Amor_asteroids

Amor asteroid

Amor asteroid

Group of near-Earth asteroids

The Amor asteroids are a group of near-Earth asteroids named after the archetype object 1221 Amor /ˈeɪmɔːr/. 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),[1] 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).

Overview of all groups of Near-Earth Objects (NEOs)

Definition

Amor asteroid Eros visited by NEAR Shoemaker in 2000

The orbital characteristics that define an asteroid as being in the Amor group are:[2]

  • The orbital period is greater than one year; i.e., the orbital semi-major axis (a) is greater than 1.0 AU (a > 1.0 AU);
  • The orbit does not cross that of Earth; i.e., the orbital perihelion (q) is greater than Earth's orbital aphelion (q > 1.017 AU);
  • The object is a near-Earth object (NEO); i.e., q < 1.3 AU.

Populations

As of November 2023 there are 12,020 known Amor asteroids. Of those objects, 1275 are numbered and 80 are named.[3]

Outer Earth-grazer asteroids

An outer Earth-grazer asteroid is an asteroid that is normally beyond Earth's orbit, but which can get closer to the Sun than Earth's aphelion (1.0167 AU), and not closer than Earth's perihelion (0.9833 AU); i.e., the asteroid's perihelion is between Earth's perihelion and aphelion. Outer Earth-grazer asteroids are split between Amor and Apollo asteroids. Using the definition of Amor asteroids above, "Earth grazers" that never get closer to the Sun than Earth does (at any point along its orbit) are Amors, whereas those that do are Apollos.

Potentially hazardous asteroids

To be considered a potentially hazardous asteroid (PHA), an object's orbit must, at some point, come within 0.05 AU of Earth's orbit, and the object itself must be sufficiently large/massive to cause significant regional damage if it impacted Earth. Most PHAs are either Aten asteroids or Apollo asteroids (and thus have orbits that cross the orbit of Earth), and as of November 2023 70 Amors are classified as a PHA, the named objects 2061 Anza, 3122 Florence, 3908 Nyx, and 3671 Dionysus.[4]

Lists

For a list of articles about Amor asteroids, see Category:Amor asteroids.

Prominent Amor asteroids

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Named Amor asteroids

This is a non-static list of named Amor asteroids.[5]

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See also

References

  1. [1]
    "Amor asteroid". astronomy encyclopedia. Созвездия.ру. Retrieved 2018-12-26.
  2. [2]
    "NEO Groups". NASA/JPL Near-Earth Object Program Office. Archived from the original on 2002-02-02. Retrieved 2012-06-04.
  3. [3]
    "Small-Body Database Query". Solar System Dynamics - Jet Propulsion Laboratory. NASA - California Institute of Technology. Retrieved 2023-11-13.
  4. [4]
    "List Of The Potentially Hazardous Asteroids (PHAs)". The International Astronomical Union Minor Planet Center. IAU - Minor Planet Center. Retrieved 2023-11-13.
  5. [5]
    "List Of Amor Minor Planets (by designation)". Minor Planet Center. Retrieved 3 March 2017.
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