1204 Renzia

1204 Renzia

Modelled shape of Renzia from its lightcurve
Discovery[1]
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	6 October 1931; 93 years ago (1931-10-06)
Designations
MPC designation	(1204) Renzia
Named after	Franz Robert Renz[2] (German-Russian astronomer)
Alternative designations	1931 TE
Minor planet category	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	2.9279 AU
Perihelion	1.5984 AU
Semi-major axis	2.2632 AU
Eccentricity	0.2937
Orbital period (sidereal)	3.40 yr (1,244 days)
Mean anomaly	110.18°
Mean motion	0° 17^m 22.2^s / day
Inclination	1.8796°
Longitude of ascending node	7.5758°
Argument of perihelion	313.75°
Earth MOID	0.5861 AU · 228.3 LD
Mars MOID	0.2114 AU
Physical characteristics
Mean diameter	10.49±2.10 km[5] 10.73±0.31 km[6] 10.82 km (derived)[4]
Synodic rotation period	7.885±0.0025 h[7] 7.885±0.015 h[8] 7.88695±0.00005 h[9] 7.88697±0.00001 h[10]
Geometric albedo	0.2103 (derived)[4] 0.222±0.014[6] 0.254±0.102[5]
Spectral type	SMASS = S[1][4]
Absolute magnitude (H)	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 designation 1931 TE) is a stony asteroid and sizable Mars-crosser on an eccentric orbit from the inner regions of the asteroid belt, approximately 10 kilometers in diameter. It was discovered by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in southwest Germany on 6 October 1931.^[3] The asteroid was named after German-Russian astronomer Franz Renz.^[2]

Orbit and classification

Renzia is a Mars-crossing asteroid, a dynamically unstable group between the main belt and the near-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 an eccentricity of 0.29 and an inclination of 2° with respect to the ecliptic.^[1] The body's observation arc begins at Heidelberg with its official discovery observation in 1931.^[3]

Impact probability

In the 1980s, British astronomer Duncan Steel calculated that Renzia has the third highest probability of impacting into Mars 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) and 8303 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 producing impact craters of at least 10 kilometers in diameter.^[13]

Physical characteristics

In the SMASS classification, Renzia is a common stony S-type asteroid.^[1][4]

Lightcurves

In September 1982, a first rotational lightcurve of Renzia was obtained from photometric observations at the Table Mountain Observatory in California.^[8] Lightcurve analysis gave a rotation period of 7.885 hours with a brightness variation of 0.42 magnitude (U=3). In February 2012, observations in the R-band by astronomers at the Palomar 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 in ecliptic 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]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Renzia measures 10.49 and 10.73 kilometers in diameter and its surface has an albedo of 0.254 and 0.222, respectively.^[5][6] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.2103 and a diameter of 10.82 kilometers based on an absolute magnitude of 12.14.^[4]

With a diameter above 10 kilometers, Renzia is larger than most sizable Mars-crossing asteroids such as 1065 Amundsenia (9.75 km), 1139 Atami (9.35 km), and 1474 Beira (15 km); but still smaller than the largest members of this dynamical group, namely, 132 Aethra, 323 Brucia, 1508 Kemi, 2204 Lyyli, and 512 Taurinensis, which are larger than 20 kilometers in diameter (in one or other given source).

Naming

This minor planet was named after German-Russian astronomer Franz Robert Renz (1860–1942) also known as Franz Franzevich Renz, who worked at the Dorpat and Pulkovo observatories. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 112).^[2]

References

1. "JPL Small-Body Database Browser: 1204 Renzia (1931 TE)" (2017-10-01 last obs.). Jet Propulsion Laboratory. Retrieved 26 October 2017.
2. Schmadel, Lutz D. (2007). "(1204) Renzia". Dictionary of Minor Planet Names – (1204) Renzia. Springer Berlin Heidelberg. p. 101. doi:10.1007/978-3-540-29925-7_1205. ISBN 978-3-540-00238-3.
3. "1204 Renzia (1931 TE)". Minor Planet Center. Retrieved 26 October 2017.
4. "LCDB Data for (1204) Renzia". Asteroid Lightcurve Database (LCDB). Retrieved 26 October 2017.
5. Alí-Lagoa, V.; Delbo', M. (July 2017). "Sizes and albedos of Mars-crossing asteroids from WISE/NEOWISE data". Astronomy and Astrophysics. 603: 8. arXiv:1705.10263. Bibcode:2017A&A...603A..55A. doi:10.1051/0004-6361/201629917. Retrieved 26 October 2017.
6. Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
7. Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 26 October 2017.
8. Harris, A. W.; Young, J. W.; Bowell, E.; Tholen, D. J. (November 1999). "Asteroid Lightcurve Observations from 1981 to 1983". Icarus. 142 (1): 173. Bibcode:1999Icar..142..173H. doi:10.1006/icar.1999.6181. Retrieved 26 October 2017.
9. Hanus, J.; Durech, J.; Oszkiewicz, D. A.; Behrend, R.; Carry, B.; Delbo, M.; et al. (February 2016). "New and updated convex shape models of asteroids based on optical data from a large collaboration network". Astronomy and Astrophysics. 586: 24. arXiv:1510.07422. Bibcode:2016A&A...586A.108H. doi:10.1051/0004-6361/201527441.
10. Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics. 587: 6. arXiv:1601.02909. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573. Retrieved 26 October 2017.
11. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 26 October 2017.
12. Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026. Retrieved 26 October 2017.
13. Steel, D. I. (August 1985). "Collisions in the solar systems. II - Asteroid impacts upon Mars". Monthly Notices of the Royal Astronomical Society. 215 (3): 369–381. Bibcode:1985MNRAS.215..369S. doi:10.1093/mnras/215.3.369. ISSN 0035-8711. Retrieved 26 October 2017.

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1204 Renzia at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 1204 Renzia at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters