![]() Shape model of Lyyli from its
lightcurve | |
Discovery [1] | |
---|---|
Discovered by | Y. Väisälä |
Discovery site | Turku Obs. |
Discovery date | 3 March 1943 |
Designations | |
(2204) Lyyli | |
Named after | Lyyli Heinänen ( Esperantist) [2] |
1943 EQ · 1968 DN | |
Mars-crosser [1] [3] | |
Orbital characteristics [1] | |
Epoch 4 September 2017 ( JD 2458000.5) | |
Uncertainty parameter 0 | |
Observation arc | 73.75 yr (26,937 days) |
Aphelion | 3.6435 AU |
Perihelion | 1.5354 AU |
2.5894 AU | |
Eccentricity | 0.4071 |
4.17 yr (1,522 days) | |
350.25 ° | |
Inclination | 20.561° |
160.45° | |
283.25° | |
Earth MOID | 0.6872 AU |
Mars MOID | 0.2547 AU |
Physical characteristics | |
25.16±2.4
km (
IRAS:11)
[4] 25.27 km (derived) [5] 27.12±1.31 km [6] | |
9.51±0.01
h
[7] 10 h [8] 11.063±0.001 h [9] 11.09±0.01 h [10] | |
0.020±0.002
[6] 0.0232±0.005 (IRAS:11) [4] 0.050±0.006 [11] 0.0537 (derived) [5] | |
SMASS = X [1] · P [11] · X [5] | |
11.61±0.44 [12] · 11.78 [5] · 12.1 [1] · 12.70 [4] [6] | |
2204 Lyyli ( prov. designation: 1943 EQ) is a dark asteroid and very eccentric Mars-crosser from the middle region of the asteroid belt, approximately 25 kilometers (16 miles) in diameter. It was discovered on 3 March 1943 by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland. [3]
Lyyli orbits the Sun in the central main-belt at a distance of 1.5–3.6 AU once every 4 years and 2 months (1,522 days). Its orbit has an eccentricity of 0.41 and an inclination of 21 ° with respect to the ecliptic. [1]
This minor planet was named in honour of Lyyli Heinänen (1903–1988), née Hartonen, a Finnish female Esperantist, professor of mathematics, amateur astronomer and former assistant of the discoverer. [2] The official naming citation was published by the Minor Planet Center on 26 May 1983 ( M.P.C. 7944). [13]
Lyyli is an X-type asteroid in the SMASS classification. [1] It has also been characterized as a P-type asteroid by NASA's NEOWISE mission. [11]
It has a rotation period of 11 hours [9] and a very low albedo between 0.02 and 0.05, according to the surveys carried out by IRAS, Akari, and WISE/NEOWISE. [4] [6] [11] Other large Mars crossing minor planets include 132 Aethra and 323 Brucia, with diameters of 43 and 36 kilometers, respectively.