| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 1 October 1921 |
| Designations | |
| (960) Birgit | |
Named after | Birgit Asplind (daughter ofBror Asplind)[2] |
| A921 TG · 1921 KH | |
| main-belt[1][3] · (inner) background[4][5] (Florian)[6] | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 98.26yr (35,889 d) |
| Aphelion | 2.6203AU |
| Perihelion | 1.8770 AU |
| 2.2486 AU | |
| Eccentricity | 0.1653 |
| 3.37 yr (1,232 d) | |
| 123.62° | |
| 0° 17m 32.28s / day | |
| Inclination | 3.0260° |
| 249.16° | |
| 88.040° | |
| Physical characteristics | |
| 7.506±0.110 km[7] | |
| 8.85±0.05 h[8][9][a] | |
| 0.217±0.027[7] | |
| S(assumed)[8] | |
| 12.5[1][3] | |
960 Birgit (prov. designation:A921 TGor1921 KH) is abackground asteroid, approximately 8 kilometers (5 miles) in diameter, located in theFlorian region of the innerasteroid belt. It was discovered on 1 October 1921, by astronomerKarl Reinmuth at theHeidelberg Observatory in southern Germany.[1] The possiblyS-type asteroid has arotation period of 8.9 hours. It was named after Birgit Asplind, daughter of Swedish astronomerBror Asplind (1890–1954).[2]
Located in theFlorian region,[6]Birgit 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 theinner asteroid belt at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,232 days;semi-major axis of 2.25 AU). Its orbit has aneccentricity of 0.17 and aninclination of 3° with respect to theecliptic.[3] The body'sobservation arc begins at Heidelberg on 25 October 1925, three weeks after its official discovery observation.[1]
Thisminor planet was named after Birgit Asplind, daughter of Swedish astronomerBror Ansgar Asplind (1890–1954). Asteroids958 Asplinda,959 Arne and961 Gunnie are named after him and his other two children, respectively. Thenaming was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 92).[2]
Based on its determinedalbedo,Birgit is an assumedS-type asteroid.[8] The albedo determined by theWide-field Infrared Survey Explorer (WISE) for this asteroid agrees with that assumption(see below).
In February 2007, a rotationallightcurve ofBirgit was obtained fromphotometric observations by Agnieszka Kryszczyńska atPoznań Observatory, Poland, and international collaborators. Lightcurve analysis gave arotation period of8.85±0.05 hours with a brightness variation of0.28±0.02magnitude (U=2+).[9][a] The result supersedes observations by Federico Manzini, Roberto Crippa, andPierre Antonini from August 2005, who determined a poorly rated period of17.3558±0.0005 hours with an amplitude of0.25±0.01 magnitude (U=1+).[10]
According to the survey carried out by theNEOWISE mission of NASA's WISE telescope,Birgit measures7.506±0.110 kilometers in diameter and its surface has analbedo of0.217±0.027.[7] Another published measurement by the WISE team gives amean diameter of8.154±0.566 km with an albedo of0.291±0.044.[5] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for astony asteroid of 0.20 and calculates a diameter of 9.40 kilometers based on anabsolute magnitude of 12.5.[8]
