Alinda family
Encyclopedia
The Alinda asteroids are a group of asteroid
s with a semi-major axis
of about 2.5 AU
and an orbital eccentricity approximately between 0.4 and 0.65. The namesake is 887 Alinda
, discovered by Max Wolf
in 1918.
These objects are held in this region by the 1:3 orbital resonance
with Jupiter
, which results in them being close to a 4:1 resonance with Earth
. An object in this resonance has its orbital eccentricity steadily increased by gravitational interactions with Jupiter until it eventually has a close encounter with an inner planet that breaks the resonance.
Some Alindas have perihelia very close to Earth
's orbit, resulting in a series of close encounters at almost exactly four-year intervals, due to the 4:1 near resonance.
One consequence of this is that if an Alinda asteroid happens to be in an unfavorable position for viewing at the time of its close approach to Earth (for instance, at a small elongation from the Sun
), then this situation can persist for decades. Indeed, as of 2010, the Alinda asteroid 1915 Quetzálcoatl
had been observed only once since 1985.
Another consequence is that some of these asteroids make repeated relatively close approaches to Earth, making them good subjects for study by Earth-based radar
. Examples are 4179 Toutatis
and 6489 Golevka
.
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 with a 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...
of about 2.5 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
and an orbital eccentricity approximately between 0.4 and 0.65. The namesake is 887 Alinda
887 Alinda
887 Alinda is an asteroid orbiting the Sun. It was originally discovered by German astronomer Max Wolf in 1918. It lies within the main asteroid belt and is the namesake for the Alinda family group of asteroids, although it is also classified as an Amor III asteroid...
, discovered by Max Wolf
Max Wolf
Maximilian Franz Joseph Cornelius Wolf was a German astronomer and a pioneer in the field of astrophotography...
in 1918.
These objects are held in this region by the 1:3 orbital resonance
Orbital resonance
In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other, usually due to their orbital periods being related by a ratio of two small integers. Orbital resonances greatly enhance the mutual gravitational influence of...
with Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, which results in them being close to a 4:1 resonance with 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...
. An object in this resonance has its orbital eccentricity steadily increased by gravitational interactions with Jupiter until it eventually has a close encounter with an inner planet that breaks the resonance.
Some Alindas have perihelia very close to 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...
's orbit, resulting in a series of close encounters at almost exactly four-year intervals, due to the 4:1 near resonance.
One consequence of this is that if an Alinda asteroid happens to be in an unfavorable position for viewing at the time of its close approach to Earth (for instance, at a small elongation from 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...
), then this situation can persist for decades. Indeed, as of 2010, the Alinda asteroid 1915 Quetzálcoatl
1915 Quetzálcoatl
1915 Quetzálcoatl is an Amor asteroid with an orbital period of 1479.7878569 days . The asteroid was discovered on March 9, 1953.-References:...
had been observed only once since 1985.
Another consequence is that some of these asteroids make repeated relatively close approaches to Earth, making them good subjects for study by Earth-based radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
. Examples are 4179 Toutatis
4179 Toutatis
4179 Toutatis/1989 AC is an Apollo, Alinda, and Mars-crosser asteroid with a chaotic orbit produced by a 3:1 resonance with the planet Jupiter, a 1:4 resonance with the planet Earth, and frequent close approaches to the terrestrial planets...
and 6489 Golevka
6489 Golevka
6489 Golevka is an Apollo, Mars-crosser and Alinda asteroid, discovered in 1991 by Eleanor F. Helin.Its name has a complicated origin. In 1995, Golevka was studied simultaneously by three radar observatories across the world: Goldstone in California, Yevpatoria RT-70 radio telescope in Ukraine and...
.
Asteroids in this family
| Name | a | e |
|---|---|---|
| 887 Alinda 887 Alinda 887 Alinda is an asteroid orbiting the Sun. It was originally discovered by German astronomer Max Wolf in 1918. It lies within the main asteroid belt and is the namesake for the Alinda family group of asteroids, although it is also classified as an Amor III asteroid... |
2.48422 | 0.56356 |
| 1429 Pemba 1429 Pemba 1429 Pemba is a main-belt asteroid discovered on July 2, 1937 by C. Jackson at Johannesburg .- External links :*... |
2.55185 | 0.33858 |
| 1550 Tito 1550 Tito 1550 Tito is a minor planet or asteroid. It was discovered on November 29, 1937 by Milorad B. Protić at Belgrade, Kingdom of Yugoslavia, now Serbia.It was named for the Yugoslav president Josip Broz Tito.... |
2.54673 | 0.30984 |
| 1607 Mavis 1607 Mavis 1607 Mavis is a main-belt asteroid discovered on September 3, 1950 by E. L. Johnson at Johannesburg .- External links :*... |
2.54783 | 0.30741 |
| 1915 Quetzálcoatl 1915 Quetzálcoatl 1915 Quetzálcoatl is an Amor asteroid with an orbital period of 1479.7878569 days . The asteroid was discovered on March 9, 1953.-References:... |
2.54207 | 0.57170 |
| 2608 Seneca 2608 Seneca 2608 Seneca is an Amor asteroid discovered on February 17, 1978 by H.-E. Schuster at La Silla.- External links :*... |
2.5035 | 0.57620 |
| 3360 Syrinx | 2.46803 | 0.74295 |
| 3628 Božněmcová 3628 Božnemcová 3628 Božněmcová is a main belt asteroid with an orbital period of 1478.2672540 days .The asteroid was discovered on November 25, 1979.-References:* * * See also: List of asteroids... |
2.53691 | 0.30052 |
| 3806 Tremaine 3806 Tremaine 3806 Tremaine is a small asteroid of the Alinda family. It was first sighted on 14 October 1975 and given the provisional designation 1975 TY5. Two more sightings occurred before the March 1, 1981 sighting by Schelte J... |
2.54058 | 0.31301 |
| 4179 Toutatis 4179 Toutatis 4179 Toutatis/1989 AC is an Apollo, Alinda, and Mars-crosser asteroid with a chaotic orbit produced by a 3:1 resonance with the planet Jupiter, a 1:4 resonance with the planet Earth, and frequent close approaches to the terrestrial planets... |
2.51005 | 0.63423 |
| 5847 Wakiya 5847 Wakiya 5847 Wakiya is a main-belt asteroid discovered on December 18, 1989 by Endate and Watanabe at Kitami.- External links :*... |
2.54442 | 0.30086 |
| 5864 Montgolfier 5864 Montgolfier 5864 Montgolfier is a main-belt asteroid discovered on September 2, 1983 by N. G. Thomas at Flagstaff.-External links:*... |
2.55866 | 0.32007 |
| 6318 Cronkite 6318 Cronkite 6318 Cronkite is a Mars-crossing asteroid discovered on November 18, 1990 by E. F. Helin at Palomar. It is named after American journalist, Walter Cronkite.- External links :*... |
2.51002 | 0.46522 |
| (6322) 1991 CQ (6322) 1991 CQ 1991 CQ is a Mars-crossing minor planet. It was discovered by Robert H. McNaught at the Siding Spring Observatory in Canberra, Australia, on February 10, 1991.-External links:*... |
2.51628 | 0.47349 |
| 6489 Golevka 6489 Golevka 6489 Golevka is an Apollo, Mars-crosser and Alinda asteroid, discovered in 1991 by Eleanor F. Helin.Its name has a complicated origin. In 1995, Golevka was studied simultaneously by three radar observatories across the world: Goldstone in California, Yevpatoria RT-70 radio telescope in Ukraine and... |
2.50768 | 0.60382 |
| (6491) 1991 OA (6491) 1991 OA 1991 OA is an Amor-type near-Earth minor planet. It was discovered by Henry E. Holt at the Palomar Observatory in San Diego County, California, on July 16, 1991. It is listed as a potentially hazardous object.-External links:*... |
2.50959 | 0.58946 |
| 7092 Cadmus 7092 Cadmus 7092 Cadmus is an asteroid of the solar system. Discovered on June 4, 1992, it has a semi-major axis of 2.5254688 AU, an eccentricity of 0.7019201, and inclination of 17.82762°.-References:... |
2.52493 | 0.70202 |
| 7345 Happer 7345 Happer 7345 Happer is a Mars-crossing asteroid discovered on July 28, 1992 by Robert H. McNaught at Siding Spring. It is named after Felix Happer, the character played by Burt Lancaster in the film Local Hero, who wanted to find a comet to be named after him.- External links :*... |
2.45047 | 0.32467 |
| (7568) 1988 VJ2 | 2.52739 | 0.33216 |
| (7569) 1989 BK | 2.54950 | 0.30348 |
| 7638 Gladman 7638 Gladman 7638 Gladman is a main-belt asteroid discovered on October 26, 1984 by E. Bowell at the Anderson Mesa Station of the Lowell Observatory. It is named for astronomer Brett Gladman in recognition of his contributions to planetary astronomy.... |
2.53634 | 0.31606 |
| (8201) 1994AH2 (8201) 1994 AH2 1994AH2 is a Apollo-type, near-earth asteroid .- Sources : rerieved 11:31 11.10.11... |
2.53362 | 0.70851 |
| 8709 Kadlu 8709 Kadlu 8709 Kadlu is a Mars-crossing asteroid discovered on May 14, 1994 by C. S. Shoemaker and E. M. Shoemaker at Palomar.- External links :*... |
2.53497 | 0.48432 |
| (9047) 1991 QF (9047) 1991 QF 1991 QF is a main-belt minor planet. It was discovered by Robert H. McNaught at the Siding Spring Observatory in Australia on August 30, 1991.-References:... |
2.52479 | 0.31661 |