335 Roberta
| Discovery | |
|---|---|
| Discovered by | Anton Staus |
| Discovery date | 1 September 1892 |
| Designations | |
| (335) Roberta | |
Named after | Karl Robert Osten-Sacken |
| 1892 C | |
| Main belt | |
| Orbital characteristics[1] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 123.58 yr (45137 d) |
| Aphelion | 2.9014 AU (434.04 Gm) |
| Perihelion | 2.04926 AU (306.565 Gm) |
| 2.47530 AU (370.300 Gm) | |
| Eccentricity | 0.17212 |
| 3.89 yr (1422.5 d) | |
Average orbital speed | 18.93 km/s |
| 355.460° | |
| 0° 15m 11.095s / day | |
| Inclination | 5.1005° |
| 148.454° | |
| 140.006° | |
| Earth MOID | 1.03587 AU (154.964 Gm) |
| Jupiter MOID | 2.2733 AU (340.08 Gm) |
| TJupiter | 3.456 |
| Physical characteristics | |
| Dimensions | 89.07±2.0 km[1] |
| 12.054 h (0.5023 d) | |
| 0.0580±0.003[1] 0.058[2] | |
| B–V = 0.624 U–B = 0.235 FP (Tholen) B (SMASS)[1] | |
| 8.96[1] | |
Roberta (minor planet designation: 335 Roberta) is a large main belt asteroid. It was discovered on 1 September 1892, by German astronomer Anton Staus at Heidelberg Observatory.[3] Roberta was the 12th asteroid that was discovered using photography, and the only asteroid discovery made by Staus.[4]
Photometric observations of this asteroid from multiple sites during 2007 gave a light curve with a period of 12.054 ± 0.003 hours and a brightness variation of 0.13 ± 0.02 in magnitude. This agrees with a result reported in 1992, but differs from period estimates of 8.03 hours and 4.349 reported in 1987 and 2001, respectively.[5]
Under the SMASS classification taxonomy, this asteroid is listed as a B-type; a group that combines both the Tholen B and F types. The spectrum of this object suggests the presence of magnetite (Fe3O4), which gives it the spectrally-blue coloration that is a characteristic of this SMASS class. The spectrum of this asteroid also displays a band feature near 2.9 μm that indicate the presence of a hydrated mineral. This suggests that the asteroid has undergone significant water-based alteration.[2]
335 Roberta was identified as one of three asteroids that were likely to be a parent body for chondrites along with 449 Hamburga and 304 Olga.[6] All three asteroids were known to have low-albedo (not reflect as much light) and be close to "meteorite producing resonances".[6] Chrondrites are the most common type of meteor found on Earth, accounting for over 80% of all meteors.[7] They are named for the tiny spherical silicate particles that are found inside them (those particles are called chondrules).[7]
References
- ^ a b c d e "335 Roberta", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 11 May 2016
- ^ a b Yang, Bin; Jewitt, David (September 2010), "Identification of Magnetite in B-type Asteroids", The Astronomical Journal, 140 (3): 692–698, arXiv:1006.5110, Bibcode:2010AJ....140..692Y, doi:10.1088/0004-6256/140/3/692
- ^ "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 7 April 2013.
- ^ Kutter, A. (December 1957). "Nachruf auf Anton Staus (Obituary)". Mitteilungen der Astronomischen Gesellschaft (in German). 9: 5. Bibcode:1958MitAG...9....5K. Retrieved 6 July 2016.
- ^ Warner, Brian D.; et al. (December 2007), "Lightcurve Analysis of 335 Roberta", The Minor Planet Bulletin, vol. 34, no. 4, p. 99, Bibcode:2007MPBu...34...99W.
- ^ a b Lunar and planetary science: abstracts of papers submitted to the ... Lunar and Planetary Science Conference, Volume 27, Part 1 - Lunar and Planetary Institute, Jan 1, 1996
- ^ a b ASU - Chondrites
External links
- Lightcurve plot of 335 Roberta, Palmer Divide Observatory, B. D. Warner (2007)
- Asteroid Lightcurve Database (LCDB), query form (info)
- 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
- 335 Roberta at AstDyS-2, Asteroids—Dynamic Site
- 335 Roberta at the JPL Small-Body Database
