| Discovery[1] | |
|---|---|
| Discovered by | B. Jekhovsky |
| Discovery site | Algiers Obs. |
| Discovery date | 27 March 1922 |
| Designations | |
| (976) Benjamina | |
Named after | Benjamin Jekhowsky Jr. (discoverer's son)[2] |
| A922 FD · A910 AB 1922 LU · 1910 AB | |
| main-belt[1] · (outer)[3] background[4][5] | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 109.34yr (39,935 d) |
| Aphelion | 3.5276AU |
| Perihelion | 2.8744 AU |
| 3.2010 AU | |
| Eccentricity | 0.1020 |
| 5.73 yr (2,092 d) | |
| 43.757° | |
| 0° 10m 19.56s / day | |
| Inclination | 7.7121° |
| 243.76° | |
| 319.60° | |
| Physical characteristics | |
| 9.701±0.002 h[9][10] | |
| (354.0°, 80.0°) (λ1/β1)[5][11] | |
| 9.3[1][3] | |
976 Benjamina (prov. designation:A922 FDor1922 LU) is a darkbackground asteroid from the outer regions of theasteroid belt, approximately 81 kilometers (50 miles) in diameter. It was discovered on 27 March 1922, by Russian-French astronomerBenjamin Jekhowsky at theAlgiers Observatory in North Africa.[1] The largeX/D-type asteroid has arotation period of 9.7 hours and is likely regular in shape. It was named after the discoverer's son.[2]
Benjamina is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[4][5] It orbits the Sun in theouter main-belt at a distance of 2.9–3.5 AU once every 5 years and 9 months (2,092 days;semi-major axis of 3.2 AU). Its orbit has aneccentricity of 0.10 and aninclination of 8° with respect to theecliptic.[3]
The asteroid was first observed asA910 AB (1910 AB) atHeidelberg Observatory on 8 January 1910. The body'sobservation arc begins at the CrimeanSimeiz Observatory in September 1930, more than 7 years after its official discovery observation atAlgiers Observatory in March 1922.[1]
Thisminor planet was named after Benjamin Jekhowsky Jr., son of discovererBenjamin Jekhowsky. Thenaming was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 93).[2]
.jpg)
In theTholen classification, and based on a noisy spectra (:),Benjamina is anX-type asteroid, somewhat similar to that of a darkD-type (XD), which are common in the outer asteroid belt and among theJupiter trojan population.[3]
In September 2004, a rotationallightcurve ofBenjamina was obtained fromphotometric observations by French amateur astronomerLaurent Bernasconi. Lightcurve analysis gave a well-definedrotation period of9.701±0.002 hours with a brightness variation of0.19±0.01magnitude (U=3). Follow-up observation by his collegeRené Roy in March 2018, determined a concurring period of9.705±0.003 hours but with a much higher amplitude of0.60±0.10 magnitude (U=2).[9][10] The objects first lightcurve was obtained by Colin Bembrick atMount Tarana Observatory (431) in Australia in March 2003. It showed a period of9.746±0.003 hours with an amplitude of0.18±0.02 magnitude (U=2). The overall amplitude suggest a rather regular shape with a ratio of 0.86 for the length of the a and b axes.[12]
In 2018, Czech astronomersJosef Ďurech andJosef Hanuš published a modeled lightcurve using photometric data from theGaia probe's second data release. It showed a sidereal period of9.7080±0.0002 hours, and gave aspin axis at (354.0°, 80.0°) inecliptic coordinates (λ, β).[5][11]
According to the surveys carried out by the JapaneseAkari satellite, the Infrared Astronomical SatelliteIRAS, and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE),Benjamina measures79.94±1.16,80.53±2.5 and83.195±0.542 kilometers in diameter with analbedo of its surface of0.057±0.002,0.0559±0.004 and0.052±0.006, respectively.[6][7][8] Additional measurements by the WISE telescope were published giving a mean-diameter as low as71.372±27.828 km, and as high as85.251±1.364 km.[5][10]
TheCollaborative Asteroid Lightcurve Link adopts the result from IRAS, that is, an albedo of 0.0559 and a diameter of 80.53 kilometers based on anabsolute magnitude of 9.22.[10]
The asteroid had been observed in 7stellaroccultation events since 2003.[13] On 19 July 2003 the mag. 5.7 starHIP 88816 was occulted by the asteroid,[14] and was observed at 11 stations; 1 in Argentina, 3 in New Zealand, and 7 in Australia. From these observations, the best-fit ellipse measures 85.2 x 56.2 ±12.4 kilometres.
