Misplaced Pages

7641 Cteatus, provisional designation: 1986 TT₆, is a large Jupiter trojan from the Greek camp, approximately 70 kilometers (43 miles) in diameter. It was discovered on 5 October 1986, by Slovak astronomer Milan Antal at the Toruń Centre for Astronomy in Piwnice, Poland. The dark D-type asteroid is notably inclined and has longer-than-average rotation period of 27.8 hours. It belongs to the 50 largest Jupiter trojans. It was named from Greek mythology for Cteatus, the conjoined twin and father of Amphimachus.

Orbit and classification

Cteatus is a dark Jovian asteroid orbiting in the leading Greek camp at Jupiter's L₄ Lagrangian point, 60° ahead of its orbit in a 1:1 resonance (see Trojans in astronomy). It is also a non-family asteroid in the Jovian background population.

It orbits the Sun at a distance of 4.9–5.5 AU once every 11 years and 11 months (4,350 days; semi-major axis of 5.21 AU). Its orbit has an eccentricity of 0.05 and a notably high inclination of 35° with respect to the ecliptic. The asteroid was first observed as 1975 VT₅ at Crimea–Nauchnij in November 1975. The body's observation arc begins with its official discovery observation at the Toruń Centre.

Numbering and naming

This minor planet was numbered by the Minor Planet Center on 22 May 1997 (M.P.C. 29897). On 14 May 2021, the object was named by the Working Group for Small Bodies Nomenclature (WGSBN), after Cteatus from Greek mythology, who had a conjoined twin. His son Amphimachus was one of the leaders of the Elean contingent in the Trojan War.

Physical Characteristics

In the SDSS-based taxonomy, Cteatus is a dark D-type asteroid. It has also been characterized as a D-type by Pan-STARRS' survey. Its V–I color index of 0.98 agrees with that of most Jovian D-type asteroids.

Rotation period

In October 2009, a rotational lightcurve of Cteatus was obtained from photometric observations by Italian astronomer Stefano Mottola at the Calar Alto Observatory in Spain. Lightcurve analysis gave a well-defined rotation period of 27.770 hours with a brightness amplitude of 0.40 magnitude (U=3). While not being a slow rotator, its period is significantly longer than that of most larger Jupiter trojans, which have a spin rate of typically 10 hours. The body's relatively high brightness variation of 0.40 magnitude is also indicative of a non-spherical shape.

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, this asteroid measures between 68.97 and 75.28 kilometers in diameter and its surface has an albedo between 0.062 and 0.071. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0647 and a diameter of 68.89 kilometers based on an absolute magnitude of 9.4.

References

1. ^ "7641 (1986 TT6)". Minor Planet Center. Retrieved 10 June 2018.
2. ^ "WGSBN Bulletin Archive". Working Group for Small Bodies Nomenclature. 14 May 2021. Retrieved 16 May 2021. (Bulletin #1)
3. ^ "JPL Small-Body Database Browser: 7641 (1986 TT6)" (2018-05-20 last obs.). Jet Propulsion Laboratory. Retrieved 10 June 2018.
4. ^ "LCDB Data for (7641)". Asteroid Lightcurve Database (LCDB). Retrieved 10 June 2018.
5. "List of Jupiter Trojans". Minor Planet Center. 30 May 2018. Retrieved 10 June 2018.
6. ^ "Asteroid (7641) 1986 TT6". AstDyS-2, Asteroids – Dynamic Site. Retrieved 10 June 2018.
7. ^ 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. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 15 June 2018.
8. ^ 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)
9. ^ 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)
10. ^ Mottola, Stefano; Di Martino, Mario; Erikson, Anders; Gonano-Beurer, Maria; Carbognani, Albino; Carsenty, Uri; et al. (May 2011). "Rotational Properties of Jupiter Trojans. I. Light Curves of 80 Objects" (PDF). The Astronomical Journal. 141 (5): 32. Bibcode:2011AJ....141..170M. doi:10.1088/0004-6256/141/5/170.
11. ^ 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.
12. ^ Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi:10.1051/0004-6361/200913322. Retrieved 30 October 2019. (PDS data set)
13. "Asteroid (7641) 1986 TT6". Small Bodies Data Ferret. Retrieved 10 June 2018.
14. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 10 June 2018.

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Discovery Circumstances: Numbered Minor Planets (5001)-(10000) – Minor Planet Center
• 7641 Cteatus at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 7641 Cteatus at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Jupiter trojans (Greek camp)
• Discoveries by Milan Antal
• Named minor planets
• Astronomical objects discovered in 1986