(99907) 1989 VA
Encyclopedia
1989 VA is an Aten asteroid
located in Venus
' zone of influence that has frequent close encounters with the Earth
. It was discovered on 2 November 1989 by C. S.
, E. M. Shoemaker
and David H. Levy
at Mount Palomar
and was the eighth Aten asteroid discovered.
1989 VA was the first asteroid discovered with such a small semi-major axis
(0.729 au
, about the same as Venus), breaking 2100 Ra-Shalom
's distance record (0.832 au), which had held for over a decade. It remained the asteroid with the smallest known semi-major axis for five years until the discovery of 1994 GL (0.684 au), which was the first asteroid discovered closer to the Sun
than Venus.
Being so close to Venus, it is also the first asteroid discovered within Venus' zone of influence. This means that it is close enough to Venus for the planet to capture 1989 VA into a co-orbital relationship. Though it is not a Venus co-orbital at the moment, it may become one in the future and may have been one in the past. Currently, the only known Venus co-orbital is . Of the six known objects in Venus' zone of influence, 1989 VA is the largest at about 800 metres. All of these objects, like 1989 VA, have eccentric orbits that cross Mercury
's and Earth's orbits as well.
1989 VA briefly held the title to Aten asteroid with the highest eccentricity (0.595), which was higher than the record the Earth co-orbital 3753 Cruithne
(0.516) had set a few months earlier. 1991 VE (0.664) claimed that record two years later.
The combination of a small semi-major axis and high eccentricity made 1989 VA the first Aten asteroid discovered to get closer to the Sun (0.295 au) than Mercury ever does. 2340 Hathor
(the second Aten discovered, in 1976) had the smallest perihelion (0.464 au) earlier, which was about the same distance as Mercury's aphelion (0.467 au). It was not until (0.277 au) was discovered that an Aten asteroid with a lower perihelion was found.
1989 VA's eccentric orbit takes it out past the Earth, where it has encounters of about 0.15 to 0.20 au about every 3 to 5 years around October–November. It was discovered during its 1989 encounter and was about 0.17 au away at the time. Further observations were made in October 2002 and during the most recent close encounter in November 2007.
1989 VA is an 800 metre diameter type Sq asteroid with a rotation period of 2.5 hours.
Aten asteroid
The Aten asteroids are a group of near-Earth asteroids, named after the first of the group to be discovered . They are defined by having semi-major axes of less than one astronomical unit...
located in Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
' zone of influence that has frequent close encounters with the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
. It was discovered on 2 November 1989 by C. S.
Carolyn S. Shoemaker
Carolyn Jean Spellmann Shoemaker is an American astronomer and is a co-discoverer of Comet Shoemaker–Levy 9. She holds the record for most comets discovered by an individual.- Personal life :...
, E. M. Shoemaker
Eugene Merle Shoemaker
Eugene Merle Shoemaker , American geologist, was one of the founders of the fields of planetary science....
and David H. Levy
David H. Levy
David H. Levy is a Canadian astronomer and science writer most famous for his co-discovery in 1993 of Comet Shoemaker–Levy 9, which collided with the planet Jupiter in 1994.-Biography:...
at Mount Palomar
Palomar Observatory
Palomar Observatory is a privately owned observatory located in San Diego County, California, southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. At approximately elevation, it is owned and operated by the California Institute of Technology...
and was the eighth Aten asteroid discovered.
1989 VA was the first asteroid discovered with such a small semi-major axis
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...
(0.729 au
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
, about the same as Venus), breaking 2100 Ra-Shalom
2100 Ra-Shalom
The asteroid 2100 Ra-Shalom was discovered in 1978 by Eleanor F. Helin. It was the second asteroid in the Aten class, after the discovery of 2062 Aten in 1976, also by Helin. The Atens have a semi-major axis of less than 1 AU; of the Atens, Ra-Shalom is one of the asteroids with the smallest...
's distance record (0.832 au), which had held for over a decade. It remained the asteroid with the smallest known semi-major axis for five years until the discovery of 1994 GL (0.684 au), which was the first asteroid discovered closer to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
than Venus.
Being so close to Venus, it is also the first asteroid discovered within Venus' zone of influence. This means that it is close enough to Venus for the planet to capture 1989 VA into a co-orbital relationship. Though it is not a Venus co-orbital at the moment, it may become one in the future and may have been one in the past. Currently, the only known Venus co-orbital is . Of the six known objects in Venus' zone of influence, 1989 VA is the largest at about 800 metres. All of these objects, like 1989 VA, have eccentric orbits that cross Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
's and Earth's orbits as well.
1989 VA briefly held the title to Aten asteroid with the highest eccentricity (0.595), which was higher than the record the Earth co-orbital 3753 Cruithne
3753 Cruithne
3753 Cruithne is an asteroid in orbit around the Sun in approximate 1:1 orbital resonance with the Earth. It is a periodic inclusion planetoid orbiting the Sun in an apparent horseshoe orbit. It has been incorrectly called "Earth's second moon", but it is only a quasi-satellite. Cruithne never...
(0.516) had set a few months earlier. 1991 VE (0.664) claimed that record two years later.
The combination of a small semi-major axis and high eccentricity made 1989 VA the first Aten asteroid discovered to get closer to the Sun (0.295 au) than Mercury ever does. 2340 Hathor
2340 Hathor
2340 Hathor is an asteroid that was discovered on October 22, 1976 by C.T. Kowal at Palomar. Like the other objects of Aten type, Hathor is named for an Egyptian deity. Known as a sky-goddess and the daughter of Ra, Hathor was also identified with Aphrodite. The name was proposed by E...
(the second Aten discovered, in 1976) had the smallest perihelion (0.464 au) earlier, which was about the same distance as Mercury's aphelion (0.467 au). It was not until (0.277 au) was discovered that an Aten asteroid with a lower perihelion was found.
1989 VA's eccentric orbit takes it out past the Earth, where it has encounters of about 0.15 to 0.20 au about every 3 to 5 years around October–November. It was discovered during its 1989 encounter and was about 0.17 au away at the time. Further observations were made in October 2002 and during the most recent close encounter in November 2007.
1989 VA is an 800 metre diameter type Sq asteroid with a rotation period of 2.5 hours.