2012 XR 157
|
Asteroid 2012 XR 157 |
|
|---|---|
| Properties of the orbit ( animation ) | |
| Orbit type |
RKBO 1: 2 ( Twotino ), "Distant Object" |
| Major semi-axis | 47.506 AU |
| eccentricity | 0.223 |
| Perihelion - aphelion | 36,916 AU - 58,097 AU |
| Inclination of the orbit plane | 30 ° |
| Length of the ascending node | 223.7 ° |
| Argument of the periapsis | 276.9 ° |
| Time of passage of the perihelion | November 25, 2054 |
| Sidereal period | 327 a 5.3 M |
| Mean orbital velocity | 4.286 km / s |
| Physical Properties | |
| Medium diameter | approx. 315 km |
| Albedo | 0.08-0.09 |
| Absolute brightness | 5.9 - 6.3 mag |
| history | |
| Explorer |
Chadwick A. Trujillo Scott S. Sheppard |
| Date of discovery | December 11, 2012 |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items. | |
2012 XR 157 is a large trans-Neptunian object in the Kuiper belt , which is classified as a resonant KBO ( Twotino ) in terms of railway dynamics . Due to its size, the asteroid is one of the dwarf planet candidates .
discovery
2012 XR 157 was discovered on December 11, 2012 by Chad Trujillo and Scott Sheppard with the 4.0 m Víctor M. Blanco telescope ( DE Cam) at the Cerro Tololo Observatory ( Chile ). The discovery was announced on April 7, 2014 after confirmation by the Las Campanas Observatory .
After its discovery in 2012, XR 157 could be identified on photos taken as part of the Sloan Digital Sky Survey program (SDSS) at the Apache Point Observatory ( New Mexico ) going back to January 31, 2006, thus changing its observation period extend six years to calculate its orbit more accurately. Since then, the planetoid has been observed through various earth-based telescopes. In September 2018 there were a total of 90 observations over a period of 12 years. The last observation so far was carried out in December 2017 at the Pan-STARRS telescope (PS1) ( Maui ). (As of March 27, 2019)
properties
Orbit
2012 XR 157 orbits the sun in 327.44 years in an elliptical orbit between 36.91 AU and 58.10 AU from its center. The orbit eccentricity is 0.223, the orbit is inclined 30.03 ° to the ecliptic . The planetoid is currently 40.53 AU from the sun. He will next pass perihelion in 2054, so the last perihelion should have occurred in 1727.
Marc Buie ( DES ) classifies the planetoid as Twotino ( 1: 2 resonance with Neptune ), while the Minor Planet Center does not have a specific classification; the latter classifies it as a non-SDO and generally as a “distant object” .
size
A diameter of 315 km is currently assumed, based on a reflectivity of 8% and an absolute brightness of 5.9 m . Based on this diameter, the total area is about 312,000 km². The apparent magnitude of the 2012 XR 157 is 22.59 m .
Since it is conceivable that 2012 XR 157 is in hydrostatic equilibrium due to its size and could thus be largely round, it may meet the criteria for classification as a dwarf planet . Mike Brown expects that it is at 2012 XR 157 to perhaps is a dwarf planet.
| year | Dimensions km | source |
|---|---|---|
| 2018 | 243.0 | Johnston |
| 2018 | 315.0 | Brown |
| The most precise determination is marked in bold . | ||
See also
- List of trans-Neptunian objects
- List of dwarf planets of the solar system
- List of asteroids
- List of moons from asteroids
Web links
- How many dwarf planets are there in the outer solar system? Current list of the largest TNOs from Mike Brown
- Free the dwarf planets! Mike Brown's column on the IAU and the dwarf planets regarding their classifications (23 August 2011)
Individual evidence
- ^ A b Marc W. Buie : Orbit Fit and Astrometric record for 12XR157 . SwRI (Space Science Department). Retrieved March 27, 2019.
- ↑ a b c 2012 XR157 at the IAU Minor Planet Center (English). Accessed March 27, 2019.
- ↑ v ≈ π * a / period (1 + sqrt (1-e²))
- ↑ MPC : MPEC 2014-G35: 2012 XR157 . IAU . April 7, 2014. Accessed March 27, 2019.
- ↑ 2012 XR157 in the Small-Body Database of the Jet Propulsion Laboratory (English). Retrieved March 27, 2019.
- ^ A b Wm. R. Johnston: List of Known Trans-Neptunian Objects . Johnston's Archives. October 7, 2018. Retrieved March 27, 2019.
- ↑ MPC : MPEC List Of Centaurs and Scattered-Disk Objects . IAU . Retrieved March 27, 2019.
- ↑ 2012 XR157 in the database of the "Asteroids - Dynamic Site" (AstDyS-2, English).
- ↑ a b Mike Brown : How many dwarf planets are there in the outer solar system? . CalTech . November 12, 2018. Retrieved March 27, 2019.