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] | |
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]
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]
On the SMASS taxonomic scheme, Brorfelde is a common stony S-type asteroid. [1]
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These results superseded photometric observations taken by Wiesław Z. Wiśniewski in the 1990s ( U=2 ), [12] and by Federico Manzini and René Roy in 2005 and 2009, respectively (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]
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]
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]
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]