887 Alinda

887 Alinda (/əˈlɪndə/) is a very eccentric, near-Earth asteroid with an Earth minimum orbit intersection distance (MOID) of 0.092 AU. It is the namesake for the Alinda group of asteroids and measures about 4 kilometers in diameter. The stony S-type asteroid was discovered by German astronomer Max Wolf at Heidelberg Observatory on 3 January 1918.

887 Alinda

Discovery[1]
Discovered by	M. Wolf
Discovery site	Heidelberg Obs.
Discovery date	3 January 1918
Designations
MPC designation	(887) Alinda
Pronunciation	/əˈlɪndə/
Named after	Alinda (city) or Aboriginal mythology[2]
Alternative designations	1918 DB
Minor planet category	Amor NEO Alinda group
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	97.42 yr (35,582 days)
Aphelion	3.8846 AU (581.13 Gm)
Perihelion	1.0731 AU (160.53 Gm)
Semi-major axis	2.4788 AU (370.82 Gm)
Eccentricity	0.56711
Orbital period (sidereal)	3.90 yr (1425.5 d)
Mean anomaly	300.87°
Mean motion	0° 15m 9.144s / day
Inclination	9.3563°
Longitude of ascending node	110.55°
Argument of perihelion	350.34°
Earth MOID	0.0907705 AU (13.57907 Gm)
Jupiter MOID	1.32066 AU (197.568 Gm)
TJupiter	3.221
Physical characteristics
Mean radius	2.1 km
Synodic rotation period	73.97 h (3.082 d)
Geometric albedo	0.31
Spectral type	B–V = 0.832 U–B = 0.436 Tholen = S
Absolute magnitude (H)	13.4

Due to its high eccentricity and semi-major axis of 0.57 and 2.5 AU, respectively, it is a typical Amor III asteroid. It has both, a 1:3 orbital resonance with Jupiter and a close to 4:1 resonance with Earth.^[3] As a result of the resonance with Jupiter that has excited the eccentricity of the orbit over the eons, the asteroid's orbit has evolved to spend time outside of the main-belt. It is the namesake for the Alinda group of asteroids.

Alinda makes close approaches to Earth, including a pass in January 2025, where it comes within 0.0821 AU (12,280,000 km; 7,630,000 mi) of Earth.^[1]

The asteroid's name had been proposed by H. Kobol. It is uncertain whether it refers to the ancient city of Alinda in modern western Turkey, or to a mythological figure of the Aboriginal Australians.^[2]