Discovery [1] | |
---|---|
Discovered by | K. Reinmuth |
Discovery site | Heidelberg Obs. |
Discovery date | 8 August 1921 |
Designations | |
(956) Elisa | |
Pronunciation | German: [ɛˈliːzaː] [2] English: /ɪˈlaɪsə/ [3] |
Named after | Elisa Reinmuth (discoverer's mother) [4] |
A921 PE ·1959 NB 1921 JW | |
main-belt [1] [5] ·(inner) Flora [6] | |
Orbital characteristics [5] | |
Epoch 31 May 2020 (JD 2459000.5) | |
Uncertainty parameter 0 | |
Observation arc | 98.41 yr (35,943 d) |
Aphelion | 2.7686 AU |
Perihelion | 1.8282 AU |
2.2984 AU | |
Eccentricity | 0.2046 |
3.48 yr (1,273 d) | |
136.20° | |
0° 16m 58.44s / day | |
Inclination | 5.9626° |
192.64° | |
125.36° | |
Physical characteristics | |
16.492±0.006 h [9] [10] | |
V (S3OS2) [11] | |
12.1 [1] [5] | |
956 Elisa ( prov. designation:A921 PEor1921 JW) is a Flora asteroid from the inner regions of the asteroid belt, approximately 10.5 kilometers (6.5 miles) in diameter. It was discovered on 8 August 1921, by German astronomer Karl Reinmuth at the Heidelberg Observatory. [1] The V-type asteroid has a rotation period of 16.5 hours. It was named after Elisa Reinmuth, mother of the discoverer. [4]
When applying the synthetic hierarchical clustering method (HCM) by Nesvorný, Elisa is a member of the Flora family ( 402 ), a giant asteroid family and the largest family of stony asteroids in the main-belt. [6] [12] : 23 However, according to another HCM-analysis by Milani and Knežević (AstDys), it is a background asteroid as this analysis does not recognize the Flora asteroid clan. [13]
Elisa orbits the Sun in the inner asteroid belt at a distance of 1.8–2.8 AU once every 3 years and 6 months (1,273 days; semi-major axis of 2.3 AU). Its orbit has an eccentricity of 0.20 and an inclination of 6° with respect to the ecliptic. [5] The body's observation arc begins at Heidelberg Observatory on 9 August 1921, the night after its official discovery observation. [1]
This minor planet was named after Elisa Reinmuth, mother of the discoverer Karl Reinmuth. The naming was mentioned in The Names of the Minor Planets by Paul Herget in 1955 ( H 92 ). [4]
In both the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), Elisa is a V-type asteroid. [6] [11] These asteroids are also called "Vestoids", thought to have originates from an ejecting impact event on 4 Vesta. [14] [15]
In July 2008, a rotational lightcurve of Elisa was obtained from photometric observations by Matthieu Conjat at Nice Observatory in France. Lightcurve analysis gave a well-defined rotation period of 16.492±0.006 hours with a brightness variation of 0.36±0.02 magnitude ( U=3 ). [9] [10] During the same opposition, Vladimir Benishek at Belgrade Observatory ( 057 ) and Lucy Lim with the Spitzer -team determined a period for this asteroid of 16.5075±0.0007 and 16.494±0.001 hours with an amplitude of 0.37±0.02 and 0.35±0.02 magnitude, respectively ( U=3/3– ). [8] [16]
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE) and the Spitzer Space Telescope, Elisa measures 10.474±0.208 and 10.6±0.5 kilometers in diameter and its surface has an albedo of 0.147±0.022 and 0.142±0.022, respectively. [7] [8] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a Flora asteroid of 0.24 and calculates a diameter of 10.31 kilometers based on an absolute magnitude of 12.1. [9] The WISE team has also published two smaller mean-diameters of 8.02±1.09 km and 8.40±0.67 km with higher albedos of 0.41±0.21 and 0.362±0.071. [6] [9]