Editing 306 Unitas

{{Short description|Main-belt asteroid}}
{{Use dmy dates|date=September 2019}}
{{Infobox planet
 | minorplanet=yes
 | background=#D6D6D6
 | name=306 Unitas
 | image=306Unitas (Lightcurve Inversion).png
 | image_scale =
 | caption=A three-dimensional model of 306 Unitas based on its light curve
 | discoverer=[[Elia Millosevich]]
 | discovered=1 March 1891
 | mpc_name=(306) Unitas
 | alt_names=A891 EA
 | pronounced= {{IPAc-en|'|j|uː|n|ᵻ|t|æ|s}}
 | mp_category=[[Asteroid belt|Main belt]]
 | epoch=31 July 2016 ([[Julian day|JD]] 2457600.5)
 | semimajor={{Convert|2.35785|AU|Gm|abbr=on}}
 | perihelion={{Convert|2.0009|AU|Gm|abbr=on}}
 | aphelion={{Convert|2.71480|AU|Gm|abbr=on|lk=on}}
 | eccentricity=0.15139
 | period=3.62 [[Julian year (astronomy)|yr]] (1322.4 [[Julian year (astronomy)|d]])
 | inclination=7.2779°
 | asc_node=141.912°
 | arg_peri=168.008°
 | mean_anomaly=88.9729[[Degree (angle)|°]]
 | dimensions={{val|46.70|2.3|ul=km}}<ref name="jpldata"/><br />52.88 ± 3.48&nbsp;km<ref name="Carry2012"/>
 | mass={{nowrap|(5.33 ± 5.77) × 10<sup>17</sup> kg<ref name="Carry2012"/>}}
 | density=
 | rotation={{Convert|8.736|h|d|abbr=on|lk=on}}<ref name="jpldata"/><br />8.73875 h<ref name="Durech2007"/>
 | spectral_type=[[S-type asteroid|S]]
 | abs_magnitude=8.96<ref name="jpldata"/><ref name="Delbo2009"/>
 | albedo={{val|0.2112|0.023}}<ref name="jpldata"/><br />0.211<ref name="Delbo2009"/>
 | mean_motion={{Deg2DMS|0.272226|sup=ms}} / day
 | orbit_ref=<ref name="jpldata">{{Cite web |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=306;cad=1 |title=306 Unitas |work=[[JPL Small-Body Database]] |publisher=[[NASA]]/[[Jet Propulsion Laboratory]] |access-date=11 May 2016}}</ref>
 | observation_arc=124.78 yr (45575 d)
 | uncertainty=0
}}

'''306 Unitas''' is a typical [[Asteroid belt|main belt]] [[asteroid]] that was discovered by [[Elia Millosevich]] on 1 March 1891 in [[Rome]]. The asteroid was named by the director of the Modena Observatory in honor of the Italian astronomer [[Angelo Secchi]] (author of ''Unità delle forze fisiche'')<ref>Schmadel Lutz D.  ''Dictionary of Minor Planet Names'' (fifth edition), Springer, 2003. {{ISBN|3-540-00238-3}}.</ref> and the unification of Italy. It is classified as an [[S-type asteroid]].

In the late 1990s, a network of astronomers worldwide gathered [[light curve]] data that was ultimately used to derive the spin states and shape models of 10 new asteroids, including (306) Unitas. The computed shape model for this asteroid is regular, while the light curve displays two maxima per rotation.<ref name="Durech2007"/><ref>Durech, J.; Kaasalainen, M.; Marciniak, A.; Allen, W. H. et al. "Asteroid brightness and geometry", ''Astronomy and Astrophysics'', Volume 465, Issue 1, April I 2007, pp. 331–337.</ref> Lightcurve data has also been recorded by observers at the Antelope Hill Observatory, which has been designated as an official observatory by the [[Minor Planet Center]].<ref>{{Cite web |url=http://www.antelopehillsobservatory.org/index_files/Page334.htm |title=Lightcurve Results |access-date=9 March 2008 |archive-date=25 July 2011 |archive-url=https://web.archive.org/web/20110725043437/http://www.antelopehillsobservatory.org/index_files/Page334.htm |url-status=dead }}</ref>

Measurements of the [[thermal inertia]] of 306 Unitas give an estimate range from 100 to 260 m<sup>−2</sup> K<sup>−1</sup> s<sup>−1/2</sup>, compared to 50 for [[lunar regolith]] and 400 for coarse sand in an atmosphere.<ref name="Delbo2009"/>

Although 306 Unitas has an orbit similar to the [[Vesta family]] asteroids, it was found to be an unrelated [[Interloper (asteroid)|interloper]] on the basis of its non-matching [[asteroid spectral types|spectral type]]. {{Citation needed|date=March 2008}}

<gallery perrow="1" widths="320px" heights="170px" caption="Orbir diagram of 306 Unitas">
 File:306 Unitas Orbit Diagram.png
</gallery>

==References==
{{Reflist|refs=
<ref name="Carry2012">{{Citation
 | first1    = B.
 | last1     = Carry
 | title     = Density of asteroids
 | journal      = 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="Delbo2009">{{Citation
 | last1     = Delbo'
 | first1    = Marco
 | last2     = Tanga
 | first2    = Paolo
 | title     = Thermal inertia of main belt asteroids smaller than 100&nbsp;km from IRAS data
 | journal      = Planetary and Space Science
 | volume    = 57
 | issue     = 2
 | pages     = 259–265
 |date=February 2009
 | doi       = 10.1016/j.pss.2008.06.015
 | bibcode   = 2009P&SS...57..259D
 | postscript= .
|arxiv = 0808.0869 }}</ref>

<ref name="Durech2007">{{Citation
 | last1     = Durech
 | first1    = J.
 | last2     = Kaasalainen
 | first2    = M.
 | last3     = Marciniak
 | first3    = A.
 | display-authors = 1
 | title     = Physical models of ten asteroids from an observers' collaboration network
 | journal      = Astronomy and Astrophysics
 | volume    = 465
 | issue     = 1
 | pages     = 331–337
 |date=April 2007
 | doi       = 10.1051/0004-6361:20066347
 | bibcode   = 2007A&A...465..331D
 | postscript= .
| doi-access= free
 }}</ref>
}}

== External links ==
* [http://www.antelopehillsobservatory.org/Lightcurves/306.gif Lightcurve plot of (306) Unitas] {{Webarchive|url=https://web.archive.org/web/20120210201537/http://www.antelopehillsobservatory.org/Lightcurves/306.gif |date=10 February 2012 }}, Antelope Hills Observatory
* {{AstDys|306}}
* {{JPL small body}}

{{Minor planets navigator |305 Gordonia |number=306 |307 Nike}}
{{Small Solar System bodies}}
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{{DEFAULTSORT:Unitas}}
[[Category:Background asteroids|000306]]
[[Category:Discoveries by Elia Millosevich]]
[[Category:Named minor planets]]
[[Category:S-type asteroids (Tholen)|000306]]
[[Category:S-type asteroids (SMASS)|000306]]
[[Category:Astronomical objects discovered in 1891|18910301]]


{{S-beltasteroid-stub}}