A hyperbolic asteroid is any sort of

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. ...

or non-

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...

ary astronomical object observed to have an orbit not bound to the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

and will have an

orbital eccentricity In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values betwee ...

greater than 1 when near

perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

. Unlike hyperbolic comets, they have not been seen out-gassing

light elements Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terah ...

, and therefore have no cometary

coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...

. Most of these objects will only be weakly hyperbolic and will not be of interstellar origin.

Orbit explanation

The planets and most satellites of the solar system revolve in an almost circular motion – called an

elliptical orbit In astrodynamics or celestial mechanics, an elliptic orbit or elliptical orbit is a Kepler orbit with an eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0. In a stricter sense, it ...

– around the Sun or their parent planet, so their orbital eccentricity is generally much closer to 0 than to 1. In mathematics, by definition, an eccentricity (''e'') of 1 characterizes a parabola, and ''e'' > 1, a hyperbola. Some comets are on parabolic and

hyperbolic orbit In astrodynamics or celestial mechanics, a hyperbolic trajectory or hyperbolic orbit is the trajectory of any object around a central body with more than enough speed to escape the central object's gravitational pull. The name derives from the fa ...

s. This means that these hyperbolic asteroids all have an orbital eccentricity greater than 1.

Known hyperbolic asteroids

So far most hyperbolic asteroids discovered have later displayed cometary behavior by either outgassing or demonstrating motion based on

solar radiation pressure Radiation pressure is the mechanical pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field. This includes the momentum of light or electromagnetic radiation of any wavelength that is a ...

. Hyperbolic asteroids are orbital objects with an orbit not bound to the Sun while near perihelion.

ʻOumuamua Oumuamua is the first known interstellar object detected passing through the Solar System. Formally designated 1I/2017 U1, it was discovered by Robert Weryk using the Pan-STARRS telescope at Haleakalā Observatory, Hawaii, on 19 October ...

had the motion of a comet but was never seen outgassing and thus it is listed as a hyperbolic asteroid by the

JPL Small-Body Database The JPL Small-Body Database (SBDB) is an astronomy database about small Solar System bodies. It is maintained by Jet Propulsion Laboratory (JPL) and NASA and provides data for all known asteroids and several comets, including orbital parameters and ...

. * Recent hyperbolic comets that were originally listed as hyperbolic asteroids include C/2017 U7 (A/2017 U7), C/2018 C2 (Lemmon), C/2018 F4 (PANSTARRS), C/2019 O3 (Palomar), and C/2019 G4. * According to astronomer David Jewitt, it is likely that, as the Solar System moves toward the

Lyra Lyra (; Latin for lyre, from Greek ''λύρα'') is a small constellation. It is one of the 48 listed by the 2nd century astronomer Ptolemy, and is one of the modern 88 constellations recognized by the International Astronomical Union. Lyra was ...

constellation, more hyperbolic asteroids will come into the view of astronomers as that is where ‘Oumuamua was observed coming from.

Perturbation

Asteroids can become ejected or in a highly eccentric orbit around the Sun by being ejected by planets like

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

. Just because an orbit solution looks unbound at an

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided by ...

when the object is near

(closest approach to the Sun) does not mean the orbit will be unbound when beyond the planets.

References

External links

MPEC 2019-U194 : A/2019 G4 and A/2019 S4
''

Minor Planet Electronic Circular The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ...

'', 27 October 2019
A/2019 O3
Minor Planet Center
A/2019 G4
Minor Planet Center
A/2017 U7
Minor Planet Center {{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System Hypothetical astronomical objects

Orbit explanation

Known hyperbolic asteroids

Perturbation

See also

References

External links