View source for 907 Rhoda

{{Short description|Main-belt asteroid}}
{{Use dmy dates|date=February 2020}}
{{Infobox planet
| minorplanet     = yes
| name            = 907 Rhoda
| background      = #D6D6D6
| image           =
| image_size      =
| caption         =
| discovery_ref   = &thinsp;<ref name="MPC-object" />
| discoverer      = [[Max Wolf|M. F. Wolf]]
| discovery_site  = [[Heidelberg-Königstuhl State Observatory|Heidelberg Obs.]]
| discovered      = 12 November 1918
| mpc_name        = (907) Rhoda
| alt_names       = A918 VA{{·}}A901 BA<br />A913 SC{{·}}1918 EU<br />1913 SC{{·}}1901 BA
| pronounced      = {{IPAc-en|'|r|oʊ|d|ə}}<ref>Noah Webster (1884) ''A Practical Dictionary of the English Language''</ref>
| named_after     = Rhoda Barnard<br />{{small|(wife of [[E. E. Barnard]])}}<ref name="springer" />
| mp_category     = {{nowrap|[[main-belt]]&thinsp;<ref name="MPC-object" /><ref name="jpldata" />{{·}}{{small|([[Kirkwood gap|middle]])}}}}<br />[[Background asteroid|background]]&thinsp;<ref name="AstDys-object" /><ref name="Ferret" />
| orbit_ref       = &thinsp;<ref name="jpldata" />
| epoch           = 31 May 2020 ([[Julian day|JD]] 2459000.5)
| uncertainty     = 0
| observation_arc = 118.67 [[Julian year (astronomy)|yr]] (43,343 d)
| aphelion        = 3.2553 [[Astronomical unit|AU]]
| perihelion      = 2.3468 AU
| semimajor       = 2.8010 AU
| eccentricity    = 0.1622
| period          = 4.69 yr (1,712 d)
| mean_anomaly    = 183.55[[Degree (angle)|°]]
| mean_motion     = {{Deg2DMS|0.2102|sup=ms}} / day
| inclination     = 19.525°
| asc_node        = 42.980°
| arg_peri        = 88.326°
| mean_diameter   = {{plainlist|
* {{val|62.73|1.7|ul=km}}<ref name="SIMPS" />
* {{val|75.22|0.83|u=km}}<ref name="AKARI" />
* {{val|82.660|0.340|u=km}}<ref name="Masiero-2014" />}}
| rotation        = {{val|22.44|0.02|ul=h}}<ref name="Warner-2004d" />{{efn|name=lightcurve-plot-Warner}}
| albedo          = {{plainlist|
* {{val|0.032|0.005}}<ref name="Masiero-2014" />
* {{val|0.040|0.001}}<ref name="AKARI" />
* {{val|0.0560|0.003}}<ref name="SIMPS" />}}
| spectral_type   = {{plainlist|
* [[Tholen classification|Tholen]] {{=}} [[C-type asteroid|C]]&thinsp;<ref name="jpldata" />
* [[SMASS classification|SMASS]] {{=}} [[X-type asteroid|X]][[K-type asteroid|k]]&thinsp;<ref name="jpldata" />
* [[C-type asteroid|C]]0 {{small|(Barucci)}}<ref name="Ferret" />
* [[Asteroid color indices|B–V]] {{=}} {{val|0.709|0.020}}<ref name="jpldata" />
* [[Asteroid color indices|U–B]] {{=}} {{val|0.269|0.029}}<ref name="jpldata" />}}
| abs_magnitude   = 9.7<ref name="MPC-object" /><ref name="jpldata" />
}}
'''907 Rhoda''' is a large [[background asteroid]] from the central region of the [[asteroid belt]], that measures approximately {{convert|75|km|mi|abbr=off|sigfig=2|sp=us}} in diameter. It was discovered on 12 November 1918, by astronomer [[Max Wolf]] at the [[Heidelberg Observatory]] in southwest Germany.<ref name="MPC-object" /> The dark [[C-type asteroid|C]]/[[X-type asteroid]] has a long [[rotation period]] of 22.4 hours and is likely spherical in shape. It was named after Rhoda Barnard, wife of American astronomer [[Edward Emerson Barnard]] (1857–1923).<ref name="springer" />
== Orbit and classification ==
''Rhoda'' is a non-[[Asteroid family|family]] asteroid of the main belt's [[Background asteroid|background population]] when applying the [[hierarchical clustering method]] to its [[proper orbital elements]].<ref name="AstDys-object" /><ref name="Ferret" /> It orbits the Sun in the [[Kirkwood gap|central]] asteroid belt at a distance of 2.3–3.3&nbsp;[[Astronomical unit|AU]] once every 4 years and 8 months (1,712 days; [[semi-major axis]] of 2.8&nbsp;AU). Its orbit has an [[orbital eccentricity|eccentricity]] of 0.16 and an [[orbital inclination|inclination]] of 20[[Degree (angle)|°]] with respect to the [[ecliptic]].<ref name="jpldata" /> The body's [[observation arc]] begins with its first observation as {{mp|A901 BA}} ({{mp|1901 BA}}) at the [[Heidelberg-Königstuhl State Observatory]] on 18 January 1901, where it was officially discovered almost 18 years later on 12 November 1918.<ref name="MPC-object" />
== Naming ==
This [[minor planet]] was named after Rhoda Barnard (née Calvert), wife of the American astronomer [[Edward Emerson Barnard]] (1857–1923), who was himself honored with the asteroid [[819 Barnardiana]]. The official naming was published in the journal ''[[Astronomische Nachrichten]]'' in 1922 ([[Astronomische Nachrichten|AN]] 215, 471). The {{MoMP|907|naming}} was also mentioned in ''[[The Names of the Minor Planets]]'' by [[Paul Herget]] in 1955 ({{small|[[Herget's discovery circumstances|H 88]]}}).<ref name="springer" />
== Physical characteristics ==
In the [[Tholen classification]], ''Rhoda'' is a common, carbonaceous [[C-type asteroid]], while in the Bus–Binzel [[SMASS classification]] it is a Xk-subtype, which transitions from the [[X-type asteroid|X-type]] to the uncommon [[K-type asteroid]]s.<ref name="jpldata" /> In the Barucci-taxonomy, which classified a total of 438 asteroids in 1987, ''Rhoda'' is a C0-type.<ref name="Ferret" />
=== Rotation period ===
In April 2004, a rotational [[lightcurve]] of ''Rhoda'' was obtained from [[Photometry (astronomy)|photometric]] observations by [[Brian D. Warner|Brian Warner]] at the [[Palmer Divide Observatory]] {{Obscode|716}} in Colorado. Lightcurve analysis gave a [[rotation period]] of {{val|22.44|0.02}} hours with a low brightness variation of {{val|0.16|0.02}} [[Magnitude (astronomy)|magnitude]], indicative of a non-elongated, spherical shape ({{small|[[LCDB quality code|U=3−]]}}).<ref name="Warner-2004d" />{{efn|name=lightcurve-plot-Warner}} Other period determinations were made by Marciniak as well as by Raphaël Nicollerat and [[Raoul Behrend]], giving a low-amplitude lightcurve with a period of {{val|22.46|0.01}} and {{val|22.4|0.5}} hours, respectively ({{small|[[LCDB quality code|U=2/1]]}}).<ref name="lcdb" /><ref name="geneva-obs" />
=== Diameter and albedo ===
According to the survey carried out by the Infrared Astronomical Satellite [[IRAS]], the Japanese [[Akari (satellite)|Akari satellite]], and the [[NEOWISE]] mission of NASA's [[Wide-field Infrared Survey Explorer]] (WISE), ''Rhoda'' measures ({{val|62.73|1.7}}), ({{val|75.22|0.83}}) and ({{val|82.660|0.340}}) kilometers in diameter and its surface has an [[astronomical albedo|albedo]] of ({{val|0.0560|0.003}}), ({{val|0.040|0.001}}) and ({{val|0.032|0.005}}), respectively.<ref name="SIMPS" /><ref name="AKARI" /><ref name="Masiero-2014" /> The ''Collaborative Asteroid Lightcurve Link'' adopts the results obtained by IRAS, that is, an albedo of 0.0560 and calculates a diameter of 62.73 kilometers based on an [[absolute magnitude]] of 10.74.<ref name="lcdb" /> Alternative mean-diameter measurements published by the WISE team include in ascending order ({{val|67.246|26.594|u=km}}), ({{val|84.062|30.075|u=km}}), ({{val|91.045|2.093|u=km}}) and ({{val|95.22|22.26|u=km}}) and albedos of ({{val|0.0266|0.0058}}), ({{val|0.03|0.02}}), ({{val|0.031|0.015}}) and ({{val|0.044|0.035}}).<ref name="Ferret" /><ref name="lcdb" /> An [[asteroid occultation]], observed on 23 March 2009, gave a best-fit ellipse dimension of 63.0&thinsp;×&thinsp;63.0 kilometers.<ref name="Ferret" /> These timed observations are taken when the asteroid passes in front of a distant star.<ref name="Ferret" />
== Notes ==
{{notelist|refs=
{{efn|name=lightcurve-plot-Warner|1=[http://www.minorplanetobserver.com/pdolc/A907_2004.HTM Lightcurve plot of (907) Rhoda], Palmer Divide Observatory, [[Brian D. Warner|B. D. Warner]] (2004). Rotation period {{val|22.44|0.02}} hours with a brightness amplitude of {{val|0.16|0.02}} mag. Quality code is 3. Summary figures at the [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=907 LCDB].}}
}} <!-- end of notelist -->
== References ==
{{reflist|30em|refs=
<ref name="jpldata">{{cite web
|type       = 2019-09-19 last obs.
|title      = JPL Small-Body Database Browser: 907 Rhoda (A918 VA)
|url        = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000907
|publisher  = [[Jet Propulsion Laboratory]]
|access-date = 24 February 2020}}</ref>
<ref name="springer">{{cite book
|title      = Dictionary of Minor Planet Names
|last       = Schmadel | first = Lutz D.
|publisher  = Springer Berlin Heidelberg
|chapter    = (907) Rhoda
|page       = 81
|date       = 2007
|doi        = 10.1007/978-3-540-29925-7_908
|isbn       = 978-3-540-00238-3}}</ref>
<ref name="MPC-object">{{cite web
|title      = 907 Rhoda (A918 VA)
|work       = Minor Planet Center
|url        = https://www.minorplanetcenter.net/db_search/show_object?object_id=907
|access-date = 24 February 2020}}</ref>
<ref name="geneva-obs">{{cite web
|title      = Asteroids and comets rotation curves – (907) Rhoda
|last       = Behrend |first = Raoul
|publisher  = [[Geneva Observatory]]
|url        = http://obswww.unige.ch/~behrend/page3cou.html#000907
|access-date = 24 February 2020}}</ref>
<ref name="Masiero-2014">{{cite journal
|display-authors = 6
|first1     = Joseph R. |last1 = Masiero
|first2     = T. |last2 = Grav
|first3     = A. K. |last3 = Mainzer
|first4     = C. R. |last4 = Nugent
|first5     = J. M. |last5 = Bauer
|first6     = R. |last6 = Stevenson
|first7     = S. |last7 = Sonnett
|date       = August 2014
|title      = Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos
|journal    = The Astrophysical Journal
|volume     = 791
|issue      = 2
|page       = 11
|bibcode    = 2014ApJ...791..121M
|doi        = 10.1088/0004-637X/791/2/121
|arxiv      = 1406.6645}}</ref>
<ref name="AKARI">{{cite journal
|display-authors = 6
|first1     = Fumihiko |last1 = Usui
|first2     = Daisuke |last2 = Kuroda
|first3     = Thomas G. |last3 = Müller
|first4     = Sunao |last4 = Hasegawa
|first5     = Masateru |last5 = Ishiguro
|first6     = Takafumi |last6 = Ootsubo
|first7     = Daisuke |last7 = Ishihara
|first8     = Hirokazu |last8 = Kataza
|first9     = Satoshi |last9 = Takita
|first10    = Shinki |last10 = Oyabu
|first11    = Munetaka |last11 = Ueno
|first12    = Hideo |last12 = Matsuhara
|first13    = Takashi |last13 = Onaka
|date       = October 2011
|title      = Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey
|journal    = Publications of the Astronomical Society of Japan
|volume     = 63
|issue      = 5
|pages      = 1117–1138
|bibcode    = 2011PASJ...63.1117U
|doi        = 10.1093/pasj/63.5.1117
|doi-access=
}} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-5?-source=J/PASJ/63/1117/acua_v1&Num=907 online], [https://core.ac.uk/download/pdf/43545172.pdf AcuA catalog p. 153])</ref>
<ref name="SIMPS">{{cite journal
|first1     = E. F. |last1 = Tedesco
|first2     = P. V. |last2 = Noah
|first3     = M. |last3 = Noah
|first4     = S. D. |last4 = Price
|date       = October 2004
|title      = IRAS Minor Planet Survey V6.0
|url        = https://sbnarchive.psi.edu/pds3/iras/IRAS_A_FPA_3_RDR_IMPS_V6_0/data/diamalb.tab
|journal    = NASA Planetary Data System
|volume     = 12
|pages      = IRAS-A-FPA-3-RDR-IMPS-V6.0
|bibcode    = 2004PDSS...12.....T
|access-date = 24 February 2020}}</ref>
<ref name="lcdb">{{cite web
|title      = LCDB Data for (907) Rhoda
|publisher  = Asteroid Lightcurve Database (LCDB)
|url        = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=907
|access-date = 24 February 2020}}</ref>
<ref name="Warner-2004d">{{cite journal
|last1      = Warner |first1 = Brian D.
|date       = December 2004
|title      = Lightcurve analysis for numbered asteroids 863, 903, 907, 928, 977, 1386 2841, and 75747
|journal    = Minor Planet Bulletin
|url        = http://www.minorplanet.info/MPB/issues/MPB_31-4.pdf
|volume     = 31
|issue      = 4
|pages      = 85–88
|bibcode    = 2004MPBu...31...85W
|issn       = 1052-8091}}</ref>
<ref name="Ferret">{{cite web
|title      = Asteroid 907 Rhoda
|work       = Small Bodies Data Ferret
|url        = https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=907+Rhoda
|access-date = 24 February 2020}}</ref>
<ref name="AstDys-object">{{cite web
|title      = Asteroid 907 Rhoda – Proper Elements
|publisher  = AstDyS-2, Asteroids – Dynamic Site
|url        = https://newton.spacedys.com/astdys/index.php?pc=1.1.6&n=907
|access-date= 24 February 2020}}</ref>
}} <!-- end of reflist -->
== External links ==
* [http://www.minorplanet.info/PHP/OneAsteroidInfo.php Lightcurve Database Query] (LCDB), at ''www.minorplanet.info''
* [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books
* [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR] – ''Geneva Observatory'', [[Raoul Behrend]]
* [http://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center
* {{AstDys|907}}
* {{JPL small body}}
{{Minor planets navigator |906 Repsolda |number=907 |908 Buda}}
{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:Rhoda}}
[[Category:Background asteroids|000907]]
[[Category:Discoveries by Max Wolf]]
[[Category:Named minor planets]]
[[Category:C-type asteroids (Tholen)|000907]]
[[Category:Xk-type asteroids (SMASS)|000907]]
[[Category:Astronomical objects discovered in 1918|19181112]]