1221 Amor is an

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

and

near-Earth object A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...

on an eccentric orbit, approximately in diameter. It is the namesake of the Amor asteroids, the second-largest subgroup of near-Earth objects. It was discovered by Eugène Delporte at the

Uccle Observatory The Royal Observatory of Belgium (; ; ) has been situated in the Uccle municipality of Brussels since 1890. It is part of the institutions of the Belgian Federal Science Policy Office (BELSPO). The Royal Observatory was first established in Sa ...

in 1932, the first time that an asteroid was seen to approach Earth so closely. The assumed

S-type asteroid S-type (stony-type or silicaceous-type) asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are ...

is one of few low-numbered asteroids for which no

rotation period In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...

has been determined. It was assigned the provisional designation ' and named for

Cupid In classical mythology, Cupid ( , meaning "passionate desire") is the god of desire, erotic love, attraction and affection. He is often portrayed as the son of the love goddess Venus and the god of war Mars. He is also known as Amor (Latin: ...

, also known as "Amor" in Latin, the Roman equivalent of the Greek god

Eros Eros (, ; ) is the Greek god of love and sex. The Romans referred to him as Cupid or Amor. In the earliest account, he is a primordial god, while in later accounts he is the child of Aphrodite. He is usually presented as a handsome young ma ...

Discovery

On 12 March 1932, Belgian astronomer Eugène Delporte photographed ''Amor'' at the

Royal Observatory of Belgium The Royal Observatory of Belgium (; ; ) has been situated in the Uccle municipality of Brussels since 1890. It is part of the institutions of the Belgian Federal Science Policy Office (BELSPO). The Royal Observatory was first established in S ...

in Uccle, as it approached Earth to within 16 million kilometers (about 40 times the distance from Earth to the Moon). This was the first time that an asteroid was seen to approach Earth so closely. The body's

observation arc In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...

begins with its official discovery observation on 12 March 1932, when it was observed at the

Uccle Uccle (French language, French, ) or Ukkel (Dutch language, Dutch, ) is one of the List of municipalities of the Brussels-Capital Region, 19 municipalities of the Brussels-Capital Region, Belgium. Located in the southern part of the region, it ...

and

Heidelberg Heidelberg (; ; ) is the List of cities in Baden-Württemberg by population, fifth-largest city in the States of Germany, German state of Baden-Württemberg, and with a population of about 163,000, of which roughly a quarter consists of studen ...

observatories simultaneously.

Orbit and classification

''Amor'' is the namesake of the Amor asteroid, a subgroup of

near-Earth asteroid A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun (perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit aro ...

s that approach the orbit of Earth from beyond, but do not cross it. Next to the Apollo group, the Amors are the second largest group of near-Earth objects with more than 7,000 known members. As with many members of this group, ''Amor'' is also a Mars-crosser, crossing the orbit of the Red Planet at 1.66 AU. It orbits the Sun at a distance of 1.08–2.76 AU once every 2 years and 8 months (971 days;

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the longe ...

of 1.92 AU). Its orbit has a high

eccentricity 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-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.44 and an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 12 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

Close encounters

''Amor'' has an Earth minimum orbital intersection distance of which corresponds to 41.6 lunar distances. In March 1940, it approached Earth to , its closest approach of all close encounters since 1900. Only in March 2129, it will approach Earth at a similar distance of .

Naming

This

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

was named after the

Roman Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of Roman civilization *Epistle to the Romans, shortened to Romans, a letter w ...

god of love,

, also known as Amor in Latin, and the Roman equivalent of the Greek god

. The near-Earth asteroids 433 Eros and 763 Cupido are also named after the god of love. The official naming citation was mentioned in '' The Names of the Minor Planets'' by Paul Herget in 1955 ().

Physical characteristics

''Amor'' is an assumed, stony

Rotation period

As of 2018, no rotational

lightcurve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...

of ''Amor'' has been obtained from photometric observations. The body's

, pole and shape remain unknown.

Diameter and albedo

According to Tom Gehrels publication ''Hazards due to Comets and Asteroids'' from 1994 (pp. 540–543), ''Amor'' measures 1.0 kilometer in diameter and its surface has an

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

of 0.15. The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 0.857 kilometers based on an absolute magnitude of 17.7.

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books * * * {{DEFAULTSORT:Amor 001221 Discoveries by Eugène Joseph Delporte Named minor planets 19320312