(528381) 2008 ST291
{{Short description|Trans-Neptunian object}}
{{Use dmy dates|date=May 2019}}
{{DISPLAYTITLE:{{mp|(528381) 2008 ST|291}}}}
{{Infobox planet
| minorplanet = yes
| name = {{mp|(528381) 2008 ST|291}}
| background = #C2E0FF
| image = 2008 ST291-orbit.png
| image_size =
| caption = Orbit of {{mp|(528381) 2008 ST|291}}
| discoverer = M. E. Schwamb
M. E. Brown
D. L. Rabinowitz
| discovery_site = Palomar Obs.
| discovered = 24 September 2008
| mpc_name = {{mp|(528381) 2008 ST|291}}
| alt_names = {{mp|2008 ST|291}}
| pronounced =
| named_after =
| mp_category = TNO{{·}}SDO
res 1:6
| epoch = 27 April 2019 (JD 2458600.5)
| uncertainty = 3
| observation_arc = 9.27 yr (3,385 d)
| aphelion = {{Convert|157.437|AU|Tm|abbr=on}}
| perihelion = {{Convert|42.3114440|AU|Tm|abbr=on}}
| semimajor = {{Convert|99.8742972|AU|Tm|abbr=on}}
| eccentricity = 0.5763530
| period = 998.30 yr (364,629 d)
| mean_anomaly = 23.349°
| mean_motion = {{Deg2DMS|0.0010|sup=ms}} / day
| inclination = 20.758°
| asc_node = 330.97°
| arg_peri = 324.65°
| satellites =
| mean_diameter = {{val|549|ul=km}} {{small|(est.)}}
{{val|584|u=km}} {{small|(est.)}}
{{val|612|u=km}}{{efn|Based on AstDyS magnitude and same 0.09 albedo as Brown and Johnston, using Bruton formula}}
{{val|345|-|773|u=km}}{{efn|Based on averaged magnitude of 4.433 and typically assumed minor planet albedo range of 0.05 ~ 0.25, using Bruton formula}}
| rotation =
| spectral_type =
}}
{{mp|(528381) 2008 ST|291}}, provisional designation {{mp|2008 ST|291}}, is a 1:6 resonant trans-Neptunian object located in the outermost region of the Solar System that takes almost a thousand years to complete an orbit around the Sun. It was discovered on 24 September 2008 by American astronomers Megan Schwamb, Michael Brown and David Rabinowitz at the Palomar Observatory in California, with no known earlier precovery images.
Numbering and naming
This minor planet was numbered by the Minor Planet Center on 18 May 2019 ({{small|M.P.C. 114657}}). As of 2019, it has not been named.
Orbit and classification
File:2008ST291-orbit.png and Neptune]]
{{see also|List of Solar System objects most distant from the Sun}}
{{mp|2008 ST|291}} is located at the 1:6 Neptune resonance of 99 AU meaning that it completes roughly 1 orbit for every 6 orbits Neptune makes. It orbits the Sun at a distance of 42.3–157.5 AU once every 998 years and 4 months (semi-major axis of 99.89 AU). Its orbit has an eccentricity of 0.58 and an inclination of 21° with respect to the ecliptic. Currently located at 60.9 AU from the Sun, the object came to perihelion in 1954.
Physical characteristics
Based on an absolute magnitude of 4.4, {{mp|2008 ST|291}} is estimated by the Johnston's Archive to be about {{convert|584|km|mi}} in diameter, assuming a typical albedo of 0.09 for trans-Neptunian objects. Astronomer Mike Brown estimates a slightly smaller 549 km from the same albedo and a fainter 4.6 magnitude. The Asteroid Dynamic Site records a brighter 4.3 magnitude, which calculates to 612 km using the same albedo (and same formula as Johnston's); using the average of these magnitudes and a standard assumed minor planet albedo range of 0.25 ~ 0.05, possible sizes of 345 to 773 km are produced.
See also
Notes
{{notelist}}
References
{{Reflist|refs=
|type = 2017-12-31 last obs.
|title = JPL Small-Body Database Browser: (2008 ST291)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3476640
|publisher = Jet Propulsion Laboratory
|accessdate = 29 May 2019}}
|title = (528381) 2008 ST291
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=2008+ST291
|accessdate = 29 May 2019}}
|title = MPC/MPO/MPS Archive
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
|accessdate = 29 May 2019}}
|title = MPEC 2009-V68 : 2008 ST291
|work = Minor Planet Center
|date = 14 November 2009
|url = https://minorplanetcenter.net//mpec/K09/K09V68.html
|accessdate = 29 May 2019}}
|title = 2008 ST291 – Ephemerides
|publisher = AstDyS-2, Asteroids – Dynamic Site
|url = https://newton.spacedys.com/astdys/index.php?pc=1.1.3.0&n=2008ST291
|accessdate = 19 August 2019}}
|title = List of Known Trans-Neptunian Objects
|work = Johnston's Archive
|date = 25 May 2019
|last = Johnston |first= Wm. Robert
|url = http://www.johnstonsarchive.net/astro/tnoslist.html
|accessdate = 29 May 2019}}
|title = How many dwarf planets are there in the outer solar system?
|publisher = California Institute of Technology
|last = Brown |first= Michael E.
|url = http://web.gps.caltech.edu/~mbrown/dps.html
|accessdate = 29 May 2019}}
|author1=Dan Bruton
|title=Conversion of Absolute Magnitude to Diameter for Minor Planets
|url=http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html
|website=Stephen F. Austin State University, College of Sciences and Mathematics, Department of Physics, Engineering and Astronomy
|accessdate=15 August 2019
|archiveurl=https://web.archive.org/web/20110723191750/http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html
|archivedate=23 July 2011}}
}}
External links
- [https://www.boulder.swri.edu/~buie/kbo/astrom/528381.html Orbit Fit and Astrometric record for 528381], Marc W. Buie, SwRI
- [https://www.minorplanetcenter.net/iau/lists/t_centaurs.html List Of Centaurs and Scattered-Disk Objects], Minor Planet Center
- {{AstDys|2008ST291}}
- {{JPL small body|id=3476640}}
{{Dwarf planets}}
{{Trans-Neptunian objects}}
{{Minor planets navigator | |number=528381 |PageName={{mp|(528381) 2008 ST|291}} | }}{{Extreme trans-Neptunian objects}}{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:2008 ST291}}
Category:Discoveries by Megan E. Schwamb
Category:Discoveries by Michael E. Brown