(120178) 2003 OP ₃₂

Asteroid (120178) 2003 OP 32
Properties of the orbit ( animation ) Epoch:  April 27, 2019 ( JD 2,458,600.5)
Orbit type	Cubewano or DO
family	Haumea family
Major semi-axis	43,372  AU
eccentricity	0.109
Perihelion - aphelion	38.63 AU - 48.114 AU
Inclination of the orbit plane	27.2 °
Length of the ascending node	183 °
Argument of the periapsis	70.5 °
Time of passage of the perihelion	December 6, 1961
Sidereal period	285 a 7.7 M
Physical Properties
Medium diameter	${\displaystyle 274_{-25}^{+47}\,\mathrm {km} }$
Albedo	${\displaystyle 0{,}54_{-0,15}^{+0,11}\mathrm {} }$
Rotation period	9.71 4.845
Absolute brightness	4.10 ± 0.07 mag
Spectral class	BV = 0.70 V-R = 0.39
history
Explorer	Michael E. Brown , Chadwick A. Trujillo , David L. Rabinowitz
Date of discovery	July 26, 2003
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.

(120178) 2003 OP ₃₂ is a trans-Neptunian object in the Kuiper belt , which is classified as Cubewano or extended SDO (DO) and as a member of the Haumea family.

discovery

(120178) 2003 OP ₃₂ was on 26 July 2003 by a team of astronomers consisting of Mike Brown , Chad Trujillo and David L. Rabinowitz at Palomar Observatory ( California discovered). He received the minor planet number 120178 from the IAU .

After its discovery, OP _{32 could be identified} in photos taken on July 21, 1990 in 2003 and thus its orbit calculated more precisely. Since then, the planetoid has been observed through various earth-based telescopes. In October 2017, a total of 226 observations over a period of 28 years were available.

properties

Orbit from 2003 OP ₃₂ and other members of the Haumea family.

Orbit

2003 OP ₃₂ orbits the sun in 285.64 years in an elliptical orbit between 38.63  AU and 48.11 AU from its center. The orbit eccentricity is 0.109, the orbit is 27.17 ° inclined to the ecliptic . He last went through perihelion in 1961. The MPC classified 2003 OP ₃₂ as Cubewano , while Marc Buie ( DES ) classified it as an extended SDO (DO). The asteroid is a member of the Haumea family, which consists of fragments from a previous collision on the dwarf planet Haumea .

size

Originally, a calculated diameter of 735 km was assumed; this value was based on an assumed reflectivity of 9% and an absolute brightness of 3.8  ^m . It was assumed that 2003 OP ₃₂ is in hydrostatic equilibrium and that the asteroid should therefore belong to the dwarf planet candidates , based on Mike Brown's taxonomic 5-class system . The latter himself estimates the asteroid's diameter to be only 218 km due to a much higher assumed albedo of 70% and an absolute brightness of 4.4  ^m . Brown (as well as Gonzalo Tancredi in 2010) classify OP ₃₂ as a possible dwarf planet in 2003 . A thermal determination in 2018 resulted in a diameter determination of 274 ⁺⁴⁷₋₂₅ km, an albedo of 54% and an absolute brightness of 4.10 ± 0.07  ^m . The mean temperature is estimated at 42 K (−231 ° C).

In 2008, observations of the light curve indicated a rotation period of 4.845 ± 0.003 hours. In contrast, studies in 2009 showed a rotation period of 9.71 hours that was twice as high.

Provisions of the diameter for 2003 OP ₃₂

year	Dimensions km	source
2010	636.0	Tancredi
2018	735.0	Johnston
2018	274.0 +47.0−25.0	Vilenius et al. a.
2018	218.0	Brown
The most precise determination is marked in bold .

Until 2019, nothing could be learned about the shape and structure of 2003 OP ₃₂ , so that the proportions, mass and density of the asteroid are so far unknown.

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

• Precovery photos from 2003 OP ₃₂
• 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

1. ↑ D. Rabinowitz et al. a .: The Youthful Appearance of the 2003 EL61 Collisional Family (April 2008)
2. ↑ C. Snodgrass et al. a .: Characterization of candidate members of (136108) Haumea's family (December 2009)
3. ↑ MPC : MPEC 2009-R09: Distant Minor Planets (September 2009)
4. ↑ M. Buie et al. a .: Orbit Fit and Astrometric record for 120178 (January 2019)
5. ^ ^{A b} G. Tancredi: Physical and dynamical characteristics of icy “dwarf planets” (plutoids) . IAU. April 1, 2010. Retrieved January 29, 2019.
6. ↑ Johnston's Archives: List of Known Trans-Neptunian Objects (October 2018)
7. ↑ E. Vilenius et al. a .: "TNOs are Cool": A survey of the trans-Neptunian region. XIV. Size / albedo characterization of the Haumea family observed with Herschel and Spitzer (October 2018)
8. ↑ M. Brown : How many dwarf planets are there in the outer solar system? (November 2018)