View source for 279 Thule

{{Short description|Outer main-belt asteroid}}
{{About|the main-belt asteroid|the Kuiper belt object once nicknamed Ultima Thule|486958 Arrokoth}}
{{Use dmy dates|date=October 2019}}
{{Infobox planet
| minorplanet=yes
| background=#D6D6D6
|image=Орбита астероидов 279.png
|caption=Orbital diagram
| name=279 Thule
| pronounced={{IPAc-en|ˈ|θj|uː|l|iː}}<ref>{{OED|Thule}}</ref>
| adjective=Thulean {{IPAc-en|ˈ|θj|uː|l|i|ə|n}}<ref>{{OED|Thulean}}</ref>
| discoverer=[[Johann Palisa]]
| discovered=25 October 1888
| mpc_name=(279) Thule
| alt_names=A888 UA, 1920 GA<br/>1923 RA, 1927 EC<br/>1954 FF<ref name=jpldata/>
| mp_category=[[Asteroid belt]] ([[Thule asteroid|Thule]])
| orbit_ref=<ref name=jpldata>{{Cite web |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=279;cad=1 |title=279 Thule |work=[[JPL Small-Body Database]] |publisher=[[NASA]]/[[Jet Propulsion Laboratory]] |access-date=11 May 2016}}</ref>
| epoch=31 July 2016 ([[Julian day|JD]] 2457600.5)
| semimajor={{Convert|4.3492770|AU|Gm|abbr=on}}
| perihelion={{Convert|4.2367660|AU|Gm|abbr=on}}
| aphelion={{Convert|4.4617880|AU|Gm|abbr=on|lk=on}}
| eccentricity=0.025869
| period=9.07 [[Julian year (astronomy)|yr]] (3313.0 [[Julian year (astronomy)|d]])
| inclination=2.323774°
| asc_node=72.46791°
| arg_peri=42.36797°
| mean_anomaly=62.75874[[Degree (angle)|°]]
| dimensions={{val|126.59|3.7|ul=km}} {{small|([[IRAS]])}}<ref name=jpldata/>
| mass=
| density=
| rotation={{Convert|23.896|h|d|abbr=on|lk=on}}<ref name=jpldata/>
| spectral_type=B−V=0.75<ref name=jpldata/><br />U−B=0.32<ref name=jpldata/><br />[[D-type asteroid|D]] {{small|([[Tholen classification|Tholen]])}}<ref name=jpldata/><br />[[X-type asteroid|X]] {{small|([[SMASS classification|SMASSII]])}}<ref name=jpldata/>
| abs_magnitude=8.57<ref name=jpldata/>
| albedo={{val|0.0412|0.003}}<ref name=jpldata/>
| single_temperature=133 K
| mean_motion={{Deg2DMS|0.1086622|sup=ms}} / day
| observation_arc=125.34 yr (45780 d)
| uncertainty=0
}}
'''279 Thule''' is a large [[asteroid]] from the outer [[asteroid belt]]. It is classified as a [[D-type asteroid]] and is probably composed of organic-rich [[silicate]]s, [[carbon]] and [[anhydrous]] silicates.  Thule was the first asteroid discovered with a semi-major axis greater than 4 AU.  It was discovered by [[Johann Palisa]] on 25 October 1888 in [[Vienna]] and was named after the ultimate northern land of [[Thule]].
== Thule asteroids ==
{{see also|Groups of minor planets#Other groups out to the orbit of Jupiter{{!}}Minor-planet groups out to Jupiter}}
Thule was the first discovered member of the ''Thule dynamical group'', which as of 2008 is known to consist of three objects: 279 Thule, {{mpl|(186024) 2001 QG|207}}, and {{mpl|(185290) 2006 UB|219}}.<ref name=Broz2008>{{cite journal
|last=Brož |first=M.
|author2=Vokrouhlický, D.
|title=Asteroid families in the first-order resonances with Jupiter
|journal=[[Monthly Notices of the Royal Astronomical Society]]
|volume=390 |issue=2 |pages=715–732 |year=2008
|doi=10.1111/j.1365-2966.2008.13764.x
|doi-access=free
|bibcode=2008MNRAS.390..715B|arxiv=1104.4004|s2cid=53965791
}}</ref>
The orbits of these bodies are unusual. They orbit in the outermost edge of the asteroid belt in a 4:3 [[orbital resonance]] with [[Jupiter]], the result of the periodic force Jupiter exerts on a body with Thule's orbital period, in the same way (though with the reverse effect) as the [[Kirkwood gap]]s in the more inner parts of the asteroid belt.
{|class="wikitable sortable"
|+Known members as of May 2021
!Name
![[semimajor axis]] (au)
![[orbital period|period]] (years)
![[orbital eccentricity|eccentricity]]
![[inclination]] (°)
![[absolute magnitude]]
!Size (km)
|-
|'''279 Thule''' || 4.269 || 8.82 || 0.0432 || 2.334 || 8.53 || {{val|126.59|3.7}}
|-
|{{mpl|185290|2006 UB|219}} || 4.290 || 8.89 || 0.1335 || 7.132 || 13.84 || {{sort|5.85|4.1–10.1}}
|-
|{{mpl|186024|2001 QG|207}} || 4.278 || 8.85 || 0.2513 || 3.238 || 14.53 || {{sort|4.26|3.0–7.4}}
|-
|{{mp|2006 SJ|42}} || 4.286 || 8.87 || 0.0465 || 5.501 || 15.1 || {{sort|3.28|2.3–5.7}}
|-
|{{mp|2008 RE|93}} || 4.288 || 8.88 || 0.1161 || 3.497 || 15.49 || {{sort|2.74|1.9–4.7}}
|-
|{{mp|2014 WN|504}} || 4.297 || 8.91 || 0.2312 || 3.193 || 15.5 || {{sort|2.73|1.9–4.7}}
|-
|{{mp|2014 QX|231}} || 4.283 || 8.86 || 0.3722 || 5.935 || 16.5 || {{sort|1.72|1.2–3.0}}
|}
== See also ==
* [[486958 Arrokoth]] – A [[cubewano]] that was formerly nicknamed Ultima Thule
== References ==
{{reflist}}
== External links ==
* {{AstDys|279}}
* {{JPL small body}}
{{Minor planets navigator |278 Paulina |number=279 |280 Philia}}
{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:000279}}
[[Category:Thule asteroids]]
[[Category:Background asteroids]]
[[Category:Discoveries by Johann Palisa|Thule]]
[[Category:Named minor planets|Thule]]
[[Category:D-type asteroids (Tholen)]]
[[Category:X-type asteroids (SMASS)]]
[[Category:Astronomical objects discovered in 1888|18881025]]
{{beltasteroid-stub}}