234 Barbara
{{Short description|Main-belt asteroid}}
{{Use dmy dates|date=October 2019}}
{{Infobox planet
| minorplanet=yes
| background=#D6D6D6
| name=234 Barbara
| discoverer=C. H. F. Peters
| discovered=12 August 1883
| mpc_name=(234) Barbara
|named_after=Saint Barbara?
| alt_names=A883 PA, {{mp|1942 RL|1}}
1953 RE,1975 XP
| mp_category=Main belt
| epoch=31 July 2016 (JD 2457600.5)
| semimajor={{Convert|2.38546|AU|Gm|abbr=on}}
| perihelion={{Convert|1.79939|AU|Gm|abbr=on}}
| aphelion={{Convert|2.97153|AU|Gm|abbr=on|lk=on}}
| eccentricity=0.24569
| inclination=15.3746°
| asc_node=144.553°
| arg_peri=192.344°
| mean_anomaly=16.9454°
| avg_speed=19.28 km/s
| dimensions={{val|43.75|1.0|ul=km}}
45.62 ± 1.93 km
| mass={{nowrap|(0.44 ± 1.45) × 1018 kg}}
| density=
| rotation={{Convert|26.4744|h|d|abbr=on|lk=on}}
| spectral_type=S
| abs_magnitude=9.02
| albedo={{val|0.2276|0.011}}
| single_temperature=
| mean_motion={{Deg2DMS|0.267514|sup=ms}} / day
| observation_arc=131.26 yr (47944 d)
| uncertainty=0
}}
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 {{Val|2.385|ul=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. 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.{{Cite book|url=https://books.google.com/books?id=VoJ5nUyIzCsC&dq=%22234+Barbara%22+named+for&pg=PA36|title=Dictionary of Minor Planet Names|first=Lutz|last=Schmadel|date=5 August 2003|publisher=Springer Science & Business Media|isbn=9783540002383 |via=Google Books}}{{Cite web|url=https://books.google.com/books?id=jfmyAAAAIAAJ&q=%22234+Barbara%22+%22saint+barbara%22|title=The Names of the Minor Planets and Their Meanings|first=Antonio|last=Paluzíe-Borrell|date=11 July 1963|publisher=J. Meeus, Kesselberg Sterrenwacht|via=Google Books}}
Observations of light curves and stellar occultations suggest the surface exhibits large concave areas. 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. 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.
Observations made in 2009 with ESO's Very Large Telescope Interferometer (VLTI) suggested that 234 Barbara may be a binary asteroid,{{cite web|title=Powerful New Technique to Measure Asteroids' Sizes and Shapes |url=https://www.eso.org/public/news/eso0904/ |website=European Southern Observatory |accessdate=19 December 2015 |archiveurl=https://web.archive.org/web/20151222151624/https://www.eso.org/public/news/eso0904/ |archivedate=22 December 2015 |url-status=live }} although a paper published in 2015 states that "the VLTI observations can be explained without the presence of a large satellite".
References
{{Reflist|refs=
| first1 = Donald K.
| last1 = Yeomans
| title = 234 Barbara
| work = JPL Small-Body Database Browser
| publisher = NASA Jet Propulsion Laboratory
| url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=234
| accessdate= 12 May 2016
| postscript= .
}}
| first1 = B.
| last1 = Carry
| title = Density of asteroids
| journal = Planetary and Space Science
| volume = 73
| pages = 98–118
|date=December 2012
| issue = 1
| doi = 10.1016/j.pss.2012.03.009
| bibcode = 2012P&SS...73...98C
| postscript= .
|arxiv = 1203.4336 | s2cid = 119226456
}} See Table 1.
| last1 = Gil-Hutton
| first1 = R.
| last2 = Mesa
| first2 = V.
| last3 = Cellino
| first3 = A.
| last4 = Bendjoya
| first4 = P.
| last5 = Peñaloza
| first5 = L.
| last6 = Lovos
| first6 = F.
| display-authors = 1
| title = New cases of unusual polarimetric behavior in asteroids
| journal = Astronomy and Astrophysics
| volume = 482
| issue = 1
| pages = 309–314
|date=April 2008
| doi = 10.1051/0004-6361:20078965
| bibcode = 2008A&A...482..309G
| postscript= .
| doi-access= free
}}
| title=New polarimetric and spectroscopic evidence of anomalous enrichment in spinel-bearing calcium-aluminium-rich inclusions among L-type asteroids
| display-authors=1
| last1=Devogèle | first1=M.
| last2=Tanga | first2=P.
| last3=Cellino | first3=A.
| last4=Bendjoya | first4=Ph.
| last5=Rivet | first5=J. -P.
| last6=Surdej | first6=J.
| last7=Vernet | first7=D.
| last8=Sunshine | first8=J. M.
| last9=Bus | first9=S. J.
| last10=Abe | first10=L.
| last11=Bagnulo | first11=S.
| last12=Borisov | first12=G.
| last13=Campins | first13=H.
| last14=Carry | first14=B.
| last15=Licandro | first15=J.
| last16=McLean | first16=W.
| last17=Pinilla-Alonso | first17=N.
| journal=Icarus
| volume=304
| pages=31–57
| date=April 2018
| arxiv=1802.06975
| bibcode=2018Icar..304...31D
| doi=10.1016/j.icarus.2017.12.026
| s2cid=54992862
}}
{{citation | display-authors=1
| title=The non-convex shape of (234) Barbara, the first Barbarian*
| last1=Tanga | first1=P.
| last2=Carry | first2=B.
| last3=Colas | first3=F.
| last4=Delbo | first4=M.
| last5=Matter | first5=A.
| last6=Hanuš | first6=J.
| last7=Alí Lagoa | first7=V.
| last8=Andrei | first8=A. H.
| last9=Assafin | first9=M.
| last10=Audejean | first10=M.
| last11=Behrend | first11=R.
| last12=Camargo | first12=J. I. B.
| last13=Carbognani | first13=A.
| last14=Cedrés Reyes | first14=M.
| last15=Conjat | first15=M.
| last16=Cornero | first16=N.
| last17=Coward | first17=D.
| last18=Crippa | first18=R.
| last19=de Ferra Fantin
| first19=E. | last20=Devogéle | first20=M.
| last21=Dubos | first21=G.
| last22=Frappa | first22=E.
| last23=Gillon | first23=M.
| last24=Hamanowa | first24=H.
| last25=Jehin | first25=E.
| last26=Klotz | first26=A.
| last27=Kryszczyńska | first27=A.
| last28=Lecacheux | first28=J.
| last29=Leroy | first29=A.
| last30=Manfroid | first30=J.
| last31=Manzini | first31=F.
| last32=Maquet | first32=L.
| last33=Morelle | first33=E.
| last34=Mottola | first34=S.
| last35=Polińska | first35=M.
| last36=Roy | first36=R.
| last37=Todd | first37=M.
| last38=Vachier | first38=F.
| last39=Vera Hernández | first39=C.
| last40=Wiggins | first40=P.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=448
| issue=4
| pages=3382–3390
| date=April 2015
| doi=10.1093/mnras/stv229
| doi-access=free
| arxiv=1502.00460
| bibcode=2015MNRAS.448.3382T
| postscript=.
}}
}}
External links
- [http://ftp.lowell.edu/pub/elgb/astorb.html The Asteroid Orbital Elements Database]
- [http://cfa-www.harvard.edu/iau/lists/NumberedMPs.html Minor Planet Discovery Circumstances]
- [http://spiff.rit.edu/richmond/parallax/phot/LCSUMPUB.TXT Asteroid Lightcurve Data File]
- {{AstDys|234}}
- {{JPL small body}}
{{Minor planets navigator |233 Asterope |number=234 |235 Carolina}}
{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:000234}}
Category:S-type asteroids (Tholen)