# (50000) Quaoar

Asteroid
(50000) Quaoar
Quaoar as recorded by the Hubble Space Telescope , total of 16 exposures (2002).
Properties of the orbit ( animation )
Epoch:  April 27, 2019 ( JD 2,458,600.5)
Orbit type CKBO ( "hot" ),
"Distant Object"
Major semi-axis 43.692  AU
eccentricity 0.04
Perihelion - aphelion 41.964 AU - 45.42 AU
Inclination of the orbit plane 8 °
Length of the ascending node 188.8 °
Argument of the periapsis 146.4 °
Time of passage of the perihelion November 19, 2066
Sidereal period 288 a 9.7 m
Mean orbital velocity 4.469 km / s
Physical Properties
Medium diameter ${\ displaystyle 1111 _ {- 4.6} ^ {+ 4.6} \ mathrm {km}}$
Dimensions 1.3 - 1.5 ± 0.1  ·  10 21 kg
Albedo 0.109 ± 0.007
Medium density 2.01 ± 0.14 g / cm³
Rotation period 8.8400 h (0.368 d ) or
17.6788 ± 0.0004 h (0.737 d )
Absolute brightness 2.82 ± 0.06 mag
Spectral class C
B-V = 0.939 ± 0.008
VR = 0.650 ± 0.010
VI = 1.280 ± 0.020
BR = 1.588 ± 0.021
history
Explorer Chadwick A. Trujillo
Michael E. Brown
Date of discovery June 6, 2002
Another name 2002 LM 60
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.

(50000) Quaoar [ ˈkwɑːwɑr ] (earlier name 2002 LM 60 ) is a large trans-Neptunian object in the Kuiper belt , which is classified as Cubewano in terms of orbital dynamics . Due to its size, the asteroid is one of the candidates for the class of dwarf planets introduced by the International Astronomical Union (IAU) on August 24, 2006 . Quaoar has a moon named Weywot .

## Discovery and naming

Quaoar was discovered on June 6, 2002 by the American astronomers Chad Trujillo ( Gemini ) and Mike Brown ( CalTech ) in Pasadena in images from June 4, 2002, taken with the 1.2 m Oschin Schmidt telescope at the Palomar Observatory made by the California Institute of Technology ; while he was in the constellation serpentine bearer . The discovery was announced on October 7, 2002 at a meeting of the American Astronomical Society , the planetoid was given the provisional designation 2002 LM 60 . After the announcement, Quaoar was considered the tenth planet in some media. Not by chance, but apparently because of the superficial significance of the discovery, the IAU assigned the round minor planet number 50,000 to Quaoar, together with the 20,000 for Varuna (which, according to general opinion, has now proven to be smaller than originally assumed); the dwarf planets Eris and Pluto, for example, were numbered according to the order in which their orbital elements were confirmed.

On 20 November 2002, the received planetoid to the proposal of explorers through the official name Quaoar , after the divine shapeless and sexless creative power of the creation myth of the North American Tongva - Indians who enter in the Los Angeles area to the north-western Mexico Life. The explorers chose the name with the intuitive pronunciation Kwawar ; however, the preferred pronunciation of the Tongva was Qua-o-ar .

Like all other Trans-Neptunian objects except Pluto , Quaoar has no official or commonly used astronomical symbol . Quaoar symbols circulating on the internet such as B. are designs from private individuals. An official symbol assignment is not to be expected, since astronomical symbols no longer play a role in modern astronomy.

Quaoar was photographed by the astronomer Charles Kowal as early as 1982 , but was not identified as an asteroid. Based on this, Quaoar could be identified in a number of earlier observations and thus its orbit calculated more precisely. The earliest known image dates from May 25, 1954 and was taken as part of the Palomar Observatory Sky Survey program (POSS) at the Palomar Observatory.

## properties

 The orbit of Quaoar (blue) compared to those of Pluto (red) and Neptune (gray)

### Orbit

Quaoar orbits the sun in 288.81 years in an almost perfect orbit between 41.96  AU and 45.42 AU from its center. The orbit eccentricity is 0.040, the orbit is 7.99 ° inclined to the ecliptic . In February 2019, the planetoid was 42.9 AU from the sun. The next time it will pass perihelion in 2066, the last perihelion should therefore have taken place in 1778.

At the end of March 2003, Quaoar was about 13.6 AU from Pluto, making it the nearest large TNO to the Pluto - Charon system.

Both Marc Buie ( DES ) and the Minor Planet Center classify Quaoar as the largest Cubewano (the latter also generally referred to as “Distant Object” ); its orbit is not significantly disturbed by Neptune , but it is one of the "hot" Cubewanos.

Hubble image for sizing Quaoar.

### Size and mass

Quaoar's diameter was initially determined to be 1250 ± 50 km, using the Hubble Space Telescope , among other things . This made it the largest object discovered in the solar system since Pluto until the discovery of (90482) Orcus and (90377) Sedna . Quaoar was the first TNO in which the images from the Hubble telescope were used with new methods for direct measurement; because of its distance, the asteroid is at the limit of the telescope's resolution of 40 arc seconds , which is why the images on the pixels adjacent to Quaoar were smeared. Through comparisons with background stars and the point spread function for the telescope, Brown and Trujillo were later able to put the assessment into perspective. In a similar way, the size of Eris was determined in 2011 .

Using the data from the Spitzer Space Telescope , Stansberry et al. a. 2008 and Brucker u. a. In 2009 the diameter of Quaoar was determined to be around 900 km on the basis of a higher albedo of 19%. The resulting density of 4.2 grams per cubic centimeter would be unusually high for objects in the Kuiper Belt.

More recent studies in 2013 with the Herschel space telescope (instruments SPIRE and PACS) combined with the revised data from the Spitzer telescope (instrument MIPS) came to the conclusion that the diameter is more like 1073.6 ± 37.9 km. The density would then be 2.15 ± 0.40 g / cm³. Another group of researchers calculated a value of 1111 ± 4.6 km on the occasion of a star occultation on May 4, 2011. This results in a density of 2.01 ± 0.40 g / cm³, which is not unusual for Kuiper belt objects. The apparent magnitude of Quaoar is 18.97  m .

Using light curve observations in 2003, Quaoar rotates once around its axis in 17 hours and 40.7 minutes. From this it follows that in a Quaoar year he performs 143203.4 self- rotations (“days”). However, this is still fraught with uncertainties, as the observation time at that time was insufficient and the error rate is around 30%. In contrast, light curve observations in 2006 suggested a rotation period of 8 hours and 50.4 minutes that was half as long, which would double the number of Quaoar days with 286387.4 revolutions.

### Dwarf planet candidate

The discovery of Quaoar weakened Pluto's status as a planet, especially since astronomers suspect other objects of Quaoar's size in the Kuiper Belt. Later, in Eris , an object was even found there that appeared to be larger than Pluto. Due to its size, Quaoar is most likely in hydrostatic equilibrium , so that an assignment to the dwarf planets can be expected. According to Mike Brown, it is almost certainly a dwarf planet. Gonzalo Tancredi also suggests that the IAU officially recognize him as such.

Provisions of the diameter for quaoar
year Dimensions km source
2004 1260.0 ± 190.0 Brown et al. a.
2007 844.4 +206.7−189.6 (System) Stansberry et al. a.
2008 1290.0 Tancredi
2008 908.0 +112.0−118.0(System)
830.0 +178.0−142.0 (System)
Brucker et al. a.
2010 908.0 Tancredi
2010 893.1 (system)
890.0 ± 70.0
Frasier et al. a.
2011 1170.0 Braga-Ribas et al. a.
2013 1073.6 ± 37.9 (system)
1070.0 ± 38.0
Fornasier et al. a.
2013 1128 +48.0−34.0 Braga-Ribas et al. a.
2013 <1160.0 ± 240.0 Frasier et al. a.
2013 910.0 (system) Mommert et al. a.
2014 > 1138.0 ± 25.0 Davis et al. a.
2014 <917.0 (system)
<914.0
Thirouin et al. a.
2014 1111.0 ± 4.6 Braga-Ribas et al. a.
2015 908.0 LightCurve DataBase
2017 1083.0 ± 50.0 (system)
1079.0 ± 50.0
Brown et al. a.
2017 1071.0 +53.0−57.0 (System) E. Lellouch et al. a.
2018 1092.0 Brown
The most precise determination is marked in bold .

### surface

In December 2004, the Japanese eight-meter Subaru telescope succeeded in detecting crystalline water ice and ammonia hydrate on the surface of Quaoar. This is surprising, since at a surface temperature of 50 Kelvin there should actually only be amorphous ice without a crystal structure . However, the existence of crystalline ice requires temperatures up to 110 Kelvin. It is believed that there is still enough radioactivity heat inside Quaoar to generate these temperatures. The result is doing a Kryovulkanismus , as well as on Neptune moon Triton .

Investigations with the VLT of the European Southern Observatory and the Spitzer Space Telescope showed a comparatively homogeneous surface with methane , ethane , ammonium hydroxide and nitrogen ice in 2015. The spectrum also suggests traces of carbon monoxide and carbon dioxide . Quaoar's surface appears to be relatively young.

Four recordings by New Horizons

### Exploration by spacecraft

In 2011 it was calculated that a flyby mission to Quaoar would take 13.57 years; a swing-by to Jupiter would be planned based on the start dates on December 25, 2016 (elapsed), November 22, 2027, December 22, 2028, January 22, 2030 or December 20, 2040. Quaoar would then be 41 when the probe arrives up to 43 AU away from the sun.

On July 13 and 14, 2016, the high-resolution camera LORRI of the New Horizons space probe took four pictures exactly one year after the Pluto flyby. The image from a distance of 2.1 billion km (14 AU) only shows the object as a blurred point, but it is still of scientific value because the object was recorded from a different angle than from Earth. The image provides information about the surface's ability to scatter light in other directions.

In May 2018, Pontus Brandt u. a. of the Johns Hopkins University Applied Physics Laboratory presented a study of an interstellar spacecraft that could fly past Quaoar to enter the interstellar medium in the 2030s .

## moon

In February 2007, a team led by Mike Brown announced the discovery of a moon 81 km in diameter, which was discovered on recordings from 2006. In November 2009 the moon was given the name Weywot (Quaoar I) . Weywot (heaven) was the first creation of the Quaoar Indian power of creation. By analyzing the orbit, the mass of the system could be determined to be 1.4  ·  10 21 kg.

The Quaoar system at a glance:

Components Physical parameters Path parameters discovery
Surname Throughput
diameter
(km)
Relative
size
%
Mass
(kg)
Major
semi-axis
(km)
Orbital time
(d)
eccentricity
Inclination
to Quaoar's
equator
Date of discovery
Date of publication
(50000) Quaoar
1111.0 100.00 1.40 · 10 21 - - - - June 6, 2002 October 7, 2002
0
Weywot
(Quaoar I)
81.0 7.29 8.50 10 17 13800 12,438 0.148 14.0 ° February 14, 2006
February 22, 2007

Commons : 50000 Quaoar  - Album with pictures, videos and audio files

## Individual evidence

1. a b M. Buie : Orbit Fit and Astrometric record for 50,000 . SwRI (Space Science Department). Retrieved March 4, 2019.
2. a b MPC : MPEC 2010-S44: Distant Minor Planets (2010 OCT.11.0 TT) . IAU . September 25, 2010. Accessed March 4, 2019.
3. a b E. Lellouch u. a .: “TNOs are Cool”: A survey of the trans-Neptunian region. IX. Thermal properties of Kuiper belt objects and Centaurs from combined Herschel and Spitzer observations (PDF) . In: Astronomy and Astrophysics . 557, No. A60, June 10, 2013, p. 19. bibcode : 2013A & A ... 557A..60L . doi : 10.1051 / 0004-6361 / 201322047 .
4. a b c (50000) Quaoar at the IAU Minor Planet Center (English) Retrieved March 4, 2019.
5. v ≈ π * a / period (1 + sqrt (1-e²))
6. a b c Braga-Ribas u. a .: Stellar Occultations by Transneptunian and Centaurs Objects: results from more than 10 observed events (PDF) . In: XIV Latin American Regional IAU Meeting . 44, October 2014, pp. 3-3. bibcode : 2014RMxAC..44 .... 3B .
7. W. Fraser et al. a .: The Mass, Orbit, and Tidal Evolution of the Quaoar-Weywot System (PDF) . In: Icarus . 222, No. 1, November 5, 2012, pp. 357-363. arxiv : 1211.1016 . bibcode : 2013Icar..222..357F . doi : 10.1016 / j.icarus.2012.11.004 .
8. S. Fornasier u. a .: “TNOs are Cool”: A survey of the trans-Neptunian region. VIII. Combined Herschel PACS and SPIRE observations of nine bright targets at 70-500 µm (PDF) . In: Astronomy and Astrophysics . 555, No. A15, June 19, 2013, p. 22. arxiv : 1305.0449v2 . bibcode : 2013A & A ... 555A..15F . doi : 10.1051 / 0004-6361 / 201321329 .
9. a b D. Rabinowitz u. a .: Direct The Diverse Solar Phase Curves of Distant Icy Bodies. I. Photometric Observations of 18 Trans-Neptunian Objects, 7 Centaurs, and Nereid (PDF) . In: The Astronomical Journal . 133, No. 1, May 31, 2006, pp. 26-43. arxiv : astro-ph / 0605745 . bibcode : 2007AJ .... 133 ... 26R . doi : 10.1086 / 508931 .
10. a b J. Ortiz et al. a .: Rotational brightness variations in Trans-Neptunian Object 50000 Quaoar . In: Astronomy and Astrophysics . 409, October 2003, pp. L13-L16. bibcode : 2003A & A ... 409L..13O . doi : 10.1051 / 0004-6361: 20031253 .
11. a b Braga-Ribas u. a .: The Size, Shape, Albedo, Density, and Atmospheric Limit of Transneptunian Object (50000) Quaoar from Multi-chord Stellar Occultations . In: The Astrophysical Journal . 773, July 22, 2013, p. 26. bibcode : 2013ApJ ... 773 ... 26B . doi : 10.1088 / 0004-637X / 773/1/26 .
12. a b LCDB Data for (50000) Quaoar . MinorPlanetInfo. April 2015. Retrieved March 4, 2019.
13. a b W. Grundy: Quaoar and Weywot (50000 2002 LM60) . Lowell Observatory . December 29, 2018. Retrieved March 4, 2019.
14. I. Belskaya et al. a .: Updated taxonomy of trans-neptunian objects and centaurs: Influence of albedo . In: Icarus . 250, April 2015, pp. 482-491. bibcode : 2015Icar..250..482B . doi : 10.1016 / j.icarus.2014.12.004 .
15. N. Peixinho et al. a .: The bimodal colors of Centaurs and small Kuiper belt objects (PDF) . In: Astronomy and Astrophysics . 546, No. A86, June 14, 2012, p. 12. arxiv : 1206.3153 . bibcode : 2012A & A ... 546A..86P . doi : 10.1051 / 0004-6361 / 201219057 .
16. MPC : MPEC 2002-T34: 2002 LM60 . IAU . October 7, 2002. Retrieved March 4, 2019.
17. ^ Karl Urban (raumfahrer.net): Tenth planet attacks Pluto . October 8, 2002. Retrieved March 4, 2019.
18. (50000) Quaoar in the Small-Body Database of the Jet Propulsion Laboratory (English). Retrieved March 4, 2019.
19. a b M. Brown , B. Butler: The density of mid-sized Kuiper belt objects from ALMA thermal observations . In: The Astronomical Journal . 154, No. 1, February 23, 2017, p. 19, 7. arxiv : 1702.07414 . bibcode : 2017AJ .... 154 ... 19B . doi : 10.3847 / 1538-3881 / aa6346 .
20. ^ A b W. Fraser, M. Brown : Quaoar: A Rock in the Kuiper belt . In: The Astrophysical Journal . 714, No. 2, March 30, 2010, pp. 1547-1550. arxiv : 1003.5911 . bibcode : 2013A & A ... 555A..15F . doi : 10.1088 / 0004-637X / 714/2/1547 .
21. Emily Lakdawalla: Quaoar: A rock in the Kuiper Belt The Planetary Society Blog, April 1, 2010 (English)
22. Distant Kuiper belt object Quaoar is rock sphere SpectrumDirekt, April 7, 2010
23. AstDyS: 2004TY364 . Universita di Pisa. Retrieved March 4, 2019.
24. a b Mike Brown : How many dwarf planets are there in the outer solar system? . CalTech . November 12, 2018. Retrieved March 4, 2019.
25. a b Gonzalo Tancredi: Physical and dynamical characteristics of icy “dwarf planets” (plutoids) (PDF) . In: International Astronomical Union (Ed.): Icy Bodies of the Solar System: Proceedings IAU Symposium No. 263, 2009 . 2010. doi : 10.1017 / S1743921310001717 . Retrieved March 4, 2019.
26. M. Brown , C. Trujillo et al. a .: Direct Measurement of the Size of the Large Kuiper Belt Object (50000) Quaoar (PDF) . In: The Astronomical Journal . 127, No. 4, April 2004, pp. 2413-2417. bibcode : 2004AJ .... 127.2413B . doi : 10.1086 / 382513 .
27. J. Stansberry et al. a .: Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope (PDF) . In: University of Arizona Press . 592, No. 161-179, February 20, 2007. bibcode : 2008ssbn.book..161S .
28. ^ Gonzalo Tancredi, Sofía Favre: DPPH List . In: Dwarf Planets and Plutoid Headquarters, from Which are the dwarfs in the solar system? . August. Retrieved March 4, 2019.
29. M. Brucker et al. a .: High Albedos of Low Inclination Classical Kuiper Belt Objects (PDF) . In: Icarus . 201, No. 1, December 18, 2008. arxiv : 0812.4290 . bibcode : 2009Icar..201..284B . doi : 10.1016 / j.icarus.2008.12.040 .
30. Braga-Ribas et al. a .: Stellar Occultations by TNOs: the January 08, 2011 by (208996) 2003 AZ84 and the May 04, 2011 by (50000) Quaoar (PDF) . In: The Astrophysical Journal . 773, October 2011, p. 26. bibcode : 2011epsc.conf.1060B .
31. W. Frasier et al. a .: Limits on Quaoar's Atmosphere (PDF) . In: The Astrophysical Journal . 774, No. 2, August 9, 2013, p. L18, 4. arxiv : 1308.2230 . bibcode : 2013ApJ ... 774L..18F . doi : 10.1088 / 2041-8205 / 774/2 / L18 .
32. M. Mommert et al. a .: Remnant planetesimals and their collisional fragments: Physical characterization from thermal-infrared observations . September 23, 2013. Accessed March 4, 2019.
33. A. Davis et al. a .: Observation and analysis of a single-chord stellar occultation by Kuiper belt object (50000) Quaoar . In: American Astronomical Society, AAS Meeting . 223, January 2014, p. 247.08. bibcode : 2014AAS ... 22324708D .
34. A. Thirouin et al. a .: Rotational properties of the binary and non-binary populations in the trans-Neptunian belt . In: Astronomy & Astrophysics . 569, July 4, 2014, p. A3, 20. arxiv : 1407.1214 . bibcode : 2014A & A ... 569A ... 3T . doi : 10.1051 / 0004-6361 / 201423567 .
35. E. Lellouch et al. a .: The thermal emission of Centaurs and Trans-Neptunian objects at millimeter wavelengths from ALMA observations . In: Astronomy & Astrophysics . 608, September 20, 2017, p. A45, 21. arxiv : 1709.06747 . bibcode : 2017A & A ... 608A..45L . doi : 10.1051 / 0004-6361 / 201731676 .
36. M. Barucci et al. a .: (50000) Quaoar: Surface composition variability . In: Astronomy and Astrophysics . 584, No. A107, December 1, 2015, p. 7. bibcode : 2015Icar..257..130G . doi : 10.1051 / 0004-6361 / 201526119 .
37. R. McGranaghan et al. a .: A Survey of Mission Opportunities to Trans-Neptunian Objects . In: Journal of the British Interplanetary Society . 64, 2011, pp. 296-303. bibcode : 2011JBIS ... 64..296M .
38. Mike Wall: Pluto Probe Spots Distant Dwarf Planet Quaoar. Space.com, August 31, 2016, accessed September 10, 2016 .
39. ^ New Horizons Spies a Kuiper Belt Companion. (No longer available online.) Johns Hopkins University Applied Physics Laboratory, August 31, 2016, archived from the original on November 15, 2017 ; accessed on December 12, 2017 (English).
40. ^ Wm. Robert Johnston: (50,000) Quaoar and Weywot . September 21, 2014. Retrieved March 4, 2019.