| 词条 | 2008 ST291 |
| 释义 |
| minorplanet = yes | background = #C2E0FF | name = {{mp|2008 ST|291}} | symbol = | image = | caption = | discovery_ref = [1] | discoverer = M. E. Schwamb M. E. Brown D. L. Rabinowitz | discovered = September 24, 2008 | mpc_name = {{mp|2008 ST|291}} | mp_category = TNO (SDO)[2][3] 6:1?[3] | orbit_ref = | epoch = 23 March 2018 (JD 2458200.5) | uncertainty = 4 | observation_arc= 3286 days (9.00 yr) | aphelion = {{Convert|156.396|AU|Tm|abbr=on|lk=on}} | perihelion = {{Convert|42.271|AU|Tm|abbr=on}} | semimajor = {{Convert|99.333|AU|Tm|abbr=on}} | eccentricity = 0.57445 | period = 990.04 yr (361611 d) | avg_speed = | inclination = 20.7849° | asc_node = 331.0475° | mean_anomaly = 23.2101° | mean_motion = 0.0009955°/day | arg_peri = 324.3727° | satellites = | dimensions = 612 km {{small|(est. at 0.09)}}[6] 370–820 km {{small|(generic)}}[7] | mass = | density = | albedo = | spectral_type = | magnitude = 22.3[1][9] | abs_magnitude = 4.2 }}{{mp|2008 ST|291}}, also written as 2008 ST291, is a trans-Neptunian object with an absolute magnitude of 4.2, making it possibly a dwarf planet.[1] It is located near the 1:6 Neptune resonance of 99.4 AU (compared to its 99.3 ± 0.2 AU), meaning that it completes roughly 1 orbit for every 6 orbits Neptune makes.[3] Size estimate{{mp|2008 ST|291}} is estimated to be about {{convert|612|km|mi}} in diameter, assuming a typical albedo of 0.09 for trans-Neptunian objects.[6] However, because its albedo is unknown and it has an absolute magnitude of 4.2, it could be anywhere between 370 and 820 km in diameter.[7]Distance{{see also|List of most distant trans-Neptunian objects}}{{mp|2008 ST|291}}, currently 60.9 AU from the Sun,[9] came to perihelion in 1954. It takes almost one thousand years to orbit the Sun.{{mp|2008 ST|291}} has only been observed 28 times over four oppositions and has an orbit quality of 4 (0 being best; 9 being worst).See also
References1. ^{{cite web |url=http://web.gps.caltech.edu/~mbrown/dps.html |title=How many dwarf planets are there in the outer solar system? |publisher=Gps.caltech.edu |date=2015-07-21 |accessdate=20 September 2016}} [2][3][4][5][6][7]2. ^1 {{cite web |title=List Of Centaurs and Scattered-Disk Objects |publisher=Minor Planet Center |url=http://www.minorplanetcenter.org/iau/lists/Centaurs.html |accessdate=2009-12-06}} 3. ^1 2 3 {{cite web |author=Marc W. Buie |author-link=Marc W. Buie |type=last observation: 2010-10-09 using 20 of 23 observations over 2.04 years |title=Orbit Fit and Astrometric record for 08ST291 |publisher=SwRI (Space Science Department) |url=http://www.boulder.swri.edu/~buie/kbo/astrom/08ST291.html |accessdate=2009-12-06}} 4. ^1 2 {{cite web |title=MPEC 2009-V68 : 2008 ST291 |publisher=IAU Minor Planet Center |date=2009-11-14 |url=http://minorplanetcenter.org/mpec/K09/K09V68.html |accessdate=2009-12-06}} 5. ^1 2 {{cite web |title=AstDyS 2008 ST291 Ephemerides |publisher=Department of Mathematics, University of Pisa, Italy |url=http://hamilton.dm.unipi.it/astdys/index.php?pc=1.1.3.0&n=2008ST291 |accessdate=31 July 2018}} 6. ^1 2 {{cite web |title=Absolute Magnitude (H) |publisher=NASA/JPL |url=http://neo.jpl.nasa.gov/glossary/h.html |accessdate=2009-12-06| archiveurl= https://web.archive.org/web/20091126011612/http://neo.jpl.nasa.gov/glossary/h.html |archivedate=26 November 2009 |deadurl= no}} 7. ^1 2 {{cite web |title=Conversion of Absolute Magnitude to Diameter for Minor Planets |publisher=Department of Physics & Astronomy (Stephen F. Austin State University) |author=Dan Bruton |url=http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html |accessdate=2008-12-09 |archiveurl=https://web.archive.org/web/20081210190134/http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html |archivedate=10 December 2008 |deadurl=yes |df= }} }} External links
6 : Scattered disc and detached objects|Minor planet object articles (unnumbered)|Discoveries by Michael E. Brown|Discoveries by David L. Rabinowitz|Possible dwarf planets|Astronomical objects discovered in 2008 |
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