| Discovery[1] | |
|---|---|
| Discovered by | N. Chernykh |
| Discovery site | Crimean Astrophysical Obs. |
| Discovery date | 21 August 1977 |
| Designations | |
| (4391) Balodis | |
Named after | Jānis Balodis (Latvian cosmic geodesist)[2] |
| 1977 QW2 · 1977 RR2 1980 GZ | |
| main-belt · Erigone[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 39.70 yr (14,499 days) |
| Aphelion | 2.8989AU |
| Perihelion | 1.8794 AU |
| 2.3892 AU | |
| Eccentricity | 0.2134 |
| 3.69yr (1,349 days) | |
| 330.57° | |
| 0° 16m 0.84s / day | |
| Inclination | 5.3519° |
| 190.30° | |
| 108.27° | |
| Physical characteristics | |
| Dimensions | 3.36±0.17 km[4] 8.05 km(calculated)[3] |
| 3.448±0.001h[5] | |
| 0.057(assumed)[3] 0.393±0.072[4] | |
| C[3] | |
| 14.2[1][3] · 14.00[4] · 14.37±0.36[6] | |
4391 Balodis, provisional designation1977 QW2, is a dark and rare Erigoneasteroid from the inner regions of theasteroid belt, approximately 8 kilometers in diameter. It was discovered by Soviet–Russian astronomerNikolai Chernykh at theCrimean Astrophysical Observatory in Nauchnyj, on the Crimean peninsula, on 21 August 1977.[7] The asteroid was named for Latvian geodesistJānis Balodis.[2]
Balodis orbits the Sun in theinner main-belt at a distance of 1.9–2.9 AU once every 3 years and 8 months (1,349 days). Its orbit has aneccentricity of 0.21 and aninclination of 5° with respect to theecliptic.[1] Based on its orbital elements, theCollaborative Asteroid Lightcurve Link (CALL) classifies the asteroid as a member of theErigone family, which is named after its largest member and namesake,163 Erigone, also a dark body of carbonaceous composition.[3]
According to observations by NASA's space-basedWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Balodis measures 3.4 kilometers in diameter, and its surface has an exceptionally highalbedo of 0.40.[4] However, the CALL assumes a standard albedo for aC-type asteroid of 0.057 and calculates a diameter of 8.4 kilometers with anabsolute magnitude of 14.2, as the lower the albedo (reflectivity) the larger the body's diameter.[3]
In July 2010, a rotationallightcurve ofBalodis was obtained by Italian astronomer Albino Carbognani from photometric observations taken at the Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) in Italy. It showedrotation period of3.448±0.001 hours with a brightness amplitude of 0.29 inmagnitude (U=2).[5]
Thisminor planet was named after Latvian cosmicgeodesist Jānis Balodis, head of the Astronomical Observatory atUniversity of Latvia.[2]
Balodis' research includesastrometry, observations of artificial satellites using laser, as well as computational methods for astrometric interpretations of photographic plates. The Crimean minor planet service has used his algorithms for a long time.[2](The honored astronomer should not be confused with Soviet army GeneralJānis Balodis.) The official naming citation was published by theMinor Planet Center on 12 September 1992 (M.P.C. 20837).[8]
