2013 FS28

2013 FS28 is an extreme trans-Neptunian object from the extended scattered disc on a highly eccentric orbit in the outermost region of the Solar System. It measures approximately 466 kilometers (290 miles) in diameter and is "probably" a dwarf planet. The detached, extended scattered disc object belongs to the group of extreme trans-Neptunian objects. It was first observed on 16 March 2013, by American astronomers Scott Sheppard and Chad Trujillo at the Cerro Tololo Observatory in Chile.[1][2][3] As of 2021 it is roughly 83±2 AU from the Sun.

2013 FS28
2013 FS28-orbit.png
Orbit of 2013 FS28
Discovery [2][3]
Discovered by(first observed only)
S. S. Sheppard[1]
C. Trujillo[1]
Discovery siteCerro Tololo Obs.
Discovery date16 March 2013
2013 FS28
TNO[4] · ESDO[5]
p-DP[6] · ETNO
Orbital characteristics[4]
Epoch 2020-May-31 (JD 2459000.5)
Uncertainty parameter 7
Observation arc1.13 yr (412 d)
Aphelion358±180 AU (Q)
Perihelion34±AU (q)
196±99 AU (a)
Eccentricity0.83±0.1 (e)
2750±2100 years
348°±10° (M)
0° 0m 1.44s / day
Inclination13.05°±0.02° (i)
204.6°±0.02° (Ω)
≈ 13 September 2111[7]
±26 years[a]
102°±2.5° (ω)
Neptune MOID~8 AU[2]
Physical characteristics
Mean diameter
464 km (est.)[5]
468 km (est.)[6]
0.07 (assumed)[6]
0.09 (assumed)[5]

Orbit and classificationEdit

2013 FS28 being roughly 83 AU (12.4 billion km) from the Sun with only a 1 year observation arc has a poorly constrained orbit. It orbits the Sun at a distance of roughly 34–400 AU once every 3000 years. The large uncertainty in the orbital period is mostly because if the aphelion is further than the nominal solution of ~400 AU than the orbital period will be longer. Its orbit has an exceptionally high eccentricity of 0.8 and an inclination of 13° with respect to the ecliptic.[4] It has a minimum orbital intersection distance with Neptune of 8 AU.[2] The body's observation arc begins with its first official observation in March 2013, using the 4-meter Blanco Telescope at Cerro Tololo Observatory (807).[1][2]

It belongs to a small group of detached objects with perihelion distances of 30 AU or more, and semi-major axes of 150 AU or more.[8] Such extreme trans-Neptunian objects (ETNOs) can not reach such orbits without some perturbing object, which lead to the speculation of Planet Nine.

Given that the object only has observation arc of 1 year with 13 observations, the year of perihelion (closest approach to the Sun) is only known to be 2111±26 years.[a]

Numbering and namingEdit

As of 2018, this minor planet has neither been numbered nor named by the Minor Planet Center. The official discoverer(s) will be defined when the object is numbered.[2]

Physical characteristicsEdit

According to the Johnston's archive and to American astronomer Michael Brown, 2013 FS28 measures 464 and 468 kilometers in diameter based on an assumed albedo of 0.09 and 0.07, respectively.[5][6] On his website, Michael Brown lists this object as "probably" a dwarf planet (400–500 km) based on his 5-class taxonomic system that ranges from "nearly certainly" to "possibly".[6] As of 2018, no rotational lightcurve of has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.[4][9]

See alsoEdit


  1. ^ a b Uncertainty in the perihelion date is 3150 days (1-sigma) or 9450 days (3-sigma).


  1. ^ a b c d Sheppard, S. S.; Trujillo, C. (August 2016). "2013 FS28". Minor Planet Electronic Circular. 2016-Q38 (2016–Q38). Bibcode:2016MPEC....Q...38S. Retrieved 25 October 2018.
  2. ^ a b c d e f g h "2013 FS28". Minor Planet Center. Retrieved 25 October 2018.
  3. ^ a b "List Of Centaurs and Scattered-Disk Objects". Minor Planet Center. Retrieved 25 October 2018.
  4. ^ a b c d e "JPL Small-Body Database Browser: (2013 FS28)" (2014-05-02 last obs.). Jet Propulsion Laboratory. Retrieved 25 October 2018.
  5. ^ a b c d "List of Known Trans-Neptunian Objects". Johnston's Archive. 7 October 2018. Retrieved 25 October 2018.
  6. ^ a b c d e Brown, Michael E. "How many dwarf planets are there in the outer solar system?". California Institute of Technology. Retrieved 25 October 2018.
  7. ^ JPL Horizons Observer Location: @sun (perihelion occurs when deldot changes from negative to positive)
  8. ^ "Database Query: objects q>30, a>150". Minor Planet Center. Retrieved 25 October 2018.
  9. ^ "LCDB Data for (2013+FS28)". Asteroid Lightcurve Database (LCDB). Retrieved 25 October 2018.

External linksEdit