{{Short description|Main-belt asteroid}} {{Use dmy dates|date=October 2019}} {{Infobox planet | minorplanet = yes | background = #D6D6D6 | name = 189 Phthia | symbol = |image=000189-asteroid shape model (189) Phthia.png |caption= 3D convex shape model of 189 Phthia | discovery_ref = <ref name="IAU_MPC"/> | discoverer = C. H. F. Peters | discovered = 9 September 1878 | discovery_site = Clinton, New York | mpc_name = (189) Phthia | mp_category = main-belt | alt_names = A878 RA | pronounced = {{IPAc-en|'|θ|aɪ|.|ə}}<ref>Noah Webster (1884) ''A Practical Dictionary of the English Language''</ref> | orbit_ref = <ref name="JPL"/><ref name="lowell">{{Cite web |url=http://ftp.lowell.edu/pub/elgb/astorb.html |website=astorb |title=The Asteroid Orbital Elements Database |publisher=Lowell Observatory }}</ref> | epoch = 31 July 2016 (JD 2457600.5) | aphelion = {{Convert|2.5415|AU|Gm|abbr=on|lk=on}} | perihelion = {{Convert|2.3597|AU|Gm|abbr=on}} | semimajor = {{Convert|2.4506|AU|Gm|abbr=on}} | eccentricity = 0.037105 | period = 3.84 yr (1401.2 d) | inclination = 5.1774° | dimensions = {{val|37.66|2.0|ul=km}}<ref name="JPL"/><br />40.91 ± 1.36 km<ref name="Carry2012"/> | mass = {{nowrap|(3.84 ± 0.81) × 10<sup>16</sup> kg<ref name="Carry2012"/>}} | density = 1.07 ± 0.25 g/cm<sup>3</sup><ref name="Carry2012"/> | spectral_type = S<ref name="Pravec2012"/> (Tholen) | albedo = {{val|0.2310|0.027}}<ref name="JPL"/><br />0.1566 ± 0.0349<ref name="Pravec2012"/> | abs_magnitude = 9.33,<ref name="JPL"/> 9.60<ref name="Pravec2012"/> | rotation = {{Convert|22.346|h|d|abbr=on|lk=on}}<ref name="JPL"/><ref name="Pilcher2009"/> | asc_node = 203.42° | arg_peri = 168.03° | mean_anomaly = 336.98° | mean_motion = {{Deg2DMS|0.25692|sup=ms}} / day | observation_arc = 136.18 yr (49739 d) | uncertainty = 0 }}
'''189 Phthia''' is a bright-coloured, rocky main belt asteroid that was discovered by German-American astronomer Christian Heinrich Friedrich Peters on September 9, 1878,<ref name="IAU_MPC"/> in Clinton, New York, and named after Phthia, a region of ancient Greece.
Photometric observations of this asteroid at the Organ Mesa Observatory in Las Cruces, New Mexico, during 2008 gave a light curve with a period of 22.346 ± 0.001 hours and a brightness variation of 0.26 ± 0.02 in magnitude.<ref name="Pilcher2009"/>
==References== {{Reflist|refs=
<ref name="IAU_MPC">{{Citation | title = Numbered Minor Planets 1–5000 | work = Discovery Circumstances | publisher = IAU Minor Planet center | url = https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html | accessdate= 2013-04-07 | postscript= .}}</ref>
<ref name="JPL">{{Citation | first1 = Donald K. | last1 = Yeomans | title = 189 Phthia | work = JPL Small-Body Database Browser | publisher = NASA Jet Propulsion Laboratory | url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=189 | accessdate= 12 May 2016 | postscript= .}}</ref>
<ref name="Carry2012">{{Citation | first1 = B. | last1 = Carry | title = Density of asteroids | work = Planetary and Space Science | volume = 73 | 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="Pravec2012">{{Citation | last1 = Pravec | first1 = P. | last2 = Harris | first2 = A. W. | last3 = Kusnirak | first3 = P. | last4 = Galad | first4 = A. | last5 = Hornoch | first5 = K. | display-authors = 1 | title = Absolute Magnitudes of Asteroids and a Revision of Asteroid Albedo Estimates from WISE Thermal Observations | work = Asteroids, Comets, Meteors 2012, Proceedings of the conference held May 16–20, 2012 in Niigata, Japan | issue = 1667 |date=May 2012 | bibcode = 2012LPICo1667.6089P | postscript= .}} See Table 4.</ref>
<ref name="Pilcher2009">{{Citation | last1 = Pilcher | first1 = Frederick | title = Period Determinations for 33 Polyhymnia, 38 Leda, 50 Virginia, 189 Phthia, and 290 Bruna | work = The Minor Planet Bulletin | volume = 36 | issue = 1 | pages = 25–27 |date=January 2009 | bibcode = 2009MPBu...36...25P | postscript= .}}</ref>
}} <!-- end of reflist -->
==External links== * {{AstDys|189}} * {{JPL small body}}
{{Minor planets navigator |188 Menippe |number=189 |190 Ismene}} {{Small Solar System bodies}} {{Authority control}}
{{DEFAULTSORT:000189}} Category:Background asteroids Phthia Phthia Category:S-type asteroids (Tholen) Category:Sa-type asteroids (SMASS) 18780909
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