878 Mildred

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
Discovery [1][2]
Discovered byS. B. Nicholson
H. Shapley
Discovery siteMount Wilson Obs.
Discovery date6 September 1916
Designations
(878) Mildred
1916 f, 1985 VG6, 1991 GZ8
main-belt Nysa [3]
Orbital characteristics [1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc99.57 yr (36368 days)
Aphelion2.8953 AU (433.13 Gm)
Perihelion1.8286 AU (273.55 Gm)
2.3619 AU (353.34 Gm)
Eccentricity0.22580
3.63 yr (1325.9 d)
198.89°
0° 16m 17.472s / day
Inclination2.0648°
172.83°
190.14°
Physical characteristics
Dimensions~4 km[4]
2.660 h (0.1108 d)[1]
S[3]
14.7[1]

    Discovery

    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] It is named after Mildred Shapley Matthews.

    Physical properties

    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]

    References
    1. "JPL Small-Body Database Browser: 878 Mildred (1916 f)" (2015-04-10 last obs). Retrieved 3 May 2016.
    2. IAU Circular: IAUC 5275. Central Bureau for Astronomical Telegrams (Report). IAU. 25 May 1991. Retrieved 20 February 2020.
    3. 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. 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.


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