3309 Brorfelde, provisional designation 1982 BH, is a nearly spheroidal, binary[a] Hungaria asteroid from the inner regions of the asteroid belt, approximately 4 kilometers in diameter. It was discovered on 28 January 1982, by Danish astronomers Kaare Jensen and Karl Augustesen at the Brorfelde Observatory near Holbæk, Denmark.[3] It was named for the discovering observatory and the village where it is located.[2]
| Discovery [1] | |
|---|---|
| Discovered by | K. Jensen K. Augustesen |
| Discovery site | Brorfelde Obs. |
| Discovery date | 28 January 1982 |
| Designations | |
| (3309) Brorfelde | |
Named after | Brorfelde Observatory (discovering observatory)[2] |
| 1982 BH | |
| main-belt · Hungaria [3][4] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 35.25 yr (12,876 days) |
| Aphelion | 1.9143 AU |
| Perihelion | 1.7208 AU |
| 1.8175 AU | |
| Eccentricity | 0.0532 |
| 2.45 yr (895 days) | |
| 76.394° | |
| 0° 24m 7.92s / day | |
| Inclination | 21.136° |
| 29.797° | |
| 218.43° | |
| Known satellites | 1 [5][a] |
| Physical characteristics | |
| Dimensions | 3.78±0.60 km[6] 3.91 km (derived)[4] 5.038±0.083 km[7] |
| 2.503±0.001 h[8] 2.5041±0.0002 h[5][9] 2.5042±0.0001 h[10] 2.5046±0.0003 h[11] 6±2 h[12] 8±1 h[13] 9.3788±0.0022 h[14] | |
| 0.253±0.060[7] 0.2747 (derived)[4] 0.408±0.060[7] 0.46±0.24[6] | |
| SMASS = S [1] · S [4] | |
| 13.4±0.2 (R)[5] · 13.584±0.001 (R)[14] · 13.60[6][7] · 13.7[1] · 13.9[9] · 13.97±0.09[12] · 14.062±0.064[4][15] | |
Orbit and classification
Brorfelde is a bright stony asteroid and member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.7–1.9 AU once every 2 years and 5 months (895 days). Its orbit has an eccentricity of 0.05 and an inclination of 21° with respect to the ecliptic.[1] The body's observation arc begins with its official discovery observation, as no precoveries were taken, and no prior identifications were made.[3]
Physical characteristics
On the SMASS taxonomic scheme, Brorfelde is a common stony S-type asteroid.[1]
Photometry
Between 2005 and 2010, astronomers Brian Warner and Petr Pravec obtained a large number of rotational lightcurves of Brorfelde. Best rated lightcurve analysis gave a rotation period between 2.5041 and 2.5046 hours with a brightness amplitude between 0.09 and 0.13 in magnitude, indicating that the body has a nearly spheroidal shape (U=3/3/3).[9][10]
These results superseded photometric observations taken by Wiesław Z. Wiśniewski in the 1990s (U=2),[12] and by Federico Manzini and René Roy in 2005 and 2009, respectively (U=2-/n.a.),[13] as well as observations taken at the Palomar Transient Factory in 2010, which gave an incorrect period solution of more than 9 hours (U=1).[14]
Satellite
During the photometric observation in 2005, it was revealed that Brorfelde is a binary asteroid. Its asteroid moon has an orbital period of 18.48±0.01 hours, and measures approximately 1 kilometer in diameter, based on a mean-diameter ratio of 0.26±0.02 for the system's secondary and primary body.[a][5] In January 2014, repeated observations by Brian Warner confirmed a period of 2.503 and 18.51 hours for the primary and secondary, respectively (U=3),[8] with several online-published lightcurve plots.[b]
Diameter and albedo
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Brorfelde measures 3.78 kilometers in diameter, and its surface has an albedo of 0.46 (most recent result only).[6] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.2747 and a diameter of 3.91 kilometers with an absolute magnitude of 14.062.[4]
Naming
This minor planet was named on the occasion of the Brorfelde Observatory's 40th anniversary. Brorfelde was the observatory's first minor planet discovery.[2] The approved naming citation was published by the Minor Planet Center on 7 September 1987 (M.P.C. 12210).[16]
Notes
References
External links
- Lightcurve plot of 3309 Brorfelde, Palmer Divide Observatory, B. D. Warner (2009)
- (3309) Brorfelde, datasheet, johnstonsarchive.net
- Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
- Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
- Dictionary of Minor Planet Names, Google books
- Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- 3309 Brorfelde at AstDyS-2, Asteroids—Dynamic Site
- 3309 Brorfelde at the JPL Small-Body Database
