View source for Astronomy:375 Ursula

{{Short description|Main-belt asteroid}}
{{Infobox planet
 | minorplanet     = yes
 | name            = 375 Ursula
 | background      = #D6D6D6
 | image           = 375Ursula-LB1.jpg
 | image_scale      =
 | caption         = ''Ursula'' imaged at [[Astronomy:Apparent magnitude|amag]] 11.4 near the star TYC 581-36-1 (magnitude 11.9). The two galaxies are about magnitude 15.
 | discovery_ref   = &thinsp;<ref name="jpldata" />
 | discoverer      = [[Biography:Auguste Charlois|A. Charlois]]
 | discovery_site  = Nice Obs.
 | discovered      = 18 September 1893
 | mpc_name        = (375) Ursula
 | pronounced      = {{IPAc-en|ˈ|ɜːr|sj|uː|l|ə}}
 | adjective       = Ursulian {{IPAc-en|ɜːr|ˈ|sj|uː|l|i|ə|n}}
 | alt_names       = 1893 AL
 | named_after     = ''unknown''<ref name="springer" />
 | mp_category     = main-belt{{·}}{{small|([[Astronomy:Kirkwood gap|outer]])}}&thinsp;<ref name="lcdb" /><br />Ursula&thinsp;<ref name="Ferret" />
 | orbit_ref       = &thinsp;<ref name="jpldata" />
 | epoch           = 4 September 2017 ([[Astronomy:Julian day|JD]] 2458000.5)
 | uncertainty     = 0
 | observation_arc = 124.06 yr (45,314 days)
 | aphelion        = 3.4544 [[Astronomy:Astronomical unit|AU]]
 | perihelion      = 2.7928 AU
 | semimajor       = 3.1236 AU
 | eccentricity    = 0.1059
 | period          = 5.52 [[Astronomy:Julian year|yr]] (2,016 days)
 | mean_anomaly    = 189.03[[Degree (angle)|°]]
 | mean_motion     = {{Deg2DMS|0.1785|sup=ms}} / day
 | inclination     = 15.943°
 | asc_node        = 336.57°
 | arg_peri        = 342.15°
 | dimensions      = {{val|189.45|54.76}} km<ref name="Nugent-2015" /><br />{{val|191.65|4.01}} km<ref name="Carry2012"/><br />{{val|193.63|2.52}} km<ref name="AKARI" /><br />{{val|215.67|54.80}} km<ref name="Nugent-2016" /><br />{{val|216|10}} km<ref name="Millis-1984" /><br />216.10 km {{small|(taken)}}<ref name="lcdb" />
 | mass            = {{val|8.45|5.26|e=18|ul=kg}}<ref name="Carry2012"/>
 | density         = {{val|2.29|1.43|u=g/cm3}}<ref name="Carry2012"/>
 | rotation        = {{val|16.78|0.01}} [[Hour|h]]<ref name="lcdb" /><br />{{val|16.83}} h<ref name="Schober-1983e" /><ref name="Schober-1987" /><br />{{val|16.899|0.001}} h<ref name="Pilcher-2017f" /><br />{{val|16.900|0.003}} h<ref name="Harris-1999a" />
 | albedo          = {{val|0.04|0.03}}<ref name="Nugent-2016" /><br />{{val|0.042|0.027}}<ref name="Nugent-2015" /><br />{{val|0.049|0.001}}<ref name="AKARI" /><br />0.0494 {{small|(derived)}}<ref name="lcdb" />
 | spectral_type   = Tholen {{=}} [[Astronomy:C-type asteroid|C]]&thinsp;<ref name="jpldata" /><br />SMASS {{=}} Xc&thinsp;<ref name="jpldata" /><br />B–V {{=}} 0.683<ref name="jpldata" /><br />U–B {{=}} 0.341<ref name="jpldata" />
 | abs_magnitude   = 7.21<ref name="lcdb" />{{·}}{{val|7.21|0.02}}<ref name="Harris-1999a" /><ref name="Pravec-2012b" />{{·}}7.45<ref name="Nugent-2016" />{{·}}7.47<ref name="jpldata" /><ref name="Nugent-2015" /><ref name="AKARI" />{{·}}{{val|7.58|0.31}}<ref name="Veres-2015" />
}}

'''Ursula''' ([[Astronomy:Minor planet designation|minor planet designation]]: '''375 Ursula'''), provisional designation {{mp|1893 AL}}, is a dark [[Astronomy:Asteroid|asteroid]] and parent body of the Ursula family from the outer regions of the [[Astronomy:Asteroid belt|asteroid belt]]. It is one of the [[Astronomy:List of exceptional asteroids#Largest by diameter|largest asteroids]] with a diameter of approximately 200 kilometers. It was discovered on 18 September 1893, by French astronomer [[Biography:Auguste Charlois|Auguste Charlois]] at Nice Observatory in France.<ref name="MPC-object" /> The [[Astronomy:Meanings of minor planet names|referent]] of the asteroids's name is unknown.<ref name="springer" />

== Orbit and classification ==

''Ursula'' is the [[Astronomy:Parent body|parent body]] of the Ursula family ({{small|[[Astronomy:FIN tbl#631|631]]}}),<ref name="Ferret" /> a large [[Astronomy:Asteroid family|family]] of [[Astronomy:C-type asteroid|C-]] and [[Astronomy:X-type asteroid|X-type asteroid]]s.<ref name="Nesvorny-2014" />{{rp|23}} It orbits the Sun in the [[Astronomy:Kirkwood gap|outer]] asteroid belt at a distance of 2.8–3.5&nbsp;[[Astronomy:Astronomical unit|AU]] once every 5 years and 6 months (2,016 days; semi-major axis of 3.12&nbsp;AU). Its orbit has an [[Astronomy:Orbital eccentricity|eccentricity]] of 0.11 and an [[Astronomy:Orbital inclination|inclination]] of 16[[Degree (angle)|°]] with respect to the [[Astronomy:Ecliptic|ecliptic]].<ref name="jpldata" /> The body's [[Astronomy:Observation arc|observation arc]] begins at Vienna Observatory in October 1893, three weeks after its official discovery observation at Nice.<ref name="MPC-object" />

== Physical characteristics ==

In the Tholen classification, ''Ursula'' is a carbonaceous [[Astronomy:C-type asteroid|C-type asteroid]], while in the SMASS taxonomy, it is a Xc-subtype that transitions to the [[Astronomy:X-type asteroid|X-type asteroid]]s.<ref name="jpldata" />

=== Rotation period ===

In January 2017, the so-far best-rated rotational [[Astronomy:Lightcurve|lightcurve]] of ''Ursula'' was obtained from photometric observations by American astronomer Frederick Pilcher at the Organ Mesa Observatory ({{small|G50}}), New Mexico. Lightcurve analysis gave a [[Rotation period|rotation period]] of 16.899 hours with a brightness amplitude of 0.11 [[Astronomy:Magnitude|magnitude]] ({{small|U=3}}).<ref name="Pilcher-2017f" />

=== Diameter and albedo ===

According to the surveys carried out by the Japanese [[Astronomy:Akari (satellite)|Akari satellite]] and the [[Astronomy:NEOWISE|NEOWISE]] mission of NASA's [[Astronomy:Wide-field Infrared Survey Explorer|Wide-field Infrared Survey Explorer]], ''Ursula'' measures between 189.45 and 215.67 kilometers in diameter and its surface has an [[Astronomy:Astronomical albedo|albedo]] between 0.04 and 0.049.<ref name="Nugent-2015" /><ref name="AKARI" /><ref name="Nugent-2016" />

Observations of an [[Astronomy:Asteroid occultation|occultation]] on 15 November 1984, produced six [[Astronomy:Chord|chords]] indicating an estimated diameter of 216±10&nbsp;km.<ref name="Millis-1984" /> The ''Collaborative Asteroid Lightcurve Link'' derives an albedo of 0.0494 and adopts a diameter of 216.1 kilometers based on an [[Astronomy:Absolute magnitude|absolute magnitude]] of 7.21.<ref name="lcdb" />

== Naming ==

Any reference of this [[Astronomy:Minor planet|minor planet]]'s name to a person or occurrence is unknown.<ref name="springer" />

=== Unknown referent ===

Among the many thousands of [[Astronomy:List of named minor planets (alphabetical)|named minor planets]], ''Ursula'' is one of only 120 for which no official naming citation has been published. All of these asteroids have low numbers between {{mp|{{MoMP|164|164 Eva}}}} and {{mp|{{MoMP|1514|1514 Ricouxa}}}} and were discovered between 1876 and the 1930s, predominantly by astronomers [[Biography:Auguste Charlois|Auguste Charlois]], [[Biography:Johann Palisa|Johann Palisa]], [[Biography:Max Wolf|Max Wolf]] and Karl Reinmuth.<ref name="DOMPN-unknown" />

==References==
{{Reflist|refs=

<ref name="Carry2012">{{Citation
  |first1    = B.
  |last1     = Carry
  |title     = Density of asteroids
  |journal      = Planetary and Space Science
  |volume    = 73
  |issue = 1
 |pages      = 98–118
  |date=December 2012
  |doi       = 10.1016/j.pss.2012.03.009
  |bibcode   = 2012P&SS...73...98C
  |postscript= .
  |arxiv = 1203.4336 }} See Table 1.</ref>

<ref name="jpldata">{{cite web
  |type       = 2017-10-30 last obs.
  |title      = JPL Small-Body Database Browser: 375 Ursula (1893 AL)
  |url        = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000375
  |archive-url = https://web.archive.org/web/20210501102304/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000375
  |url-status = dead
  |archive-date = 1 May 2021
  |publisher  = [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]]
  |access-date = 6 December 2017}}</ref>

<ref name="springer">{{cite book
  |last       = Schmadel | first = Lutz D.
  |title = Dictionary of Minor Planet Names |chapter = (375) Ursula |publisher  = Springer Berlin Heidelberg
  |page       = 46
  |date       = 2007
  |isbn       = 978-3-540-00238-3
  |doi = 10.1007/978-3-540-29925-7_376 }}</ref>

<ref name="DOMPN-unknown">{{cite book
  |title      = Dictionary of Minor Planet Names – Fifth Revised and Enlarged revision
  |chapter    = Appendix 11 – Minor Planet Names with Unknown Meaning
  |last       = Schmadel | first = Lutz D.
  |publisher  = Springer Berlin Heidelberg
  |pages      = 927–929
  |date       = 2007
  |isbn       = 978-3-540-00238-3

<ref name="MPC-object">{{cite web
  |title      = 375 Ursula (1893 AL)
  |work       = Minor Planet Center
  |url        = https://www.minorplanetcenter.net/db_search/show_object?object_id=375
  |access-date = 6 December 2017}}</ref>

<ref name="Ferret">{{cite web
  |title      = Asteroid 375 Ursula – Nesvorny HCM Asteroid Families V3.0
  |work       = Small Bodies Data Ferret
  |url        = https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=375+Ursula
  |access-date = 24 October 2019}}</ref>

<ref name="Nesvorny-2014">{{Cite book
  |first1     = D. |last1 = Nesvorný
  |first2     = M. |last2 = Broz
  |first3     = V. |last3 = Carruba
  |date       = December 2014
  |chapter      = Identification and Dynamical Properties of Asteroid Families
  |title    = Asteroids IV
  |pages      = 297–321
  |bibcode    = 2015aste.book..297N
  |doi        = 10.2458/azu_uapress_9780816532131-ch016
  |arxiv      = 1502.01628
  |isbn = 9780816532131
 }}</ref>

<ref name="lcdb">{{cite web
  |title      = LCDB Data for (375) Ursula
  |publisher  = Asteroid Lightcurve Database (LCDB)
  |url        = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=375%7CUrsula
  |access-date = 6 December 2017}}</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= free
  }} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-5?-source=J/PASJ/63/1117/acua_v1&Num=375 online], [https://core.ac.uk/download/pdf/43545172.pdf AcuA catalog p. 153])</ref>

<ref name="Millis-1984">{{Cite journal
  |first1     = R. L. |last1 = Millis
  |first2     = L. H. |last2 = Wasserman
  |first3     = E. |last3 = Bowell
  |first4     = O. G. |last4 = Franz
  |first5     = A. |last5 = Klemola
  |first6     = D. W. |last6 = Dunham
  |date       = April 1984
  |title      = The diameter of 375 URSULA from its occultation of AG + 39 deg 303
  |journal    = Astronomical Journal
  |volume = 89
 |pages      = 592–596
  |issn       = 0004-6256
  |bibcode    = 1984AJ.....89..592M
  |doi        = 10.1086/113553
  |doi-access= free
  }}</ref>

<ref name="Nugent-2016">{{cite journal
  |display-authors = 6
  |first1     = C. R. |last1 = Nugent
  |first2     = A. |last2 = Mainzer
  |first3     = J. |last3 = Bauer
  |first4     = R. M. |last4 = Cutri
  |first5     = E. A. |last5 = Kramer
  |first6     = T. |last6 = Grav
  |first7     = J. |last7 = Masiero
  |first8     = S. |last8 = Sonnett
  |first9     = E. L. |last9 = Wright
  |date       = September 2016
  |title      = NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos
  |journal    = The Astronomical Journal
  |volume     = 152
  |issue      = 3
  |page       = 12
  |bibcode    = 2016AJ....152...63N
  |doi        = 10.3847/0004-6256/152/3/63
  |arxiv      = 1606.08923
  |doi-access = free }}</ref>

<ref name="Nugent-2015">{{cite journal
  |display-authors = 6
  |first1     = C. R. |last1 = Nugent
  |first2     = A. |last2 = Mainzer
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  |first9     = R. |last9 = Stevenson
  |first10    = E. L. |last10 = Wright
  |date       = December 2015
  |title      = NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos
  |journal    = The Astrophysical Journal
  |volume     = 814
  |issue      = 2
  |page       = 13
  |bibcode    = 2015ApJ...814..117N
  |doi        = 10.1088/0004-637X/814/2/117
  |arxiv      = 1509.02522
  }}</ref>

<ref name="Schober-1983e">{{Cite journal
  |author     = Schober, H. J.
  |date       = December 1982
  |title      = Rotations of all asteroids larger than 200 KM
  |journal    = IN: Asteroids
  |pages      = 21–26.ResearchsupportedbytheSteiermaerkischerWissenschafts–undForschungslandesfonds;FondszurFoerderungderWissenschaftlichenForschung
  |bibcode    = 1983acm..proc...21S
  }}</ref>

<ref name="Schober-1987">{{Cite journal
  |author     = Schober, H. J.
  |date       = September 1987
  |title      = Rotation and variability of the large C-type asteroid 375 URSULA
  |journal    = Astronomy and Astrophysics
  |volume = 183
 |issue = 1
 |pages      = 151–155
  |issn       = 0004-6361
  |bibcode    = 1987A&A...183..151S
  }}</ref>

<ref name="Pilcher-2017f">{{Cite journal
  |author     = Pilcher, Frederick
  |date       = July 2017
  |title      = Rotation Period Determinations for 49 Pales, 96 Aegle, 106 Dione 375 Ursula, and 576 Emanuela
  |journal    = The Minor Planet Bulletin
  |volume     = 44
  |issue      = 3
  |pages      = 249–251
  |issn       = 1052-8091
  |bibcode    = 2017MPBu...44..249P
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<ref name="Harris-1999a">{{Cite journal
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<ref name="Pravec-2012b">{{Cite journal
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<ref name="Veres-2015">{{cite journal
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}} <!-- end of reflist -->

== External links ==
* [https://web.archive.org/web/20081014165709/http://occsec.wellington.net.nz/planet/2008/results/20080527_Ursula_Rep.htm Occultation of UCAC2 12060928 by 375 Ursula], Royal Astronomical Society of New Zealand, 27 May 2008
* [http://obswww.unige.ch/~behrend/page2cou.html#000375 (375) Ursula], Asteroids and comets rotation curves, Raymond Poncy and Pierre Antonini (2006), Geneva Observatory
* [http://www.minorplanet.info/PHP/lcdbsummaryquery.php Asteroid Lightcurve Database (LCDB)], query form ([http://www.minorplanet.info/lightcurvedatabase.html info] {{Webarchive|url=https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html |date=16 December 2017 }})
* [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books
* [https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center
* {{AstDys|375}}
* {{JPL small body}}

{{Large asteroids}}
{{Small Solar System bodies}}

{{DEFAULTSORT:Ursula}}
[[Category:Ursula asteroids|000375]]
[[Category:Named minor planets]]
[[Category:C-type asteroids (Tholen)|000375]]

{{Sourceattribution|375 Ursula}}