Alinda family

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The Alinda asteroids are a group of asteroids 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 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 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 2004, the Alinda asteroids 3360 Syrinx and 1915 Quetzálcoatl had not been observed since 1985, and 2608 Seneca had not been observed since 1994.

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.

Some Alinda asteroids are shown below:

Name	a	e
887 Alinda	2.48422	0.56356
1429 Pemba	2.55185	0.33858
1550 Tito	2.54673	0.30984
1607 Mavis	2.54783	0.30741
1915 Quetzálcoatl	2.54207	0.57170
2608 Seneca	2.5035	0.57620
3360 Syrinx	2.46803	0.74295
3628 Božněmcová	2.53691	0.30052
3806 Tremaine	2.54058	0.31301
4179 Toutatis	2.51005	0.63423
5847 Wakiya	2.54442	0.30086
5864 Montgolfier	2.55866	0.32007
6318 Cronkite	2.51002	0.46522
(6322) 1991 CQ	2.51628	0.47349
6489 Golevka	2.50768	0.60382
(6491) 1991 OA	2.50959	0.58946
7092 Cadmus	2.52493	0.70202
7345 Happer	2.45047	0.32467
(7568) 1988 VJ2	2.52739	0.33216
(7569) 1989 BK	2.54950	0.30348
7638 Gladman	2.53634	0.31606
(8201) 1994AH2	2.53362	0.70851
8709 Kadlu	2.53497	0.48432
(9047) 1991 QF	2.52479	0.31661

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