(523731) 2014 OK394 (provisional designation 1995 SN55) is a trans-Neptunian object that orbits in the outer Solar System beyond the orbit of Neptune. First observed as 1995 SN55 by Spacewatch on 20 September 1995, it was a lost minor planet with an insufficiently defined orbit with only 36 days of observations.[9] On 8 October 2010, it was rediscovered by the Pan-STARRS 1 survey and later announced as 2014 OK394 in July 2016.[1] It was not until November 2020 when amateur astronomers S. Deen and K. Ly identified 2014 OK394 and 1995 SN55 as the same object.[10] This identification was confirmed and announced by the Minor Planet Center in January 2021.[11]
| Discovery[1] | |
|---|---|
| Discovered by | Pan-STARRS 1 |
| Discovery site | Haleakalā Obs. |
| Discovery date | 8 October 2010 |
| Designations | |
| 1995 SN55[2] 2014 OK394 | |
| 3:5 resonant[3] · TNO[4] · distant[2] | |
| Orbital characteristics[4] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 25.14 yr (9,181 days) |
| Earliest precovery date | 20 September 1995 (Spacewatch)[5] |
| Aphelion | 49.153 AU |
| Perihelion | 35.351 AU |
| 42.252 AU | |
| Eccentricity | 0.16333 |
| 274.65 yr | |
| 30.889° | |
| 0° 0m 12.919s / day | |
| Inclination | 4.140° |
| 128.384° | |
| ≈ 4 January 1997[6] | |
| 247.580° | |
| Physical characteristics | |
| 160–280 km (est. 0.08–0.20)[7][8] | |
| 6.2[2][4] | |
Once thought to be a centaur crossing the orbits of the gas giants,[9] 1995 SN55 is now known to be a trans-Neptunian object in a 3:5 orbital resonance with Neptune.[4] With an estimated diameter between 160–280 kilometers (99–170 miles), it was formerly considered one of the largest centaurs.[7][12][13]
1995 SN55 was near perihelion 35.4 AU from the Sun when it was first observed in 1995, by astronomers Nichole Danzl and Arianna Gleason of the Spacewatch survey at Kitt Peak Observatory in Arizona, United States.[5] It was only observed 14 times over 36 days, from 20 September to 26 October 1995.[9] The discovery observations of 1995 SN55 were published and announced by the Minor Planet Center on 11 June 1999.[5] By 2020 the 3-sigma uncertainty in the heliocentric distance to the original orbit solution for 1995 SN55 was approximately ±20 AU (3.0 billion km).[citation needed]
On 30 November 2020, amateur astronomers S. Deen and K. Ly identified 1995 SN55 as the 3:5 resonant trans-Neptunian object (523731) 2014 OK394, which was discovered by Pan-STARRS 1 in 2010.[10] The identification was published by the Minor Planet Center on 27 January 2021.[11]
- Lost minor planet
- 1995 GJ – lost trans-Neptunian object
- 2006 HH123 – misidentified nonexistent minor planet
- (392741) 2012 SQ31 – main-belt asteroid originally misidentified as a trans-Neptunian object
- ^ a b Gibson, B.; Goggia, T.; Primak, N.; Schultz, A.; Willman, M.; Chambers, K.; Chastel, S.; Chen, Y. -T.; Denneau, L.; Flewelling, H.; Holman, M.; Huber, M.; Jedicke, R.; Lackner, M.; Lilly, E.; Lin, H. -W.; Magnier, E.; Micheli, M.; Payne, M.; Veres, P.; Wainscoat, R.; Waters, C.; Weryk, R. (17 July 2016). “MPEC 2016-O154 : 2014 OK394”. Minor Planet Electronic Circular. 2016-O154. Minor Planet Center. Bibcode:2016MPEC….O..154G. Retrieved 23 February 2021.
- ^ a b c d “(523731) = 1995 SN55 = 2014 OK394”. Minor Planet Center. International Astronomical Union. Archived from the original on 30 November 2020. Retrieved 23 February 2021.
- ^ a b Johnston, Wm. Robert (18 August 2020). “List of Known Trans-Neptunian Objects”. Johnston’s Archive. Retrieved 24 February 2021.
- ^ a b c d e “JPL Small-Body Database Browser: 523731 (2014 OK394 = 1995 SN55)” (2020-11-19 last obs.). Jet Propulsion Laboratory. Archived from the original on 30 November 2020. Retrieved 23 February 2021.
- ^ a b c Marsden, Brian G. (11 June 1999). “MPEC 1999-L25 : 1995 SN55, 1998 TF35”. Minor Planet Electronic Circular. 1999-L25. Minor Planet Center. Bibcode:1999MPEC….L…25D. Retrieved 30 November 2020.
- ^ “JPL Horizons On-Line Ephemeris for 523731 (2014 OK394 = 1995 SN55)”. JPL Horizons On-Line Ephemeris System. Jet Propulsion Laboratory. Retrieved 10 February 2021.
Ephemeris Type: OBSERVER, Target Body: 523731 (2014 OK394), Observer Location: Sun (body center) [500@10], Table Settings: QUANTITIES=20. Observer range
(Perihelion occurs when deldot changes from negative to positive.) - ^ a b Brown, Michael E. (23 February 2021). “How many dwarf planets are there in the outer solar system?”. California Institute of Technology. Retrieved 24 February 2021.
- ^ Bruton, Dan. “Conversion of Absolute Magnitude to Diameter for Minor Planets”. Department of Physics, Engineering, and Astronomy. Stephen F. Austin State University. Archived from the original on 23 July 2011. Retrieved 24 February 2021.
- ^ a b c “JPL Small-Body Database Browser: (1995 SN55)” (1995-10-26 last obs.). Jet Propulsion Laboratory. Archived from the original on 30 November 2020. Retrieved 24 February 2021.
(Archive of 36 day observation arc of 1995 SN55) - ^ a b Deen, Sam (30 November 2020). “1995 SN55”. groups.io. Retrieved 23 February 2021.
- ^ a b c “M.P.C. 127300” (PDF). Minor Planet Circular. Minor Planet Center. 27 January 2021. Retrieved 23 February 2021.
- ^ “List Of Centaurs and Scattered-Disk Objects”. Minor Planet Center. International Astronomical Union. Archived from the original on 18 November 2020. Retrieved 24 February 2021. (Archived list of centaurs including 1995 SN55)
- ^ Sokol, Joshua (25 October 2017). “A 300-kilometre space rock has vanished since we saw it in 1995”. New Scientist. Retrieved 24 February 2021.
- ^ “M.P.C. 111781” (PDF). Minor Planet Circular. Minor Planet Center. 25 September 2018. Retrieved 23 February 2021.
- A 300-kilometre space rock has vanished since we saw it in 1995, Joshua Sokol, New Scientist, 25 October 2017
- (523731) 2014 OK394 at the JPL Small-Body Database