| Discovery[1] | |
|---|---|
| Discovered by | C.-I. Lagerkvist |
| Discovery site | Kvistaberg Stn. |
| Discovery date | 4 September 1975 |
| Designations | |
| (2744) Birgitta | |
Named after | Anna Birgitta Angelica Lagerkvist[1] (discoverer's daughter) |
| 1975 RB · 1933 QY | |
| Mars-crosser[1][2][3] | |
| Orbital characteristics[2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 84.41yr (30,830 d) |
| Aphelion | 3.0670AU |
| Perihelion | 1.5364 AU |
| 2.3017 AU | |
| Eccentricity | 0.3325 |
| 3.49 yr (1,275 d) | |
| 58.730° | |
| 0° 16m 55.92s / day | |
| Inclination | 6.7428° |
| 315.55° | |
| 44.106° | |
| Physical characteristics | |
| 2.67±0.27 km[4] 3.29 km(calculated)[3] | |
| 8.97±0.08 h[5] 8.994±0.005 h[a] 9.02 h[6] | |
| 0.20(assumed)[3] 0.304±0.061[4] | |
| Tholen =S[2] SMASS =S[2][3] B–V = 0.909[2] U–B = 0.527[2] | |
| 14.78[2][3][4] 14.84±0.12(R)[5] 15.12±0.39[7] | |
2744 Birgitta, provisional designation1975 RB, is a stonyasteroid and aMars-crosser on an eccentric orbit from the innermost regions of theasteroid belt, approximately 3 kilometers (2 miles) in diameter. It was discovered at theKvistaberg Station of theUppsala Observatory in Sweden on 4 September 1975, by Swedish astronomerClaes-Ingvar Lagerkvist, who named it after his daughter, Anna Birgitta Angelica Lagerkvist.[1] TheS-type asteroid has arotation period of 9.0 hours.[3]
Birgitta is aMars-crossing asteroid, a dynamically unstable group between themain belt and thenear-Earth populations, crossing the orbit ofMars. There are more than 5,000 numbered Mars-crosser – or approximately 1% of the overall population ofsmall Solar System bodies – with aperihelion between 1.3 and 1.666 AU.[8]
Birgitta orbits the Sun at a distance of 1.5–3.1 AU once every 3 years and 6 months (1,275 days;semi-major axis of 2.3 AU). Its orbit has aneccentricity of 0.33 and aninclination of 7° with respect to theecliptic.[2] The asteroid was first observed as1933 QY at theHeidelberg Observatory in August 1933. The body'sobservation arc begins with its official discovery observation at Kvistaberg in 1975.[1]
Birgitta is a common, stonyS-type asteroid in both theTholen andSMASS classification.[2][3]
In October 2010, a rotationallightcurve ofBirgitta was obtained fromphotometric observations by American astronomerBrian Skiff. Lightcurve analysis gave a well-definedrotation period of 8.994 hours with a brightness amplitude of 0.18magnitude (U=3).[a] The result supersedes a previous observation by the discoverer Claes-Ingvar Lagerkvist from the 1970s, which showed a period of 9.02 hours and an amplitude of 0.4 magnitude (U=2).[6] In December 2014, astronomers at thePalomar Transient Factory in California measured as similar period of 8.97 hours with a brightness variation of 0.32 magnitude (U=2).[5]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Birgitta measures 2.67 kilometers in diameter and its surface has a highalbedo of 0.304, while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 3.29 kilometers based on anabsolute magnitude of 14.78.[3]
Birgitta is a mid-sizedMars-crossing asteroid, smaller than1065 Amundsenia (10 km),1139 Atami (9 km),1474 Beira (15 km),1508 Kemi (17 km),1011 Laodamia (7.5 km),1727 Mette (9 km),1131 Porzia (7 km),1235 Schorria (5.5 km),985 Rosina (8 km),1310 Villigera (14 km) and1468 Zomba (7 km), and significantly smaller than the largest members of this dynamical group, namely,132 Aethra (40 km),2204 Lyyli (25 km) and512 Taurinensis (20 km).
Thisminor planet was named after Anna Birgitta Angelica Lagerkvist, daughter of the discovererClaes-Ingvar Lagerkvist.[1] The official naming citation was published by theMinor Planet Center on 15 May 1984 (M.P.C. 8800).[9]
