Astronomy:234 Barbara
| 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 | |
| Minor planet category | Main belt |
| Orbital characteristics[1] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 131.26 yr (47944 d) |
| |{{{apsis}}}|helion}} | 2.97153 astronomical unit|AU (444.535 Gm) |
| |{{{apsis}}}|helion}} | 1.79939 AU (269.185 Gm) |
| 2.38546 AU (356.860 Gm) | |
| Eccentricity | 0.24569 |
| Orbital period | 3.68 yr (1345.7 d) |
| Average Orbital speed | 19.28 km/s |
| Mean anomaly | 16.9454° |
| Mean motion | 0° 16m 3.05s / day |
| Inclination | 15.3746° |
| Longitude of ascending node | 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] |
| Rotation period | 26.4744 h (1.10310 d) |
| Geometric albedo | 0.2276±0.011 |
| S | |
| Absolute magnitude (H) | 9.02 |
Barbara (minor planet designation: 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 astronomical unit|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]
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
- ↑ 1.0 1.1 Yeomans, Donald K., "234 Barbara", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=234, retrieved 12 May 2016.
- ↑ 2.0 2.1 2.2 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73: 98–118, doi:10.1016/j.pss.2012.03.009, Bibcode: 2012P&SS...73...98C. See Table 1.
- ↑ Schmadel, Lutz (5 August 2003). Dictionary of Minor Planet Names. Springer Science & Business Media. ISBN 9783540002383. https://books.google.com/books?id=VoJ5nUyIzCsC&dq=%22234+Barbara%22+named+for&pg=PA36.
- ↑ Paluzíe-Borrell, Antonio (11 July 1963). "The Names of the Minor Planets and Their Meanings". J. Meeus, Kesselberg Sterrenwacht. https://books.google.com/books?id=jfmyAAAAIAAJ&q=%22234+Barbara%22+%22saint+barbara%22.
- ↑ 5.0 5.1 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, doi:10.1093/mnras/stv229, Bibcode: 2015MNRAS.448.3382T.
- ↑ Gil-Hutton, R. et al. (April 2008), "New cases of unusual polarimetric behavior in asteroids", Astronomy and Astrophysics 482 (1): 309–314, doi:10.1051/0004-6361:20078965, Bibcode: 2008A&A...482..309G.
- ↑ 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, doi:10.1016/j.icarus.2017.12.026, Bibcode: 2018Icar..304...31D
- ↑ "Powerful New Technique to Measure Asteroids' Sizes and Shapes". Archived from the original on 22 December 2015. https://web.archive.org/web/20151222151624/https://www.eso.org/public/news/eso0904/. Retrieved 19 December 2015.
External links
- 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
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