771 Libera

771 Libera, provisional designation 1913 TO, is a metallic asteroid from the middle region of the asteroid belt, about 29 kilometers in diameter. It was discovered by Austrian astronomer Joseph Rheden at the Vienna Observatory in Austria, on 21 November 1913.[12]

771 Libera
Modelled shape of Libera from its lightcurve
Discovery [1]
Discovered byJ. Rheden
Discovery siteVienna Observatory
Discovery date21 November 1913
Designations
(771) Libera
PronunciationClassically /ˈlɪbərə/[2]
Named after
friend of discoverer[3]
1913 TO · 1958 HA
main-belt · (middle) [4]
Orbital characteristics [1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc101.75 yr (37166 d)
Aphelion3.3092 AU (495.05 Gm)
Perihelion1.9937 AU (298.25 Gm)
2.6514 AU (396.64 Gm)
Eccentricity0.24808
4.32 yr (1576.9 d)
268.14°
0° 13m 41.844s / day
Inclination14.936°
218.19°
227.36°
Earth MOID1.03684 AU (155.109 Gm)
Jupiter MOID2.11238 AU (316.008 Gm)
TJupiter3.299
Physical characteristics
Dimensions29.38±1.1 km (IRAS:6)[1][5]
28.91±0.72 km[6]
29.000±1.403 km[7]
29.33 km (derived)[4]
Mean radius
14.69±0.55 km
5.892±0.002 h[8]
5.92 h[9]
5.886±0.001 h[10]
5.89±0.05 h[10]
5.890±0.001 h[11]
5.892 h (0.2455 d)[1]
0.1303±0.010 (IRAS:6)[1] [5]
0.141±0.008[6]
0.1299±0.0158[7]
0.1226 (SIMPS)[4]
B–V = 0.687
U–B = 0.300
X (Tholen), X (SMASS), X [4]
10.49[1]

    Description
    Lightcurve-based 3-D model of Libera

    The metallic X-type asteroid orbits the Sun at a distance of 2.0–3.3 AU once every 4 years and 4 months (1,576 days). Its orbit shows an eccentricity of 0.25 and is tilted by 15 degrees to the plane of the ecliptic. A photometric observation of the asteroid's light-curve performed at the Palmer Divide Observatory during 1999 rendered a rotation period of 5.892±0.002 hours with a brightness variation of 0.57 magnitude.[8] The result concurs with several previous observations, including a photometric analysis conducted over a twelve-year interval.[9][10][11]

    According to the surveys carried out by the Infrared Astronomical Satellite, IRAS, the Japanese Akari satellite, and the U.S. Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid's surface has an albedo of 0.13 and 0.14, respectively, while the Collaborative Asteroid Lightcurve Link publishes a slightly lower figure of 0.12 from an alternative result of the Supplemental IRAS Minor Planet Survey.[4]

    The minor planet was named by Mrs. Hedwig Rheden in honor of a friend of the discoverer.[3]

    References
    1. "JPL Small-Body Database Browser: 771 Libera (1913 TO)" (2015-08-30 last obs.). Jet Propulsion Laboratory. Retrieved 5 May 2016.
    2. Noah Webster (1884) A Practical Dictionary of the English Language
    3. Schmadel, Lutz D. (2003). "(771) Libera". Dictionary of Minor Planet Names – (771) Libera. Springer Berlin Heidelberg. p. 73. doi:10.1007/978-3-540-29925-7_772. ISBN 978-3-540-29925-7.
    4. "LCDB Data for (771) Libera". Asteroid Lightcurve Database (LCDB). Retrieved 4 January 2016.
    5. 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.
    6. 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)
    7. 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. Retrieved 4 January 2016.
    8. Warner, B. (March 2000). "Asteroid Photometry at the Palmer Divide Observatory". The Minor Planet Bulletin. 27: 4–6. Bibcode:2000MPBu...27....4W. Retrieved 4 January 2016.
    9. Binzel, R. P. (October 1987). "A photoelectric survey of 130 asteroids". Icarus. 72 (1): 135–208. Bibcode:1987Icar...72..135B. doi:10.1016/0019-1035(87)90125-4. ISSN 0019-1035. Retrieved 4 January 2016.
    10. Behrend, Raoul. "Asteroids and comets rotation curves – (771) Libera". Geneva Observatory. Retrieved 4 January 2016.
    11. Marciniak, A.; Michalowski, T.; Hirsch, R.; Behrend, R.; Bernasconi, L.; Descamps, P.; et al. (December 2009). "Photometry and models of selected main belt asteroids. VII. 350 Ornamenta, 771 Libera, and 984 Gretia". Astronomy and Astrophysics. 508 (3): 1503–1507. Bibcode:2009A&A...508.1503M. doi:10.1051/0004-6361/200912741. Retrieved 4 January 2016.
    12. "771 Libera (1913 TO)". Minor Planet Center. Retrieved 4 January 2016.

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