335 Roberta

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335 Roberta
Discovered byAnton Staus
Discovery date1 September 1892
MPC designation(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 arc123.58 yr (45137 d)
Aphelion2.9014 AU (434.04 Gm)
Perihelion2.04926 AU (306.565 Gm)
2.47530 AU (370.300 Gm)
3.89 yr (1422.5 d)
18.93 km/s
0° 15m 11.095s / day
Earth MOID1.03587 AU (154.964 Gm)
Jupiter MOID2.2733 AU (340.08 Gm)
Physical characteristics
Dimensions89.07±2.0 km[1]
12.054 h (0.5023 d)
B–V = 0.624
U–B = 0.235
FP (Tholen)
B (SMASS)[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]


  1. ^ a b c d e "335 Roberta", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 11 May 2016
  2. ^ 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
  3. ^ "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 7 April 2013.
  4. ^ 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.
  5. ^ Warner, Brian D.; et al. (December 2007), "Lightcurve Analysis of 335 Roberta", The Minor Planet Bulletin, 34 (4), p. 99, Bibcode:2007MPBu...34...99W.
  6. ^ 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
  7. ^ a b ASU - Chondrites

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