times larger than the impactor that created Chicxulub crater and led to the extinction of the dinosaurs.[b]


Eros is named after the Greek god of love, Erōs. It is pronounced /ˈɪərɒs/ EER-os or sometimes /ˈɛrɒs/ ERR-os. The rarely used adjectival form of the name is Erotian /ɪˈroʊʃən/. Eros is also the first masculine name for an asteroid.[13]

NEAR Shoemaker

Animation of NEAR Shoemaker trajectory
Animation of NEAR Shoemaker trajectory from May 31, 1996 to February 12, 2001.
NEAR Shoemaker; 433 Eros; Earth;   253 Mathilde ; Sun;
Animation of NEAR Shoemaker trajectory around 433 Eros
Animation of NEAR Shoemaker's trajectory around 433 Eros from April 1, 2000 to February 12, 2001
   NEAR Shoemaker ·   433 Eros

The NEAR Shoemaker probe visited Eros twice, first with a 1998 flyby, and then by orbiting it in 2000 when it extensively photographed its surface. On February 12, 2001, at the end of its mission, it landed on the asteroid's surface using its maneuvering jets.

Physical characteristics

Surface gravity depends on the distance from a spot on the surface to the center of a body's mass. Eros's surface gravity varies greatly because Eros is not a sphere but an elongated peanut-shaped (or potato- or shoe-shaped) object. The daytime temperature on Eros can reach about 100 °C (373 K) at perihelion. Nighttime measurements fall near −150 °C (123 K). Eros's density is 2.67 g/cm3, about the same as the density of Earth's crust. It rotates once every 5.27 hours.

NEAR scientists have found that most of the larger rocks strewn across Eros were ejected from a single crater in an impact approximately 1 billion years ago.[14] (The crater involved was proposed to be named "Shoemaker", but is not recognized as such by the International Astronomical Union (IAU), and has been formally designated Charlois Regio.) This event may also be responsible for the 40 percent of the Erotian surface that is devoid of craters smaller than 0.5 kilometers across. It was originally thought that the debris thrown up by the collision filled in the smaller craters. An analysis of crater densities over the surface indicates that the areas with lower crater density are within 9 kilometers of the impact point. Some of the lower density areas were found on the opposite side of the asteroid but still within 9 kilometers.[15]

It is theorized that seismic shockwaves propagated through the asteroid, shaking smaller craters into rubble. Since Eros is irregularly shaped, parts of the surface antipodal to the point of impact can be within 9 kilometres of the impact point (measured in a straight line through the asteroid) even though some intervening parts of the surface are more than 9 kilometres away in straight-line distance. A suitable analogy would be the distance from the top centre of a bun to the bottom centre as compared to the distance from the top centre to a point on the bun's circumference: top-to-bottom is a longer distance than top-to-periphery when measured along the surface but shorter than it in direct straight-line terms.[15]

Compression from the same impact is believed to have created the thrust fault Hinks Dorsum.[16]

Data from the Near Earth Asteroid Rendezvous spacecraft collected on Eros in December 1998 suggests that it could contain 20,000 billion kilograms of aluminum and similar amounts of metals that are rare on Earth, such as gold and platinum.[17]

Visibility from Earth

Eros path 2012
Path in sky during opposition 2011/2012

On January 31, 2012, Eros passed Earth at 0.17867 AU (26,729,000 km; 16,608,000 mi),[18][19] about 70 times the distance to the Moon, with a visual magnitude of +8.1.[20] During rare oppositions, every 81 years, such as in 1975 and 2056, Eros can reach a magnitude of +7.0,[5] which is brighter than Neptune and brighter than any main-belt asteroid except 1 Ceres, 4 Vesta and, rarely, 2 Pallas and 7 Iris. Under this condition, the asteroid actually appears to stop, but unlike the normal condition for a body in heliocentric conjunction with Earth, its retrograde motion is very small. For example, in January and February 2137, it moves retrograde only 34 minutes in right ascension.[1]


Eros rotation Dec. 3-4 2000

Animation of the rotation of Eros


View from one end of Eros across the gouge on its side towards the opposite end

433 Eros first look

At 4.8 km (3.0 mi) across, the crater Psyche is Eros's second largest


Regolith of Eros, seen during NEAR's descent; area shown is about 12 meters (40 feet) across

Eros May 7 2013

Orbital diagram of Eros with locations on May 7, 2013

Eros orbit 2018

Orbital diagram of Eros with locations on January 1, 2018

Eros, Vesta and Ceres size comparison

Size comparison of Vesta, Ceres and Eros

PIA02475 Eros' Bland Butterscotch Colors

Six different views of Eros in approximate natural color from NEAR-Shoemaker in February 2000

See also


  1. ^ A composite image of the north polar region, with the craters Psyche above and Himeros below. The long ridge Hinks Dorsum, believed to be a thrust fault, can be seen snaking diagonally between them. The smaller crater in the foreground is Narcissus (Watters, 2011)
  2. ^ Ratio of mean diameters is 16.84 km/~10 km; the volume ratio is approximately 4.8 (cubed value).


  1. ^ a b c d e f g h i j k l m "JPL Small-Body Database Browser: 433 Eros (1898 DQ)" (2017-06-04 last obs.). Jet Propulsion Laboratory. Retrieved 16 August 2017.
  2. ^ a b Schmadel, Lutz D. (2007). "(433) Eros". Dictionary of Minor Planet Names – (433) Eros. Springer Berlin Heidelberg. p. 50. doi:10.1007/978-3-540-29925-7_434. ISBN 978-3-540-00238-3.
  3. ^ a b c Yeomans, D. K.; Antreasian, P. G.; Barriot, J.-P.; Chesley, S. R.; Dunham, D. W.; Farquhar, R. W.; et al. (September 2000). "Radio Science Results During the NEAR-Shoemaker Spacecraft Rendezvous with Eros". Science. 289 (5487): 2085–2088. Bibcode:2000Sci...289.2085Y. doi:10.1126/science.289.5487.2085. ISSN 0036-8075. PMID 11000104. Retrieved 16 August 2017.
  4. ^ Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. Retrieved 2008-12-11.
  5. ^ a b "NEODys (433) Eros Ephemerides for 2137". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-06-27.
  6. ^ Scholl, Hans; Schmadel, Lutz D. (2002). "Discovery Circumstances of the First Near-Earth Asteroid (433) Eros". Acta Historica Astronomiae. 15: 210–220. Bibcode:2002AcHA...15..210S.
  7. ^ Yeomans, Donald K.; Asteroid 433 Eros: The Target Body of the NEAR Mission Archived 2007-09-28 at the Wayback Machine, Jet Propulsion Laboratory/California Institute of Technology.
  8. ^ Hinks, Arthur R. (1909). "Solar Parallax Papers No. 7: The General Solution from the Photographic Right Ascensions of Eros, at the Opposition of 1900". Monthly Notices of the Royal Astronomical Society. 69 (7): 544–67. Bibcode:1909MNRAS..69..544H. doi:10.1093/mnras/69.7.544.
  9. ^ Jones, H. Spencer (1941). "The Solar Parallax and the Mass of the Moon from Observations of Eros at the Opposition of 1931". Mem. Roy. Astron. Soc. 66: 11–66.
  10. ^ Butrica, Andrew J. (1996). To see the unseen: a history of planetary radar astronomy (2nd ed.). Washington, DC: National Aeronautics and Space Administration. p. 224. ISBN 978-0160485787.
  11. ^ "Introduction to Asteroid Radar Astronomy". UCLA. Retrieved 2014-05-19.
  12. ^ a b Michel, Patrick; Farinella, Paolo; Froeschlé, Christiane (1996-04-25). "The orbital evolution of the asteroid Eros and implications for collision with the Earth". Nature. 380 (6576): 689–691. Bibcode:1996Natur.380..689M. doi:10.1038/380689a0. Retrieved 2011-02-12.
  13. ^ 1920-1992., Asimov, Isaac (1988). The asteroids (A Gareth Stevens children's books ed.). Milwaukee: G. Stevens Pub. ISBN 978-1555323783. OCLC 17301161.
  14. ^ Thomas, P. C.; Veverka, J.; Robinson, M. S.; Murchie, S. (2001-09-27). "Shoemaker crater as the source of most ejecta blocks on the asteroid 433 Eros". Nature. 413 (6854): 394–396. Bibcode:2001Natur.413..394T. doi:10.1038/35096513. ISSN 0028-0836. PMID 11574880.
  15. ^ a b Thomas, P. C.; Robinson, M. S. (2005-07-21). "Seismic resurfacing by a single impact on the asteroid 433 Eros". Nature. 436 (7049): 366–369. Bibcode:2005Natur.436..366T. doi:10.1038/nature03855. PMID 16034412.
  16. ^ Watters, T. R.; Thomas, P. C.; Robinson, M. S. (2011). "Thrust faults and the near-surface strength of asteroid 433 Eros". Geophysical Research Letters. 38 (2): L02202. Bibcode:2011GeoRL..38.2202W. doi:10.1029/2010GL045302. ISSN 0094-8276.
  17. ^ "Gold rush in space?". BBC News. Retrieved 13 December 2014.
  18. ^ "JPL Close-Approach Data: 433 Eros (1898 DQ)" (2011-11-13 last obs). Retrieved 2011-11-14.
  19. ^ "NEODyS-2 Close Approaches for (433) Eros". Near Earth Objects - Dynamic Site. Retrieved 2011-11-14.
  20. ^ "AstDys (433) Eros Ephemerides for 2012". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-06-27.

External links

Further reading

  • Clark, C. S.; Clark, P. E (March 13–17, 2006). "Using Boundary-based Mapping Projections to Reveal Patterns in Depositional and Erosional Features on 433 Eros". 37th Annual Lunar and Planetary Science Conference. 37: 1189. Bibcode:2006LPI....37.1189C.
  • Riner, M. A.; et al. (November 2008). "Global survey of color variations on 433 Eros: Implications for regolith processes and asteroid environments". Icarus. 198 (1): 67–76. Bibcode:2008Icar..198...67R. doi:10.1016/j.icarus.2008.07.007.
422 Berolina

Berolina (minor planet designation: 422 Berolina) is a typical Main belt asteroid.

It was discovered by G. Witt on 8 October 1896 in Berlin. It was first of his two asteroid discoveries. The other was the famous asteroid 433 Eros.

Although it has an orbit similar to the Flora family asteroids, it appears to be an unrelated interloper due to not being of the S spectral type (see the PDS asteroid taxonomy data set).

4954 Eric

4954 Eric, provisional designation 1990 SQ is an eccentric, stony asteroid, classified as near-Earth object of the Amor group, approximately 11 kilometers in diameter. It was discovered by American astronomer Brian Roman at Palomar Observatory on 23 September 1990. The asteroid was named after its discoverer's son, Eric Roman.

It is the largest near-Earth asteroid discovered since 3552 Don Quixote in 1983. On 2007 October 11 the asteroid passed 0.2865 AU (42,860,000 km; 26,630,000 mi) from Earth. It currently makes closer approaches to Mars than it does Earth. The asteroid has a rotation period of 12.05 hours.Other large near-Earth asteroids include: 1036 Ganymed (32 km), 3552 Don Quixote (19 km), 433 Eros (17 km), and 1866 Sisyphus (8.5 km).

Amor asteroid

The Amor asteroids are a group of near-Earth asteroids named after the archetype object 1221 Amor. The orbital perihelion of these objects is close to, but greater than, the orbital aphelion of Earth (i.e., the objects do not cross Earth's orbit), with most Amors crossing the orbit of Mars. The Amor asteroid 433 Eros was the first asteroid to be orbited and landed upon by a robotic space probe (NEAR Shoemaker).

Anna Winlock

Anna Winlock (1857-1904) was an American astronomer and human computer, one of the first members of female computer group known as "the Harvard Computers." She made the most complete catalog of stars near the north and south poles of her era. She is also remembered for her calculations and studies of asteroids. In particular, she did calculations on 433 Eros and 475 Ocllo.

Asteroid (film)

Asteroid is a 1997 NBC TV miniseries about the United States government trying to prevent an asteroid from colliding with the Earth.

Captive Universe

Captive Universe is a science fiction novel by American author Harry Harrison, which was first published in 1969.

Carl Gustav Witt

Carl Gustav Witt (October 29, 1866 – January 3, 1946) was a German astronomer and discover of two asteroids who worked at the Berlin Urania Observatory, a popular observatory of the Urania astronomical association of Berlin.He wrote a doctoral thesis under the direction of Julius Bauschinger.

Witt discovered two asteroids, most notably 433 Eros, the first asteroid with a male name, and the first known near-Earth object. His first minor planet discovery was the main-belt asteroid 422 Berolina, that bears the Latin name of his adoptive city.The minor planet 2732 Witt – an A-type asteroid from the main-belt, discovered by Max Wolf at Heidelberg Observatory in 1926 – was named in his memory by American astronomer and MPC's longtime director, Brian G. Marsden. Naming citation was published on 22 September 1983 (M.P.C. 8153).

Dig Allen Space Explorer

Dig Allen Space Explorer is a series of six science-fiction novels (1959–1962) by American author Joseph Greene. Much like Greene's earlier creation, Tom Corbett, Space Cadet, the series chronicles the adventures of a group of intrepid adolescent boys, led by boy hero Digby "Dig" Allen. The setting centers on the asteroid Eros, which is discovered to be an immense alien spacecraft. In every installment, the boys embark upon interplanetary voyages around the Solar System that are set against nefarious schemes from a variety of adversaries.

The Dig Allen Space Explorer series consists of:

The Forgotten Star (1959)

Captives in Space (1960)

Journey to Jupiter (1961)

Trappers of Venus (1961)

Robots of Saturn (1962)

Lost City of Uranus (1962)

Donald B. Campbell

Donald B. Campbell is an Australian-born astronomer and Professor of Astronomy at Cornell University. Prior to joining the Cornell faculty he was Director of the Arecibo Observatory in Puerto Rico for seven years. Campbell's research work is in the general area of planetary studies with a concentration on the radio-wavelength-scattering properties of planets, planetary satellites, and small bodies. His work includes studies of Venus, the Moon, the Galilean satellites of Jupiter, Titan, as well as comets and asteroids. Campbell observed near-Earth asteroid 433 Eros, which was the first asteroid detected by the Arecibo Observatory radar system.

L chondrite

The L type ordinary chondrites are the second most common group of meteorites, accounting for approximately 35% of all those catalogued, and 40% of the ordinary chondrites. The ordinary chondrites are thought to have originated from three parent asteroids, with the fragments making up the H chondrite, L chondrite and LL chondrite groups respectively.

Leviathan Wakes

Leviathan Wakes (2011) is a science fiction novel by James S. A. Corey, the pen name of Daniel Abraham and Ty Franck. It is the first book in the Expanse series, followed by Caliban's War (2012), Abaddon's Gate (2013), Cibola Burn (2014), Nemesis Games (2015), Babylon's Ashes (2016), and Persepolis Rising (2017).

Leviathan Wakes was nominated for the 2012 Hugo Award for Best Novel and the 2012 Locus Award for Best Science Fiction Novel. The novel was adapted for television in 2015 as the first and part of the second season of The Expanse by Syfy.

List of geological features on 433 Eros

This is a list of named geological features on asteroid 433 Eros.

List of missions to minor planets

List of missions to minor planets is a listing of spaceflight missions to minor planets, which are category of astronomical body that excludes planets, moons and comets, but orbit the Sun. Most missions to minor planets have been to asteroids or dwarf planets.

Spacecraft visits to minor planets have mostly been flybys, and have ranged from dedicated missions to incidental flybys and targets of opportunity for spacecraft that have already completed their missions. The first spacecraft to visit an asteroid was Galileo, which flew past 951 Gaspra in October 1991; an incidental encounter while the probe was en route to Jupiter. The first dedicated mission was NEAR Shoemaker, which was launched in February 1996, and entered orbit around 433 Eros in February 2000, having first flown past 253 Mathilde. NEAR was also the first spacecraft to land on an asteroid, surviving what was intended to be an impact with Eros at 20:01 on 12 February 2001 at the planned end of its mission. As a result of its unexpected survival, the spacecraft's mission was extended until 1 March to allow data to be collected from the surface.

Many minor planets are in two rings:

Asteroid belt, between 2-3 AU

Kuiper belt, between 30-60 AU

List of planetary features with Māori names

In the International Astronomical Union's system of unique feature names for topographic and albedo features on planets and moons in the Solar System, many are named in the language of the indigenous Māori people of New Zealand. These names are primarily from Māori mythology.

NEAR Shoemaker

The Near Earth Asteroid Rendezvous – Shoemaker (NEAR Shoemaker), renamed after its 1996 launch in honor of planetary scientist Eugene Shoemaker, was a robotic space probe designed by the Johns Hopkins University Applied Physics Laboratory for NASA to study the near-Earth asteroid Eros from close orbit over a period of a year. The mission succeeded in closing in with the asteroid and orbited it several times, finally terminating by touching down on the asteroid on 12 February 2001.

The primary scientific objective of NEAR was to return data on the bulk properties, composition, mineralogy, morphology, internal mass distribution and magnetic field of Eros. Secondary objectives include studies of regolith properties, interactions with the solar wind, possible current activity as indicated by dust or gas, and the asteroid spin state. This data will be used to help understand the characteristics of asteroids in general, their relationship to meteoroids and comets, and the conditions in the early Solar System. To accomplish these goals, the spacecraft was equipped with an X-ray/gamma-ray spectrometer, a near-infrared imaging spectrograph, a multi-spectral camera fitted with a CCD imaging detector, a laser rangefinder, and a magnetometer. A radio science experiment was also performed using the NEAR tracking system to estimate the gravity field of the asteroid. The total mass of the instruments was 56 kg, and they required 80 W power.

Shoemaker (disambiguation)

A shoemaker is a person making shoes.

Shoemaker may also refer to:

Shoemaker (surname)

NEAR Shoemaker, a NASA mission to study 433 Eros

The Shoemaker (2011 play) a stageplay written by Susan Charlotte

102P/Shoemaker (aka Shoemaker 1) a comet

Shoemaker crater (disambiguation)

Shoemaker crater may refer to:

Shoemaker crater (aka Teague Ring) in Australia

Shoemaker (lunar crater) at the south pole of the Moon

Shoemaker crater (433 Eros), a proposed name for an impact feature on the asteroid Eros, now formally named Charlois Regio

Unowned property

Unowned property refers to tangible, physical things which are capable of being reduced to being property owned by an individual, but are not owned by anyone. Nearly every piece of land on the Earth is property and has a maintainer (owner). The class of objects, "unowned things", are objects which are not yet property; either because it has been agreed by sovereign nations that no one can own them, or because no person, or other entity, has made a claim of ownership.

The most common unowned things are asteroids. The UN's Outer Space Treaty does not address the issue of private ownership of natural objects in space. All asteroids remain unowned things until some person or entity makes a claim of property right to one of them.

In an experimental legal case of first impression, a lawsuit for a declaratory judgment was filed in a United States Federal Court to determine the lawful owner of Asteroid 433 Eros. 433 Eros was claimed as property by Gregory W. Nemitz of Orbital Development. According to the homestead principle, Nemitz argued that he had the right to claim ownership of any celestial body that he made use of; he claimed he had designated Eros a spacecraft parking facility and wished to charge NASA a parking and storage fee of twenty cents per year for its NEAR Shoemaker spacecraft that is permanently stored there. Nemitz's case was dismissed due to lack of standing and an appeal denied.

William Stephen Finsen

William Stephen Finsen (28 July 1905 – 16 May 1979) was a South African astronomer.

He discovered a number of double stars and took many photographs of Mars. He developed the Finsen eyepiece interferometer to measure very close double stars. He was the final director of Union Observatory in South Africa from 1957 until it closed in 1965 (it was renamed Republic Observatory in 1961); he had started there 55 years previous.The asteroid 1794 Finsen is named after him, as is the geological feature Finsen Dorsum on the asteroid 433 Eros.

Minor planets

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