1173 Anchises

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1173 Anchises
001173-asteroid shape model (1173) Anchises.png
Shape model of Anchises from its lightcurve
Discovery[1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date17 October 1930
Designations
(1173) Anchises
Pronunciation/æŋˈkaɪsiːz/[7]
Named after
Anchises (Greek mythology)[2]
1930 UB
Minor planet category
Jupiter trojan[1][3][4]
Trojan[5][6] · background[6]
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc87.60 yr (31,997 d)
Aphelion6.0232 AU
Perihelion4.5678 AU
5.2955 AU
Eccentricity0.1374
12.19 yr (4,451 d)
184.44°
0° 4m 51.24s / day
Inclination6.9202°
283.91°
40.496°
Jupiter MOID0.4727 AU
TJupiter2.9670
Physical characteristics
Dimensions170 km × 121 km × 121 km[8]
Mean diameter
99.55±0.85 km[9]
120.49±2.91 km[10]
126.27±10.7 km[11]
136±18 km[8]
11.595±0.002 h[12][a]
11.596±0.005 h[13][b]
11.60 h[14]
0.0308±0.006[11]
0.035±0.002[10]
0.050±0.009[9]
P (Tholen)[3][4][15]
D (Barucci)[15]
U–B = 0.266±080[3]
B–V = 0.770±0.050[16]
V–R = 0.450±0.030[16]
V–I = 0.950±0.026[4]
Absolute magnitude (H)
8.89[3][4][9][10][11]
9.14±0.31[17]
9.35[14]

1173 Anchises /æŋˈkaɪsiːz/ is an unusually elongated Jupiter Trojan from the Trojan camp, approximately 124 kilometers (77 miles) in diameter. It was discovered on 17 October 1930, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany, and was the 9th such body to be discovered.[1][8]: 2  The primitive P-type asteroid belongs to the largest Jupiter trojans, has an unusually smooth surface texture, the lowest spectral slope of all members of the Trojan camp, and a rotation period of 11.6 hours.[4] It was named after Anchises from Greek mythology.[2]

Orbit and classification[]

Anchises is a primitive Jovian asteroid orbiting in the trailing Trojan camp at Jupiter's L5 Lagrangian point, 60° behind its orbit in a 1:1 resonance (see Trojans in astronomy). It is also a non-family asteroid of the Jovian background population.[6][15]

It orbits the Sun at a distance of 4.6–6.0 AU once every 12 years and 2 months (4,451 days; semi-major axis of 5.3 AU). Its orbit has an eccentricity of 0.14 and an inclination of 7° with respect to the ecliptic.[3] Up to the year 2200, its closest approach to any major planet will be on 3 February 2120, when it will still be 2.669 AU (399,300,000 km; 248,100,000 mi) from Jupiter.[18] The body's observation arc begins at Heidelberg with its official discovery observation in October 1930.[1]

Naming[]

This minor planet was named after Anchises from Greek mythology. He is the father of the Trojan hero Aeneas after whom 1172 Äneas was named. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 109).[2]

Physical characteristics[]

In the Tholen classification, Anchises is a primitive P-type asteroid, a common spectral type among the Jupiter trojans.[3][4] It has the lowest spectral slope (i.e. flattest spectral response curve, thus most neutral color) among all members of the Trojan camp.[19] In the Barucci taxonomy, it has been characterized as a carbonaceous C-type asteroid (C0).[15]

Rotation period[]

In Summer 1986, the first photometric observations of Anchises were taken with the 0.9-meter telescope at the Cerro Tololo Observatory in Chile. Lightcurve analysis gave a well defined rotation period of 11.60 hours with a notably wide brightness variation of 0.57 magnitude (U=3).[14]

Between January 2016, and December 2017, three more rotational lightcurves were obtained by American photometrist Robert Stephens at the Center for Solar System Studies in California. They gave a concurring period of 11.595,[a] 11.596[b] and 11.599 hours[c] with an amplitude between 0.34 and 0.73 magnitude (U=3/3-/3?).[12][13] A high brightness amplitude is indicative for a non-spherical, elongated shape (see below).

Diameter and albedo[]

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, and astronomers revisiting the data from these three space-based telescopes, Anchises measures between 99.55 and 136 kilometers in diameter and its surface has an albedo between 0.0308 and 0.050.[8][9][10][11] The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is an albedo of 0.0308 and a diameter of 126.27 kilometers based on an absolute magnitude of 8.89.[4]

This makes it the 7th largest Jupiter trojan only according to IRAS (126 km), and would be at least 6th should the size indeed prove to be 136 km or more, while it is much smaller and a few places further down the list according to the NEOWISE survey catalog (<100 km). One of the reasons for the large discrepancies in diameter estimates is possibly related to the results being derived from single-epoch observations of the asteroid, which is known for its large brightness variations (see above).[8]

100+ largest Jupiter trojans

Shape and surface[]

In 2012, an international collaboration revisited the WISE, IRAS and Akari observational data. As already suggested by the body's high brightness amplitude, the astronomers found that Anchises is significantly elongated, with best-fit dimensions of 170 km × 121 km × 121 km, which corresponds to a mean diameter of 136+18
−11 kilometers.[8] Due to a small phase coefficient and a lack of any noticeable opposition effect, astronomers at Cerro Tololo concluded that this Jupiter trojan asteroid possesses an unusually smooth surface texture – far less rough than the great majority of asteroids.[14] In case the surface of Anchises consist of bare rock, with high thermal inertia, the body's true diameter could be significantly greater than the estimated 136 kilometers, the study concludes.[8]

Notes[]

  1. ^ Jump up to: a b Lightcurve plot of (1173) Anchises by Robert Stephens (Feb 2016). Rotation period 11.595±0.002 hours with a brightness amplitude of 0.61±0.02 mag. Quality code of 3. Summary figures at the Center for Solar System Studies (CS3) website and at the LCDB
  2. ^ Jump up to: a b Lightcurve plot of (1173) Anchises by Robert Stephens (Dec 2016). Rotation period 11.596±0.005 hours with a brightness amplitude of 0.73±0.04 mag. Quality code of 3-. Summary figures at the Center for Solar System Studies (CS3) website and at the LCDB
  3. ^ Lightcurve plot of (1173) Anchises by Robert Stephens (2017). Rotation period 11.599±0.001 hours with a brightness amplitude of 0.34±0.02 mag. Quality code of 3. Summary figures at the Center for Solar System Studies (CS3) website and at the LCDB

References[]

  1. ^ Jump up to: a b c d "1173 Anchises (1930 UB)". Minor Planet Center. Retrieved 12 June 2018.
  2. ^ Jump up to: a b c Schmadel, Lutz D. (2007). "(1173) Anchises". Dictionary of Minor Planet Names – (1173) Anchises. Springer Berlin Heidelberg. p. 99. doi:10.1007/978-3-540-29925-7_1174. ISBN 978-3-540-00238-3.
  3. ^ Jump up to: a b c d e f g "JPL Small-Body Database Browser: 1173 Anchises (1930 UB)" (2018-05-25 last obs.). Jet Propulsion Laboratory. Retrieved 12 June 2018.
  4. ^ Jump up to: a b c d e f g "LCDB Data for (1173) Anchises". Asteroid Lightcurve Database (LCDB). Retrieved 12 June 2018.
  5. ^ "List of Jupiter Trojans". Minor Planet Center. 30 May 2018. Retrieved 12 June 2018.
  6. ^ Jump up to: a b c "Asteroid (1173) Anchises – Proper elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 5 June 2018.
  7. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  8. ^ Jump up to: a b c d e f g Horner, J.; Müller, T. G.; Lykawka, P. S. (July 2012). "(1173) Anchises – thermophysical and dynamical studies of a dynamically unstable Jovian Trojan". Monthly Notices of the Royal Astronomical Society. 423 (3): 2587–2596. arXiv:1204.1388. Bibcode:2012MNRAS.423.2587H. doi:10.1111/j.1365-2966.2012.21067.x. S2CID 119307083.
  9. ^ Jump up to: a b c d Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. arXiv:1209.1549. Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. S2CID 119101711. (online catalog)
  10. ^ Jump up to: a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
  11. ^ Jump up to: a b c d Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 15 June 2018.
  12. ^ Jump up to: a b Stephens, Robert D.; Coley, Daniel R.; French, Linda M. (July 2016). "A Report from the L5 Trojan Camp - Lightcurves of Jovian Trojan Asteroids from the Center for Solar System Studies". The Minor Planet Bulletin. 43 (3): 265–270. Bibcode:2016MPBu...43..265S. ISSN 1052-8091. Retrieved 3 March 2018.
  13. ^ Jump up to: a b Stephens, Robert D. (April 2017). "Lightcurve Analysis of Trojan Asteroids at the Center for Solar System Studies 2016 October - December". The Minor Planet Bulletin. 44 (2): 123–125. Bibcode:2017MPBu...44..123S. ISSN 1052-8091. PMC 7243949. PMID 32455395. Retrieved 3 March 2018.
  14. ^ Jump up to: a b c d French, L. M. (November 1987). "Rotation properties of four L5 Trojan asteroids from CCD photometry". Icarus. 72 (2): 325–341.MIT–supportedresearch. Bibcode:1987Icar...72..325F. doi:10.1016/0019-1035(87)90178-3. ISSN 0019-1035. Retrieved 3 March 2018.
  15. ^ Jump up to: a b c d "Asteroid 1173 Anchises". Small Bodies Data Ferret. Retrieved 12 June 2018.
  16. ^ Jump up to: a b Chatelain, Joseph P.; Henry, Todd J.; French, Linda M.; Winters, Jennifer G.; Trilling, David E. (June 2016). "Photometric colors of the brightest members of the Jupiter L5 Trojan cloud". Icarus. 271: 158–169. Bibcode:2016Icar..271..158C. doi:10.1016/j.icarus.2016.01.026. Retrieved 12 June 2018.
  17. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. S2CID 53493339.
  18. ^ Horizons output. "Observer Table for Asteroid 1173 Anchises (1930 UB)". Retrieved 4 April 2012. (Observer Location:@Jupiter)
  19. ^ Fornasier, S.; Dotto, E.; Hainaut, O.; Marzari, F.; Boehnhardt, H.; De Luise, F.; et al. (October 2007). "Visible spectroscopic and photometric survey of Jupiter Trojans: Final results on dynamical families". Icarus. 190 (2): 622–642. arXiv:0704.0350. Bibcode:2007Icar..190..622F. doi:10.1016/j.icarus.2007.03.033. S2CID 12844258.

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