(208996) 2003 AZ 84

from Wikipedia, the free encyclopedia
Asteroid
(208996) 2003 AZ 84
Image taken from 2003AZ84 by the Hubble Space Telescope
Image taken from 2003AZ 84 by the Hubble Space Telescope
Properties of the orbit ( animation )
Epoch:  April 27, 2019 ( JD 2,458,600.5)
Orbit type Plutino ,
"Distant Object"
Major semi-axis 39,362  AU
eccentricity 0.183
Perihelion - aphelion 32.17 AU - 46.554 AU
Inclination of the orbit plane 13.6 °
Length of the ascending node 252.2 °
Argument of the periapsis 15.2 °
Time of passage of the perihelion September 16, 2106
Sidereal period 246 a 11.5 M
Mean orbital velocity 0.04328 km / s
Physical Properties
Medium diameter
Dimensions 940 ± 40 × 766 ± 20 × 490 ± 16 km
Albedo
Rotation period 6.76 ± 0.02 h (0.282 d ) or
13.42 h (0.559 d )
Absolute brightness 3.54 - 3.78 mag
Spectral class C
B-V = 0.630 ± 0.010
VR = 0.410 ± 0.020
VI = 0.760 ± 0.020
BR = 1.370 ± 0.030
history
Explorer Chadwick A. Trujillo
Michael E. Brown
Eleanor F. Helin
Steven H. Pravdo
Kenneth J. Lawrence
Michael Hicks
Date of discovery January 13, 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.

(208996) 2003 AZ 84 is a large trans-Neptunian object in the Kuiper belt that is classified as Plutino . Because of its size, the asteroid is a dwarf planet candidate . It has a moon that is about a tenth the diameter of the parent asteroid.

discovery

2003 AZ 84 was discovered on January 13, 2003 by a team of astronomers consisting of Chad Trujillo , Mike Brown (both officially) and Eleanor "Glo" Helin , Steven Pravdo, Kenneth Lawrence and Michael Hicks, as part of Near Earth Asteroid Tracking on January 1, 2003 . 2 m Oschin Schmidt telescope discovered at Palomar Observatory ( California ). The discovery was announced on January 26, 2004; the asteroid was awarded in April 2009 by the IAU , the Minor Planet -number 208996 .

After its discovery, AZ 84 could be identified in 2003 on photos from March 19, 1996, which were taken as part of the Digitized Sky Survey project at the Palomar Observatory . This increased the observation period by 7 years, and the orbit could be calculated more precisely. Since then, the planetoid has been observed through various telescopes such as the Herschel and Spitzer space telescopes as well as earth-based telescopes. The last observation so far was carried out in January 2019 at the Vegaquattro observatory. (As of March 4, 2019)

properties

2003 AZ84 Orbit - Polar View
2003 Orbit AZ84 - Ecliptic View
2003 AZ 84 orbit (yellow above, blue below)
compared to that of Neptune and others.

Orbit

(208996) 2003 AZ 84 orbits the sun in 246.96 years on an elliptical orbit between 32.17  AU and 46.55 AU from its center. The orbital eccentricity is 0.183, the orbit is inclined 13.59 ° to the ecliptic . The planetoid is currently 44.44 AU from the Sun. It passed its point furthest from the sun ( aphelion ) in 1982 and will reach perihelion in 2106 ; the last passage of the perihelion should have taken place around the year 1859.

Simulations of the Deep Ecliptic Survey showed that in 2003 AZ 84 will never come closer than 31.6 AU to the sun in the next 10 million years and will therefore never cross the orbit of Neptune .

Both the Marc Buie ( DES ) and the Minor Planet Center classify AZ 84 as Plutino in 2003 , the latter also generally lists it as a “Distant Object”.

Size and shape

In 2017, after analyzing images from the Herschel and Spitzer space telescopes, the diameter was determined to be around 727 km, making the asteroid a size comparable to Varda . This value is based on an assumed albedo of 10.7% and an absolute brightness of 3.7 mag. In any case, the diameter should be between 600 and 800 km.

After four occultations between 2011 and 2014, a team of astronomers calculated in 2017 that 2003 AZ 84 probably has the shape of a three-axis ellipsoid (Jacobi type) with dimensions 940 × 766 × 490 km. having. This corresponds to an average diameter of 772 km. Like the dwarf planet Haumea , the planetoid has a pole-equator ratio of about 1: 2. The apparent magnitude of 2003 AZ 84 is 20.35  m . The light curve shows small albedo spots .

Since it can be assumed that 2003 AZ 84 is in hydrostatic equilibrium due to its size, despite its shape deviating far from spherical shape , it should meet the criteria for classification as a dwarf planet . Mike Brown assumes that 2003 AZ 84 is most likely a dwarf planet; Gonzalo Tancredi also accepts AZ 84 as a dwarf planet in 2003 , but does not propose to the IAU that it be officially recognized as such.

Determination of the diameter for 2003 AZ 84
year Dimensions km source
2007 685.8 +98.8−95.5 Stansberry et al. a.
2008 697.0 Tancredi
2010 686.0 Tancredi
2010 910.0 ± 60.0 Mueller et al. a.
2011 > 573.0 ± 21.0 Braga-Ribas et al. a.
2012 727.0 +61.9−66.5 Mommert et al. a.
2012 > 662.0 ± 50.0 Braga-Ribas et al. a.
2014 686.0 ± 14.0 Braga-Ribas et al. a.
2016 737.06 LightCurve DataBase
2017 772.0 ± 12.0
(940 ± 40 × 766 ± 20 × 490 ± 16) 		Dias-Oliveira u. a.
2018 747.0 Brown
The most precise determination is marked in bold .

rotation

Regarding the rotation period from 2003 AZ 84 , different research groups have come up with slightly different solutions by observing the light curve, which range from at least 6.71 ± 0.05 over 6.76 ± 0.02 to 6.79 ± 0.05 hours. Based on a rotation period of 6.76 hours rsp. 0.282 days it results that the planetoid performs 320244.2 self- rotations (“days”) in a 2003 AZ 84 year . According to another study from 2009, it would take about twice as long to do this with 13.42 hours, which would practically halve the number of 2003 AZ 84 days in its year with 161,315.3 revolutions. The latter variant, however, is considered to be rather unlikely, especially since the error rate is around 30% and the observation time at that time was insufficient.

surface

The spectrum and color are comparable to the Plutino (90482) Orcus . Both bodies show a flat, structureless spectrum in visible light and moderately strong water ice absorptions in the near infrared , although 2003 AZ 84 has a lower albedo. Both bodies also show weak absorption close to 2.3 μm, which could come from ammonia or methane ice . Assuming a diameter of 772 km, this results in a total surface of around 1,872,000 km².

A valley several kilometers in size was discovered on the surface from 2003 AZ 84 due to grazing star occultation .

moon

On February 22, 2007, the IAU announced the discovery of a moon that was tracked by Mike Brown and Terry-Ann Suer using images taken by the Hubble Space Telescope on December 2, 2005. It was found at a distance of 0.22 arc seconds from 2003 AZ 84 , with a difference in apparent magnitude of 5.0  m . Its diameter should be about 77 km. However, the moon has not yet been found, so it has not been possible to determine its mass .

The 2003 AZ 84 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 the 2003 AZ 84
equator 		Date of discovery
Date of publication
(208996) 2003 AZ 84
 772.0 100.0 ? - - - - January 13, 2003
January 26, 2003
(208996) 2003 AZ84 1
(208996 I) 		77.0 10.0 ? 7200 12.0 ? ? December 2, 2005
February 22, 2007

See also

Web links

Commons : (208996) 2003 AZ 84  - Collection of Pictures, Videos and Audio Files

Individual evidence

  1. ^ A b Marc W. Buie : Orbit Fit and Astrometric record for 208996 . 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. ↑ E. Lellouch et al. 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. ^ Wm. R. Johnston: List of Known Trans-Neptunian Objects . Johnston's Archives. October 7, 2018. Retrieved March 4, 2019.
  5. ↑ a b c d (208996) 2003 AZ84 at the IAU Minor Planet Center (English) Retrieved on March 4, 2019.
  6. ↑ v ≈ π * a / period (1 + sqrt (1-e²))
  7. ↑ a b c d e A. Dias-Oliveira u. a .: Study of the plutino object (208996) 2003 AZ84 from stellar occultations: size, shape and topographic features (PDF) . In: The Astronomical Journal . 154, No. 1, May 30, 2017. arxiv : 1705.10895 . doi : 10.3847 / 1538-3881 / aa74e9 .
  8. ↑ a b c M. Mommert u. a .: “TNOs are Cool”: A survey of the trans-Neptunian region. V. Physical characterization of 18 Plutinos using Herschel-PACS observations . In: Astronomy and Astrophysics . 541, no.A93 , February 16, 2012. arxiv : 1202.3657 . bibcode : 2012A & A ... 541A..93M . doi : 10.1051 / 0004-6361 / 201118562 .
  9. ↑ a b c J. Ortiz u. a .: Short-term rotational variability of eight KBOs from Sierra Nevada Observatory . In: Astronomy and Astrophysics . 447, No. 3, March 2006, pp. 1131-1144. bibcode : 2006A & A ... 447.1131O . doi : 10.1051 / 0004-6361: 20053572 .
  10. ↑ a b c (208996) 2003 AZ84 in the Small-Body Database of the Jet Propulsion Laboratory (English). Retrieved March 4, 2019. Template: JPL Small-Body Database Browser / Maintenance / Alt
  11. ↑ H. Boehnhardt et al. a .: Photometry of Transneptunian Objects for the Herschel Key Program `TNOs are Cool ' . In: Earth, Moon, and Planets . 114, No. 1-2, November 2014, pp. 35-57. bibcode : 2014EM & P..114 ... 35B . doi : 10.1007 / s11038-014-9450-x .
  12. ↑ P. Santos-Sanz et al. a .: New BVRI photometry results on KBOs from the ESO VLT . In: Astronomy and Astrophysics . 494, No. 2, December 24, 2008, pp. 693-706. arxiv : 0812.4525 . bibcode : 2009A & A ... 494..693S . doi : 10.1051 / 0004-6361: 20078301 .
  13. ↑ a b LCDB Data for 2003 AZ84 . MinorPlanetInfo. May 2013. Retrieved March 4, 2019.
  14. ↑ a b c 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. ↑ S. Tegler u. a .: Two Color Populations of Kuiper Belt and Centaur Objects and the Smaller Orbital Inclinations of Red Centaur Objects (PDF) . In: The Astronomical Journal . 152, No. 6, December 2016, p. 210, 13. bibcode : 2016AJ .... 152..210T . doi : 10.3847 / 0004-6256 / 152/6/210 .
  16. ↑ MPC : MPEC 2003-B27: 2003 AZ84 . IAU . January 26, 2003. Retrieved March 4, 2019.
  17. ↑ AstDyS-2: (208996) 2003AZ84 . Universita di Pisa. Retrieved March 4, 2019.
  18. ↑ a b Mike Brown : How many dwarf planets are there in the outer solar system? . CalTech . November 12, 2018. Retrieved March 4, 2019.
  19. ^ A b G. 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.
  20. ↑ 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. arxiv : astro-ph / 0702538 . bibcode : 2008ssbn.book..161S .
  21. ^ G. Tancredi, S. Favre: DPPH List . In: Dwarf Planets and Plutoid Headquarters, from Which are the dwarfs in the solar system? . September. Retrieved March 4, 2019.
  22. ↑ T. Mueller et al. a .: “TNOs are Cool”: A survey of the trans-Neptunian region I. Results from the Herschel Science Demonstration Phase (SDP) . In: Astronomy and Astrophysics . 518, No. L146, May 17, 2010, p. 5. arxiv : 1005.2923 . bibcode : 2010A & A ... 518L.146M . doi : 10.1051 / 0004-6361 / 201014683 .
  23. ↑ 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 .
  24. ↑ Braga-Ribas et al. a .: Stellar Occultations by Large TNOs on 2012: The February 3rd by (208996) 2003 AZ84, and the February 17th by (50000) Quaoar (October 2012) . In: American Astronomical Society, DPS meeting . 44, No. 402.01, October 2012. bibcode : 2012DPS .... 4440201B .
  25. ↑ Braga-Ribas et al. 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 .
  26. ^ S. Sheppard , D. Jewitt : Hawaii Kuiper Belt Variability Project: An Update . In: Earth, Moon, and Planets . 92, No. 1, June 2003, pp. 207-219. bibcode : 2003EM & P ... 92..207S . doi : 10.1023 / B: MOON.0000031943.12968.46 .
  27. ↑ A. Thirouin et al. a .: Short-term variability of a sample of 29 trans-Neptunian objects and Centaurs . In: Astronomy and Astrophysics . 522, No. A93, April 27, 2010, p. 43. arxiv : 1004.4841 . bibcode : 2010A & A ... 522A..93T . doi : 10.1051 / 0004-6361 / 200912340 .
  28. ↑ A. Delsanti et al. a .: Methane, ammonia, and their irradiation products at the surface of an intermediate-size KBO? A portrait of Plutino (90482) Orcus . In: Astronomy and Astrophysics . 627, No. 2, 2010, p. 1057. arxiv : 1006.4962 . bibcode : 2010A & A ... 520A..40D . doi : 10.1051 / 0004-6361 / 201014296 .
  29. ^ Wm. Robert Johnston: (208996) 2003 AZ84 . September 21, 2014. Retrieved March 4, 2019.
  30. ^ W. Grundy: 208996 (2003 AZ84) . Lowell Observatory . September 14, 2014. Accessed March 4, 2019.