234 Barbara is a main belt asteroid that was discovered by German-American astronomer Christian Heinrich Friedrich Peters on August 12, 1883, in Clinton, New York. The object is orbiting the Sun with a semimajor axis of 2.385 AU, a period of 3.68 years, and an eccentricity of 0.25. The orbital plane is inclined by 15.37° to the plane of the ecliptic. It is classified as a stony S-type asteroid based upon its spectrum. The mean diameter of this object is estimated as 45.6 km.[2] It has a rotation rate of 26.5 hours, or a little over a day. It is possibly named for Saint Barbara, patron saint of mathematicians.[3][4]
| Discovery | |
|---|---|
| Discovered by | C. H. F. Peters |
| Discovery date | 12 August 1883 |
| Designations | |
| (234) Barbara | |
Named after | Saint Barbara? |
| A883 PA, 1942 RL1 1953 RE,1975 XP | |
| Main belt | |
| Orbital characteristics[1] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 131.26 yr (47944 d) |
| Aphelion | 2.97153 AU (444.535 Gm) |
| Perihelion | 1.79939 AU (269.185 Gm) |
| 2.38546 AU (356.860 Gm) | |
| Eccentricity | 0.24569 |
| 3.68 yr (1345.7 d) | |
Average orbital speed | 19.28 km/s |
| 16.9454° | |
| 0° 16m 3.05s / day | |
| Inclination | 15.3746° |
| 144.553° | |
| 192.344° | |
| Physical characteristics | |
| Dimensions | 43.75±1.0 km[1] 45.62 ± 1.93 km[2] |
| Mass | (0.44 ± 1.45) × 1018 kg[2] |
| 26.4744 h (1.10310 d) | |
| 0.2276±0.011 | |
| S | |
| 9.02 | |
Observations of light curves and stellar occultations suggest the surface exhibits large concave areas.[5] Polarimetric study of this asteroid reveals anomalous properties that suggests the regolith consists of a mixture of low and high albedo material. This may have been caused by fragmentation of an asteroid substrate with the spectral properties of CO3/CV3 carbonaceous chondrites.[6] It is the prototype for a class of asteroids called "Barbarians" that display a strong infrared absorption band at 2μm, which is a characteristic of an FeO–enriched spinel mineral. Multiple other examples of this class have since been discovered.[7]
Observations made in 2009 with ESO's Very Large Telescope Interferometer (VLTI) suggested that 234 Barbara may be a binary asteroid,[8] although a paper published in 2015 states that "the VLTI observations can be explained without the presence of a large satellite".[5]
References
edit- ^ a b Yeomans, Donald K., "234 Barbara", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
- ^ a b c Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73 (1): 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009, S2CID 119226456. See Table 1.
- ^ Schmadel, Lutz (5 August 2003). Dictionary of Minor Planet Names. Springer Science & Business Media. ISBN 9783540002383 – via Google Books.
- ^ Paluzíe-Borrell, Antonio (11 July 1963). "The Names of the Minor Planets and Their Meanings". J. Meeus, Kesselberg Sterrenwacht – via Google Books.
- ^ a b Tanga, P.; et al. (April 2015), "The non-convex shape of (234) Barbara, the first Barbarian*", Monthly Notices of the Royal Astronomical Society, 448 (4): 3382–3390, arXiv:1502.00460, Bibcode:2015MNRAS.448.3382T, doi:10.1093/mnras/stv229.
- ^ Gil-Hutton, R.; et al. (April 2008), "New cases of unusual polarimetric behavior in asteroids", Astronomy and Astrophysics, 482 (1): 309–314, Bibcode:2008A&A...482..309G, doi:10.1051/0004-6361:20078965.
- ^ Devogèle, M.; et al. (April 2018), "New polarimetric and spectroscopic evidence of anomalous enrichment in spinel-bearing calcium-aluminium-rich inclusions among L-type asteroids", Icarus, 304: 31–57, arXiv:1802.06975, Bibcode:2018Icar..304...31D, doi:10.1016/j.icarus.2017.12.026, S2CID 54992862
- ^ "Powerful New Technique to Measure Asteroids' Sizes and Shapes". European Southern Observatory. Archived from the original on 22 December 2015. Retrieved 19 December 2015.
External links
edit- The Asteroid Orbital Elements Database
- Minor Planet Discovery Circumstances
- Asteroid Lightcurve Data File
- 234 Barbara at AstDyS-2, Asteroids—Dynamic Site
- 234 Barbara at the JPL Small-Body Database
