956 Elisa (prov. designation: A921 PE or 1921 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]
| 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] | |
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 PlanetsbyPaul 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 lightcurveofElisa was obtained from photometric observations by Matthieu Conjat at Nice Observatory in France. Lightcurve analysis gave a well-defined rotation periodof16.492±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 albedoof0.147±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]
