| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 10 September 1929 |
| Designations | |
| (1131) Porzia | |
| Pronunciation | German:[ˈpɔʁtsi̯aː] |
Named after | Porcia Catonis (inShakespeare's play) Julius Caesar[2] |
| 1929 RO · 1939 TJ 1962 MB | |
| Mars-crosser[1][3][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 87.55 yr (31,978 days) |
| Aphelion | 2.8667AU |
| Perihelion | 1.5893 AU |
| 2.2280 AU | |
| Eccentricity | 0.2867 |
| 3.33yr (1,215 days) | |
| 165.22° | |
| 0° 17m 47.04s / day | |
| Inclination | 3.2292° |
| 100.71° | |
| 248.01° | |
| Physical characteristics | |
| Dimensions | 6.53±0.65 km[5] 7.13 km(calculated)[4] |
| 4.0±0.2h(dated)[6] 4.6584±0.0005 h[7] 4.6601±0.0006 h[8] | |
| 0.20(assumed)[4] 0.287±0.057[5] | |
| SMASS =S[1] · S[4][9] | |
| 11.94±0.70[10] · 12.00[9] · 12.90[5] · 13.0[1] · 13.10±0.14[4][6][11] | |
1131 Porzia, provisional designation1929 RO, is a stonyasteroid and sizableMars-crosser from the innermost regions of theasteroid belt, approximately 7 kilometers in diameter. It was discovered on 10 September 1929, by German astronomerKarl Reinmuth at theHeidelberg Observatory in southwest Germany.[3] The asteroid was named afterPorcia wife of Brutus, who assassinated Julius Caesar.[2]
Porzia is aMars-crossing asteroid, a dynamically unstable group between the main belt and thenear-Earth populations, crossing the orbit ofMars at 1.666 AU. It orbits the Sun at a distance of 1.6–2.9 AU once every 3 years and 4 months (1,215 days). Its orbit has aneccentricity of 0.29 and aninclination of 3° with respect to theecliptic.[1] The body'sobservation arc begins at Heidelberg, 19 days after its official discovery observation.[3]
In theSMASS taxonomy,Porzia is a common stonyS-type asteroid.[1]
Two rotationallightcurves ofPorzia were obtained by Vladimir Benishek atBelgrade Observatory shortly before its opposition in November 2009, and by French amateur astronomerRené Roy in December 2012. Lightcurve analysis gave a well definedrotation period of 4.6584 and 4.6601 hours with a brightness variation of 0.15 and 0.19magnitude, respectively (U=3/3).[7][8]
The results supersede photometric observations taken by Polish astronomerWiesław Wiśniewski in January 1990, which rendered a lightcurve with a period4.0±0.2 hours and an amplitude of 0.23 magnitude (U=2).[6]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer and its subsequentNEOWISE mission,Porzia measures 6.53 kilometers in diameter and its surface has analbedo of 0.287,[5] while theCollaborative Asteroid Lightcurve Link assumes a standardalbedo for stony asteroids of 0.20 and calculates a diameter of 7.13 kilometers with anabsolute magnitude of 13.10.[4]
This makesPorzia one of the larger mid-sizedMars-crossing asteroids comparable with1065 Amundsenia (9.75 km),1139 Atami (9.35 km),1474 Beira (8.73 km),1011 Laodamia (7.5 km),1727 Mette (est. 9 km),1235 Schorria (est. 9 km),985 Rosina (8.18 km),1310 Villigera (15.24 km) and1468 Zomba (7 km), but far smaller than the largest members of this dynamical group, namely,132 Aethra,323 Brucia,1508 Kemi,2204 Lyyli and512 Taurinensis, which are all larger than 20 kilometers in diameter.
Thisminor planet was named after the wife ofBrutus,Porcia Catonis, who kills herself at news of her husband's death in Shakespeare's playJulius Caesar.[2] The official naming citation was also published byPaul Herget inThe Names of the Minor Planets in 1955 (H 106).[2]
