Astronomy:991 McDonalda

From HandWiki
991 McDonalda
Discovery
Discovered byO. Struve
Discovery siteWilliams Bay
Discovery date24 October 1922
Designations
(991) McDonalda
1922 NB, 1949 PF, 1950 WG, 1953 GT1, 1975 EE6
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc80.10 yr (29255 days)
|{{{apsis}}}|helion}}3.6381 astronomical unit|AU (544.25 Gm)
|{{{apsis}}}|helion}}2.6458 AU (395.81 Gm)
3.1419 AU (470.02 Gm)
Eccentricity0.15791
Orbital period5.57 yr (2034.2 d)
Mean anomaly351.48°
Mean motion0° 10m 37.092s / day
Inclination2.0696°
Longitude of ascending node63.255°
254.682°
Physical characteristics
Mean radius15.705±1.05 km
Geometric albedo0.0638±0.009
C
Absolute magnitude (H)11.12


991 McDonalda is a Themistian asteroid. It was discovered by Otto Struve in 1922 at the Yerkes Observatory in Williams Bay, Wisconsin, United States. It is named after the McDonald Observatory, which Struve helped found in 1939.[2]

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