1268 Libya

1268 Libya, provisional designation 1930 HJ, is a dark Hildian asteroid from the outer regions of the asteroid belt, approximately 95 kilometers in diameter. It was discovered on 29 April 1930, by South African astronomer Cyril Jackson at the Union Observatory in Johannesburg, South Africa.[3] The asteroid was named for the country Libya.[2]

1268 Libya
Discovery [1]
Discovered byC. Jackson
Discovery siteJohannesburg Obs.
Discovery date29 April 1930
Designations
(1268) Libya
Named after
Libya (country) [2]
1930 HJ · 1929 EA
1930 KN
main-belt · (outer) [1]
Hilda [3][4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc87.09 yr (31,811 days)
Aphelion4.3787 AU
Perihelion3.5686 AU
3.9737 AU
Eccentricity0.1019
7.92 yr (2,893 days)
157.54°
0° 7m 27.84s / day
Inclination4.4272°
351.00°
119.43°
Jupiter MOID0.7451 AU
Physical characteristics
Dimensions93.44±1.42 km[5]
94.10±2.3 km[6]
96.708±0.848 km[7]
14.05 h[8]
14.05008 h[9]
0.043±0.003[7]
0.0449±0.002[6]
0.046±0.002[5]
Tholen = P [1][4]
B–V = 0.663[1]
U–B = 0.228[1]
9.12[1][4][5][6] · 9.19±0.33[10]

    Orbit and classification

    Libya belongs to the dynamical Hilda group of asteroids, which reside in, or closely inside the 3:2 orbital resonance with the giant planet Jupiter at 4.0 AU.[3][4] However, the asteroid belongs to the background population as it is not a member of any known asteroid family within the Hildian dynamical group.[11]

    Libya orbits the Sun in the outer main-belt at a distance of 3.6–4.4 AU once every 7 years and 11 months (2,893 days). Its orbit has an eccentricity of 0.10 and an inclination of 4° with respect to the ecliptic.[1] The asteroid was first identified as 1929 EA at Uccle Observatory in March 1929, and its observation arc begins with its official discovery observation at Johannesburg in 1930.[3]

    Physical characteristics

    In the Tholen classification, Libya is a primitive P-type asteroid.[1]

    Rotation period

    In June 1994, a rotational lightcurve of Libya was obtained from photometric observations by Swedish astronomer Mats Dahlgren (see 6945) at ESO's La Silla Observatory using the Dutch 0.9-metre Telescope. Lightcurve analysis gave a well-defined rotation period of 14.05 hours with a brightness variation of 0.08 magnitude (U=3).[8] In October 2011, observations by French amateur astronomer René Roy also gave a period of 14.05 hours and a low amplitude of 0.06 magnitude (U=n.a.). A low brightness amplitude typically indicates that the body has a spheroidal rather than an elongated or irregular 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, Libya measures between 93.44 and 96.708 kilometers in diameter and its surface has an albedo between 0.043 and 0.046.[5][6][7]

    The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0449 and a diameter of 94.10 kilometers based on an absolute magnitude of 9.12.[4]

    Naming

    This minor planet was named after the North African country of Libya, bordering the Mediterranean Sea. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 116).[2]

    References
    1. "JPL Small-Body Database Browser: 1268 Libya (1930 HJ)" (2017-06-02 last obs.). Jet Propulsion Laboratory. Retrieved 19 September 2017.
    2. Schmadel, Lutz D. (2007). "(1268) Libya". Dictionary of Minor Planet Names – (1268) Libya. Springer Berlin Heidelberg. p. 105. doi:10.1007/978-3-540-29925-7_1269. ISBN 978-3-540-00238-3.
    3. "1268 Libya (1930 HJ)". Minor Planet Center. Retrieved 19 September 2017.
    4. "LCDB Data for (1268) Libya". Asteroid Lightcurve Database (LCDB). Retrieved 19 September 2017.
    5. 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)
    6. 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.
    7. Grav, T.; Mainzer, A. K.; Bauer, J.; Masiero, J.; Spahr, T.; McMillan, R. S.; et al. (January 2012). "WISE/NEOWISE Observations of the Hilda Population: Preliminary Results". The Astrophysical Journal. 744 (2): 15. arXiv:1110.0283. Bibcode:2012ApJ...744..197G. doi:10.1088/0004-637X/744/2/197. Retrieved 19 September 2017.
    8. Dahlgren, M.; Lahulla, J. F.; Lagerkvist, C.-I.; Lagerros, J.; Mottola, S.; Erikson, A.; et al. (June 1998). "A Study of Hilda Asteroids. V. Lightcurves of 47 Hilda Asteroids". Icarus. 133 (2): 247–285. Bibcode:1998Icar..133..247D. doi:10.1006/icar.1998.5919. Retrieved 19 September 2017.
    9. Behrend, Raoul. "Asteroids and comets rotation curves – (1268) Libya". Geneva Observatory. Retrieved 19 September 2017.
    10. 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. Retrieved 19 September 2017.
    11. "Asteroid 1268 Libya – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 29 October 2019.

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