878 Mildred

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878 Mildred
Discovery [1][2]
Discovered by S. B. Nicholson
H. Shapley
Discovery site Mount Wilson
Discovery date 6 September 1916
MPC designation 878
1916 f, 1985 VG6, 1991 GZ8
Nysa family[3]
Main belt Main belt
Orbital characteristics[1]
Epoch 9 December 2014 (JD 2457000.5)
Uncertainty parameter 0
Observation arc 98.59 yr
Aphelion 2.8931 AU
Perihelion 1.8281 AU
2.3606 AU
Eccentricity 0.2255
3.63 yr (1,324.7 d)
Inclination 2.0609°
Physical characteristics
Dimensions ~4 km[4]
2.660 h[1]
Spectral type

878 Mildred is a minor planet in the main belt orbiting the Sun. It is the lowest numbered, and thus the namesake, of the Mildred family of asteroids, a subgroup of the Nysa family.[3] The Mildred subgroup, and by extension 878 Mildred itself, is thought to have been formed by a recent fragmentation event from a larger asteroid.[3]


878 Mildred was originally discovered in 1916 using the 1.5 m Hale Telescope at the Mount Wilson Observatory, but was subsequently lost until it was again observed on single nights in 1985 and 1991 (a lost asteroid).[2] Initially only two observations of the asteroid were taken on 1916-09-06 which does not allow for an accurate orbital determination, however interest in the object prompted further investigation and more measurements were taken in late September and October.[4] The asteroid was re-discovered in 1991 by Gareth V. Williams.[5]

Physical properties[edit]

By comparing the asteroid's perceived brightness and the then computed distance from the Sun they arrived at an absolute visual magnitude of 14.3, which if one assumes Mars-like albedo gives an approximate diameter of 3 to 5 kilometers.[4]


  1. ^ a b c d "JPL Small-Body Database Browser: 878 Mildred (1916 f)" (2015-04-10 last obs). Retrieved September 2015. 
  2. ^ a b "IAU Circular: IAUC 5275". 1991-05-25. 
  3. ^ a b c d Cellino, A.; et al. (August 2001). "The Puzzling Case of the Nysa–Polana Family". Icarus 152 (2): 225–237. Bibcode:2001Icar..152..225C. doi:10.1006/icar.2001.6634. 
  4. ^ a b c Shapley, H.; Nicholson, S. B. (1917). "The Orbit and Probable Size of a Very Faint Asteroid (878) Mildred". Astronomical Journal 30 (710): 127–128. Bibcode:1917AJ.....30..127S. doi:10.1086/104199. 
  5. ^ "MPC staff - Gareth Williams". Minor Planet Center. International Astronomical Union. Retrieved 26 August 2014. 

External links[edit]