Vesta family
Encyclopedia
The Vesta or Vestian family of asteroids
is a large and prominent grouping of mostly V-type
asteroid
s in the inner asteroid belt
in the vicinity of 4 Vesta
. Approximately 6% of main-belt asteroids belong to this family.
, the second-most-massive of all asteroids (mean diameter of 530 km), and many small asteroids below 10 km diameter. The brightest of these, 1929 Kollaa
and 2045 Peking
, have an absolute magnitude
of 12.2, which would give them a radius of about 7.5 km assuming the same high albedo as 4 Vesta
.
The family originated from an impact on asteroid 4 Vesta
, with the giant south-polar crater the likely impact site. The family are thought to be the source of the HED meteorite
s.
The Vesta family also includes a few J-type asteroid
s (related to the V-type
), which are thought to have come from the deeper layers of Vesta's crust, and are similar to the diogenite
meteorites
A HCM numerical analysis by (Zappala 1995) determined a large group of 'core' family members, whose proper orbital elements
lie in the approximate ranges
! !! ap
!! ep
!! ip
>
min
2.26 AU
0.075
5.6°
max
2.48 AU
0.122
7.9°
This gives the approximate boundaries of the family. At the present epoch
, the range of osculating
orbital elements
of these core members is
The Zappala 1995 analysis found 235 core members. A search of a recent proper-element database (AstDys) for 96944 minor planet
s in 2005 yielded 6051 objects (about 6% of the total) lying within the Vesta-family region as per the first table above.
or J
spectral class, but have similar orbital elements by coincidence. These include 306 Unitas
, 442 Eichsfeldia
, 1697 Koskenniemi
, 1781 Van Biesbroeck
, 2024 McLaughlin
, 2029 Binomi
, 2086 Newell
, 2346 Lilio
, and others. (Identified by inspection of the PDS asteroid taxonomy data set).
Asteroid family
An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions...
is a large and prominent grouping of mostly V-type
V-type asteroid
The spectra of the V-type asteroids or Vestoids are similar to that of 4 Vesta, by far the largest asteroid in this class ....
asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s in the inner asteroid belt
Asteroid belt
The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets...
in the vicinity of 4 Vesta
4 Vesta
Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, Vesta....
. Approximately 6% of main-belt asteroids belong to this family.
Characteristics
The Vestian asteroids consist of 4 Vesta4 Vesta
Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, Vesta....
, the second-most-massive of all asteroids (mean diameter of 530 km), and many small asteroids below 10 km diameter. The brightest of these, 1929 Kollaa
1929 Kollaa
1929 Kollaa is a main-belt asteroid discovered on January 20, 1939 by Yrjö Väisälä at Turku, Finland. It is named after the Kollaa River in Karelia, the focal point on the Winter War.- External links :*...
and 2045 Peking
2045 Peking
2045 Peking is a main-belt asteroid discovered on October 8, 1964 by Purple Mountain Observatory at Nanking. It is named after Peking, the capital city of the People's Republic of China.- External links :*...
, have an absolute magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...
of 12.2, which would give them a radius of about 7.5 km assuming the same high albedo as 4 Vesta
4 Vesta
Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, Vesta....
.
The family originated from an impact on asteroid 4 Vesta
4 Vesta
Vesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, Vesta....
, with the giant south-polar crater the likely impact site. The family are thought to be the source of the HED meteorite
HED meteorite
HED meteorites are a subgroup of achondrite meteorites. HED stands for "Howardite–Eucrite–Diogenite".These achondrites came from a differentiated parent body and experienced extensive igneous processing not much different from the magmatic rocks found on Earth and for this reason they closely...
s.
The Vesta family also includes a few J-type asteroid
J-type asteroid
J-type asteroids are asteroids with spectra similar to that of diogenite meteorites and so, presumably, to the deeper layers of the crust of 4 Vesta....
s (related to the V-type
V-type asteroid
The spectra of the V-type asteroids or Vestoids are similar to that of 4 Vesta, by far the largest asteroid in this class ....
), which are thought to have come from the deeper layers of Vesta's crust, and are similar to the diogenite
Diogenite
Diogenites are a subgroup of the HED meteorite group, a type of achondritic stony meteorites.-Origin and composition:Diogenites originates from deep within the crust of the asteroid 4 Vesta, and as such are part of the HED meteorite group...
meteorites
A HCM numerical analysis by (Zappala 1995) determined a large group of 'core' family members, whose proper orbital elements
Proper orbital elements
The proper orbital elements of an orbit are constants of motion of an object in space that remain practically unchanged over an astronomically long timescale...
lie in the approximate ranges
Semi-major axis
The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...
!! ep
Orbital eccentricity
The orbital eccentricity of an astronomical body is the amount by which its orbit deviates from a perfect circle, where 0 is perfectly circular, and 1.0 is a parabola, and no longer a closed orbit...
!! ip
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
>
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
This gives the approximate boundaries of the family. At the present epoch
Epoch (astronomy)
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as celestial coordinates, or elliptical orbital elements of a celestial body, where these are subject to perturbations and vary with time...
, the range of osculating
Osculating orbit
In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space is the gravitational Kepler orbit In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space (at a given moment of time) is the gravitational Kepler orbit In astronomy,...
orbital elements
Orbital elements
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are generally considered in classical two-body systems, where a Kepler orbit is used...
of these core members is
| a Semi-major axis The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape... | e | i Inclination Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit... |
|
|---|---|---|---|
| min | 2.26 AU Astronomical unit An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance.... |
0.035 | 5.0° |
| max | 2.48 AU | 0.162 | 8.3° |
The Zappala 1995 analysis found 235 core members. A search of a recent proper-element database (AstDys) for 96944 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...
s in 2005 yielded 6051 objects (about 6% of the total) lying within the Vesta-family region as per the first table above.
Interlopers
Spectroscopic analyses have shown that some of the largest Vestians are in fact interlopers. They are not of the VV-type asteroid
The spectra of the V-type asteroids or Vestoids are similar to that of 4 Vesta, by far the largest asteroid in this class ....
or J
J-type asteroid
J-type asteroids are asteroids with spectra similar to that of diogenite meteorites and so, presumably, to the deeper layers of the crust of 4 Vesta....
spectral class, but have similar orbital elements by coincidence. These include 306 Unitas
306 Unitas
306 Unitas is a typical main belt asteroid. It is classified as an S-type asteroid.It was discovered by Elia Millosevich on March 1, 1891 in Rome...
, 442 Eichsfeldia
442 Eichsfeldia
442 Eichsfeldia is a large Main belt asteroid. It is classified as a C-type asteroid and is probably composed of primitive carbonaceous material.It was discovered by Max Wolf and A...
, 1697 Koskenniemi
1697 Koskenniemi
1697 Koskenniemi is a main-belt asteroid discovered on September 11, 1940 by H. Alikoski at Turku.- External links :*...
, 1781 Van Biesbroeck
1781 Van Biesbroeck
1781 Van Biesbroeck is a main-belt asteroid discovered on October 17, 1906 by A. Kopff at Heidelberg.- External links :*...
, 2024 McLaughlin
2024 McLaughlin
2024 McLaughlin is an asteroid which was discovered at Goethe Link Observatory near Brooklyn, Indiana by the Indiana Asteroid Program....
, 2029 Binomi
2029 Binomi
The asteroid 2029 Binomi was discovered on September 11, 1969 by the Swiss astronomer Prof. Paul Wild at Zimmerwald observatory near Bern, Switzerland...
, 2086 Newell
2086 Newell
2086 Newell is the name of an asteroid which was discovered at Goethe Link Observatory near Brooklyn, Indiana by the Indiana Asteroid Program....
, 2346 Lilio
2346 Lilio
2346 Lilio is a main-belt asteroid discovered on February 5, 1934 by K. Reinmuth at Heidelberg.- External links :*...
, and others. (Identified by inspection of the PDS asteroid taxonomy data set).