_Renzia.png) Modelled shape ofRenzia from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | K. Reinmuth |
| Discovery site | Heidelberg Obs. |
| Discovery date | 6 October 1931; 94 years ago (1931-10-06) |
| Designations | |
| (1204) Renzia | |
Named after | Franz Robert Renz[2] (German-Russian astronomer) |
| 1931 TE | |
| Mars-crosser[1][3][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 85.99 yr (31,407 days) |
| Aphelion | 2.9279AU |
| Perihelion | 1.5984 AU |
| 2.2632 AU | |
| Eccentricity | 0.2937 |
| 3.40yr (1,244 days) | |
| 110.18° | |
| 0° 17m 22.2s / day | |
| Inclination | 1.8796° |
| 7.5758° | |
| 313.75° | |
| Earth MOID | 0.5861 AU · 228.3LD |
| Mars MOID | 0.2114 AU |
| Physical characteristics | |
| 10.49±2.10 km[5] 10.73±0.31 km[6] 10.82 km(derived)[4] | |
| 7.885±0.0025 h[7] 7.885±0.015h[8] 7.88695±0.00005 h[9] 7.88697±0.00001 h[10] | |
| 0.2103(derived)[4] 0.222±0.014[6] 0.254±0.102[5] | |
| SMASS =S[1][4] | |
| 11.736±0.002(R)[7] · 12.00[1][5] · 12.13±0.43[11] · 12.14[4] · 12.14±0.09[8][12] · 12.20[6] | |
1204 Renzia (provisional designation1931 TE) is a stonyasteroid and sizableMars-crosser on an eccentric orbit from the inner regions of theasteroid belt, approximately 10 kilometers in diameter. It was discovered by astronomerKarl Reinmuth at theHeidelberg-Königstuhl State Observatory in southwest Germany on 6 October 1931.[3] The asteroid was named after German-Russian astronomerFranz Renz.[2]
Renzia is aMars-crossing asteroid, a dynamically unstable group between themain belt and thenear-Earth populations, crossing the orbit of Mars at 1.666 AU. It orbits the Sun at a distance of 1.6–2.9 AU once every 3 years and 5 months (1,244 days). Its orbit has aneccentricity of 0.29 and aninclination of 2° with respect to theecliptic.[1] The body'sobservation arc begins at Heidelberg with its official discovery observation in 1931.[3]
In the 1980s, British astronomerDuncan Steel calculated that Renzia has the third highest probability ofimpacting intoMars among a large sample of Mars-crossing asteroids. With a collision probability of 4.84 impacts per billion orbits,[13] Renzia is only behind the asteroids(9801) 1997 FX (4.96) and8303 Miyaji (5.08), which are both significantly smaller. He also calculated that such an impact event may occur every 300,000 years, for an assumed population of 10 thousand Mars-crossers larger than 1 kilometer producingimpact craters of at least 10 kilometers in diameter.[13]
In theSMASS classification, Renzia is a common stonyS-type asteroid.[1][4]
In September 1982, a first rotationallightcurve of Renzia was obtained from photometric observations at theTable Mountain Observatory in California.[8] Lightcurve analysis gave arotation period of 7.885 hours with a brightness variation of 0.42magnitude (U=3). In February 2012, observations in the R-band by astronomers at thePalomar Transient Factory gave an identical period with an amplitude of 0.49 magnitude (U=2).[7]
Two 2016-studies also modeled the asteroid's lightcurve. They gave a concurring sidereal period of 7.88695 and 7.88697 hours.[9][10] Each of the studies also determined two spin axis inecliptic coordinates (λ, β): (142.0°, −50.0°) and (305.0°, −45.0°),[9] as well as (130.0°, −44.0°) and (312.0°, −51.0°).[10]
According to the surveys carried out by the JapaneseAkari satellite and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Renzia measures 10.49 and 10.73 kilometers in diameter and its surface has analbedo of 0.254 and 0.222, respectively.[5][6] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.2103 and a diameter of 10.82 kilometers based on anabsolute magnitude of 12.14.[4]
With a diameter above 10 kilometers, Renzia is larger than most sizableMars-crossing asteroids such as1065 Amundsenia (9.75 km),1139 Atami (9.35 km), and1474 Beira (15 km); but still smaller than the largest members of this dynamical group, namely,132 Aethra,323 Brucia,1508 Kemi,2204 Lyyli, and512 Taurinensis, which are larger than 20 kilometers in diameter (in one or other given source).
Thisminor planet was named after German-Russian astronomer Franz Robert Renz (1860–1942) also known as Franz Franzevich Renz, who worked at theDorpat andPulkovo observatories. The official naming citation was mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 112).[2]
