| Discovery[1] | |
|---|---|
| Discovered by | R. Schorr |
| Discovery site | Bergedorf Obs. |
| Discovery date | 9 May 1917 |
| Designations | |
| (869) Mellena | |
Named after | Werner von Melle (mayor of Hamburg)[2] |
| A917 JB · 1931 RC 1944 OB · 1952 DL2 1917 BV | |
| main-belt[1][3] · (middle) background[4][5] | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 102.66yr (37,496 d) |
| Aphelion | 3.2807AU |
| Perihelion | 2.0966 AU |
| 2.6887 AU | |
| Eccentricity | 0.2202 |
| 4.41 yr (1,610 d) | |
| 90.376° | |
| 0° 13m 24.96s / day | |
| Inclination | 7.8385° |
| 154.88° | |
| 107.09° | |
| Physical characteristics | |
| 6.5155±0.0005 h[9] | |
| 11.9[1][3] | |
869 Mellena (prov. designation:A917 JBor1917 BV) is a darkbackground asteroid from the central region of theasteroid belt. It was discovered on 9 May 1917, by astronomerRichard Schorr at theBergedorf Observatory in Hamburg.[1] The carbonaceousC-type asteroid has a shorter than averagerotation period of 6.5 hours and measures approximately 19 kilometers (12 miles) in diameter. It was named afterWerner von Melle (1853–1937), mayor of Hamburg, who founded the discovering observatory.[2]
Mellena is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[4][5] It orbits the Sun in thecentral asteroid belt at a distance of 2.1–3.3 AU once every 4 years and 5 months (1,610 days;semi-major axis of 2.69 AU). Its orbit has aneccentricity of 0.22 and aninclination of 8° with respect to theecliptic.[3]
Mellena was discovered by German astronomerRichard Schorr at theBergedorf Observatory in Hamburg on 9 May 1917.[1] On the following night, it was independently discovered byMax Wolf atHeidelberg Observatory on 10 May 1917.[2] TheMinor Planet Center, however, only credits the first discoverer. Schorr only discovered one more asteroid,1240 Centenaria, and was honored with the naming of Mars-crosser1235 Schorria, discovered by Wolf.Mellena'sobservation arc begins atAlgiers Observatory in Northern Africa on 26 March 1930, almost 13 years after its official discovery observation at Bergedorf.[1]
Thisminor planet was named afterWerner von Melle (1853–1937), who was the mayor of Hamburg, Germany, in1915 and during1918–1919. He promoted the establishment of theUniversity of Hamburg and founded the Bergedorf–Hamburg Observatory where this minor planet was discovered. Thenaming was also mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 85).[2]
In both the Tholen- and SMASS-like taxonomy of theSmall Solar System Objects Spectroscopic Survey (S3OS2) as well as in theSDSS-based taxonomy,Mellena is a common, carbonaceousC-type asteroid.[5][10][11]
In May 2010, a rotationallightcurve ofMellena was obtained fromphotometric observations byRobert Stephens at the Santana (646) and GMARS (G79) observatories in California. Lightcurve analysis gave a well-definedrotation period of6.5155±0.0005 hours with a brightness variation of0.27±0.03magnitude (U=3).[9] Subsequent observations were taken by Andrea Ferrero at the Bigmuskie Observatory (B88) in Mombercelli, Italy (U=2),[12] and Larry Owings at the Barnes Ridge Observatory in California in June 2010 (U=3),[13] as well as by Albino Carbognani Astronomical at the OAVdA Observatory (B04) in July 2010 (U=3−).[14] These observations gave a concurring period of (6.510±0.003), (6.510±0.001) and (6.515±0.001) hours with an amplitude of (0.25±0.02), (0.20±0.02) and (0.26±0.03) magnitude, respectively.[12]
According to the surveys carried out by the JapaneseAkari satellite, the Infrared Astronomical SatelliteIRAS, and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE),Mellena measures (18.45±0.32), (18.52±0.8) and (21.193±0.090) kilometers in diameter and its surface has analbedo of (0.058±0.002), (0.0565±0.005) and (0.057±0.022), respectively.[6][7][8] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.0884 and a diameter of 18.64 kilometers based on anabsolute magnitude of 11.9.[12] Alternativemean diameter measurements published by the WISE team include (15.23±3.47 km), (16.39±3.30 km), (17.77±0.46 km) and (21.953±0.153 km) with corresponding albedos of (0.12±0.17), (0.09±0.04), (0.065±0.009) and (0.0377±0.0020).[5][12]
