| Discovery[1] | |
|---|---|
| Discovered by | M. F. Wolf |
| Discovery site | Heidelberg Obs. |
| Discovery date | 28 January 1917 |
| Designations | |
| (862) Franzia | |
Named after | Franz Wolf (son of the discoverer)[2] |
| A917 BG · 1948 TT1 1949 YT · A903 BA 1917 BF | |
| main-belt[1][3] · (middle) background[4][5] | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 117.04yr (42,749 d) |
| Aphelion | 3.0345AU |
| Perihelion | 2.5732 AU |
| 2.8038 AU | |
| Eccentricity | 0.0823 |
| 4.70 yr (1,715 d) | |
| 53.871° | |
| 0° 12m 35.64s / day | |
| Inclination | 13.887° |
| 300.01° | |
| 120.97° | |
| Physical characteristics | |
| 7.5236±0.0006 h[9] | |
| SMASS =S[3] | |
| 9.80[1][3] | |
862 Franzia (prov. designation:A917 BGor1917 BF) is a stonybackground asteroid from the central regions of theasteroid belt. It was discovered by German astronomerMax Wolf at theHeidelberg-Königstuhl State Observatory on 28 January 1917.[1] The commonS-type asteroid has arotation period of 7.5 hours and measures approximately 28 kilometers (17 miles) in diameter. It was named after the discoverer's son, Franz Wolf.[2]
Franzia 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 2.6–3.0 AU once every 4 years and 8 months (1,715 days;semi-major axis of 2.8 AU). Its orbit has aneccentricity of 0.08 and aninclination of 14° with respect to theecliptic.[3] The body'sobservation arc begins with one of its first observations asA903 BA atHeidelberg Observatory on 22 January 1903, or 14 years prior to its official discovery observation.[1]
Thisminor planet was named in honor of Franz Wolf, son of the discovererMax Wolf. Thenaming was also mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 84).[2] It also honors the discoverer's father, Franz Wolf, a physician and amateur astronomer who fostered his son's interest in astronomy by setting up a small observatory in the backyard when Max was sixteen.[10]
In the Bus–BinzelSMASS classification,Franzia is a common, stonyS-type asteroid.[3]
Over the last two decades, numerousphotometric observations ofFranzia have been proven challenging to determine a well definedrotation period. In August 2018, a rotationallightcurve was obtained from observations byChristophe Demeautis andRaoul Behrend. Lightcurve analysis gave a period of7.5236±0.0006 hours with a brightness variation of0.12±0.01magnitude (U=3−).[9] This result supersedes previous observations.[11]
Based on observations taken in September 2004,Brian Warner at hisPalmer Divide Observatory (716), Colorado, published an ambiguous period of7.65±0.01 and15.05±0.02 hours with an amplitude of0.10 and0.12 magnitude, respectively, depending on whether the period solution is derived from a monomodal or from a bimodal lightcurve (U=2/2). Alternatively, Warner also gave a revised period of7.52±0.01 hours and an amplitude of0.13±0.01 magnitude for his other observation taken in December 2000.[12][13][a]
In February 2011, James W. Brinsfield at the Via Capote Observatory (G69) in California measured a period of5.014±0.001 hours with an amplitude of0.10±0.03 magnitude (U=2).[14] Observations by Nicolas Esseiva and Raoul Behrend in December 2014 gave a tentative period of7.52±0.05 hours and a weak amplitude of0.07±00.01 magnitude (U=2). A basically identical period of7.52±0.05 hours with a brightness variation of0.08±0.01 magnitude was determined by French amateur astronomerRené Roy in February 2011 (U=2−).[9][11] In March 2016, the Spanish group of asteroid observers, OBAS, measures a period of16.299±0.013 hours with an amplitude of0.10±0.01 magnitude (U=2).[15]
According to the surveys carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer, the Infrared Astronomical SatelliteIRAS, and the JapaneseAkari satellite,Franzia measures (27.033±0.847), (27.26±1.4) and (28.59±0.91) kilometers in diameter and its surface has analbedo of (0.291±0.033), (0.1368±0.015) and (0.125±0.009), respectively.[6][7][8] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.2700 and a diameter of 28.05 kilometers based on anabsolute magnitude of 9.8.[11]
