1236 Thaïs

1236 Thaïs /ˈθeɪ.ɪs/ (prov. designation: 1931 VX) is a dark background asteroid from the inner regions of the asteroid belt. The rare T-type asteroid has a notably long rotation period of 72 hours and measures approximately 18 kilometers (11 miles). It was discovered on 6 November 1931, by Soviet astronomer Grigory Neujmin at Simeiz Observatory on the Crimean peninsula, and named after the ancient Greek prostitute Thaïs.[3][4]

1236 Thaïs
Modelled shape of Thaïs from its lightcurve
Discovery [1]
Discovered byG. Neujmin
Discovery siteSimeiz Obs.
Discovery date6 November 1931
Designations
(1236) Thaïs
Pronunciation/ˈθeɪ.ɪs/[2]
Named after
Thaïs (ancient Greek hetaira)[3]
1931 VX · 1957 LQ
1964 JH · 1965 WA
Orbital characteristics [1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc84.57 yr (30,888 days)
Aphelion3.0192 AU
Perihelion1.8455 AU
2.4323 AU
Eccentricity0.2413
3.79 yr (1,386 days)
216.42°
0° 15m 35.28s / day
Inclination13.169°
48.618°
305.94°
Physical characteristics
Mean diameter
14.43±4.75 km[7]
17.18±4.94 km[8]
19.163±1.790 km[9]
20.07±0.41 km[10]
22.34±1.3 km (IRAS:7)[11]
72 h[12]
0.0599±0.007 (IRAS:7)[11]
0.075±0.004[10]
0.0813±0.0159[9]
0.10±0.07[8]
0.11±0.11[7]
Tholen = T [1][13]
B–V = 0.785[1]
U–B = 0.383[1]
11.91[8]
11.93[1][13][7][9][10][11]

    Orbit and classification

    Thaïs is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[5][6] It orbits the Sun in the inner main-belt at a distance of 1.8–3.0 AU once every 3 years and 9 months (1,386 days). Its orbit has an eccentricity of 0.24 and an inclination of 13° with respect to the ecliptic.[1] The body's observation arc begins at the discovering observatory, one month after its official discovery observation, as no precoveries were taken, and no prior identifications were made.[4]

    Naming

    This minor planet was named after Thaïs, the famous Greek hetaera (ancient prostitute), who lived during the time of Alexander the Great (356–323 BC) and accompanied him on his campaigns. It is also the name of the protagonist in the novel Thaïs by French poet Anatole France.[3]

    Physical characteristics

    Spectral type

    Thaïs is a dark and reddish T-type asteroid in the Tholen taxonomic scheme.[1] It has also been classified as a L-type asteroid by PanSTARRS large-scale survey.[13]

    Rotation period

    As of 2017, the only existing lightcurve of Thaïs gives a rotation period of 72 hours with a brightness variation of 0.08 magnitude (U=1). The fragmentary light curve was obtained by Austrian astronomers from photoelectric observations in the early 1980s.[12] While not being a slow rotator, it has a significantly longer-than average rotation period, if future observations confirm the tentative results.

    Diameter and albedo

    According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Thaïs measures between 14.43 and 22.34 kilometers in diameter, and its surface has an albedo between 0.06 and 0.11.[7][8][9][10][11] The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0599 and a diameter of 22.34 kilometers based on an absolute magnitude of 11.93.[13]

    References
    1. "JPL Small-Body Database Browser: 1236 Thais (1931 VX)" (2016-06-04 last obs.). Jet Propulsion Laboratory. Retrieved 25 January 2017.
    2. "Thaïs". Dictionary.com Unabridged. Random House.
    3. Schmadel, Lutz D. (2007). "(1236) Thaïs". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 103. doi:10.1007/978-3-540-29925-7_1237. ISBN 978-3-540-00238-3.
    4. "1236 Thais (1931 VX)". Minor Planet Center. Retrieved 25 January 2017.
    5. "Asteroid 1236 Thais – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 15 March 2020.
    6. "Asteroid 1236 Thais". Small Bodies Data Ferret. Retrieved 15 March 2020.
    7. Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. Retrieved 25 January 2017.
    8. Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 25 January 2017.
    9. Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
    10. 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. Retrieved 17 October 2019. (online, AcuA catalog p. 153)
    11. Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 22 October 2019.
    12. Schober, H. J.; Schroll, A. (April 1983). "Rotation properties of the high-numbered asteroids 1236 Thais and 1317 Silvretta". Astronomy and Astrophysics. 120 (1): 106–108. Bibcode:1983A&A...120..106S. ISSN 0004-6361. Retrieved 25 January 2017.
    13. "LCDB Data for (1236) Thaïs". Asteroid Lightcurve Database (LCDB). Retrieved 25 January 2017.
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