725 Amanda

725 Amanda (prov. designation: A911 UQ or 1911 ND) is a dark background asteroid, approximately 22 kilometers (14 miles) in diameter, that is located in the central regions of the asteroid belt. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 21 October 1911.[1] The carbonaceous C-type asteroid (CSU/C0) has a short rotation period of 3.7 hours. It was named after Amanda Schorr, wife of German astronomer Richard Schorr (1867–1951).[3]

725 Amanda
Modelled shape of Amanda from its lightcurve
Discovery [1]
Discovered byJ. Palisa
Discovery siteVienna Obs.
Discovery date21 October 1911
Designations
(725) Amanda
PronunciationGerman: [aːˈmandaː][2]
Named after
Amanda Schorr, wife of Richard Schorr (1867–1951)
(German astronomer)[3]
A911 UQ · 2016 FH6
1911 ND
Orbital characteristics [4]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc104.58 yr (38,198 d)
Aphelion3.1422 AU
Perihelion2.0022 AU
2.5722 AU
Eccentricity0.2216
4.13 yr (1,507 d)
114.51°
0° 14m 20.04s / day
Inclination3.7902°
68.679°
323.36°
Physical characteristics
Mean diameter
3.749 h[12]
  • (145.0°, −63.0°) (λ1/β1)[6]
  • (320.0°, −70.0°) (λ2/β2)[6]

    Orbit and classification

    Amanda 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][7] It orbits the Sun in the central asteroid belt at a distance of 2.0–3.1 AU once every 4 years and 2 months (1,507 days; semi-major axis of 2.57 AU). Its orbit has an eccentricity of 0.22 and an inclination of 4° with respect to the ecliptic.[4] The body's observation arc begins at Vienna Observatory on 29 September 1915, almost four years after its official discovery observation.[1]

    Naming

    This minor planet was named after Amanda Schorr, wife of Richard Schorr (1867–1951), a German astronomer at Bergedorf Observatory, after whom asteroid 1235 Schorria and lunar crater Schorr were named. The asteroid's name was proposed by Palisa in 1913, on the occasion of the 24th meeting of the Astronomische Gesellschaft in Hamburg, Germany (AN 196, 139).[3] The naming was also mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 73).[3]

    Physical characteristics

    In the Tholen classification, Amanda's spectral type is closest to that of a carbonaceous C-type asteroid, yet also somewhat similar to a stony S-type with an "unusual" spectrum (CSU).[4] In the taxonomy by Barucci (1987), the asteroid is a dark C-type (C0).[6]

    Rotation period and poles
    Lightcurve-based 3D-model of Amanda

    A rotational lightcurve of Amanda was obtained from photometric observations by European astronomers at the La Silla Observatory before 1995. Lightcurve analysis gave a well-defined rotation period of 3.749 hours with a brightness variation of 0.35 magnitude (U=3).[12]

    In October 2010, French amateur astronomer Maurice Audejean (B92) determined a concurring period of (3.7431±0.0003) hours with an amplitude of (0.42±0.01) magnitude (U=3),[13] while in August 2018, a further observation by the TESS-team reported a period of (3.74301±0.00005) hours and an amplitude of (0.27±0.05) magnitude (U=2).[14]

    In 2016, a modeled lightcurve gave a sidereal period of 3.74311±0.00002 hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers, as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys (950). The study also determined two spin axes of (145.0°, −63.0°) and (320.0°, −70.0°) in ecliptic coordinates (λ, β).[15]

    Diameter and albedo

    According to the surveys carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), Amanda measures (20.49±0.28), (21.51±2.2) and (23.687±0.215) in diameter and its surface has an albedo of (0.082±0.003), (0.0721±0.017) and (0.068±0.015), respectively.[8][9][10][11]

    The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0824 and calculates a diameter of 21.56 kilometers based on an absolute magnitude of 11.66.[16] Alternative mean-diameters published by the WISE team include (19.53±6.07 km), (21.68±6.40 km), (23.286±0.149 km) and (30.73±4.85 km) with a corresponding albedo of (0.08±0.04), (0.055±0.037), (0.0509±0.0052) and (0.03±0.03).[6][16]

    References
    1. "725 Amanda (A911 UQ)". Minor Planet Center. Retrieved 15 June 2020.
    2. (German Names)
    3. Schmadel, Lutz D. (2007). "(725) Amanda". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 70. doi:10.1007/978-3-540-29925-7_726. ISBN 978-3-540-00238-3.
    4. "JPL Small-Body Database Browser: 725 Amanda (A911 UQ)" (2020-04-28 last obs.). Jet Propulsion Laboratory. Retrieved 15 June 2020.
    5. "Asteroid 725 Amanda – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 15 June 2020.
    6. "Asteroid 725 Amanda – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 15 June 2020.
    7. Zappalà, V.; Bendjoya, Ph.; Cellino, A.; Farinella, P.; Froeschle, C. (1997). "Asteroid Dynamical Families". NASA Planetary Data System: EAR-A-5-DDR-FAMILY-V4.1. Retrieved 15 June 2020.} (PDS main page)
    8. 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 15 June 2020. (online, AcuA catalog p. 153)
    9. 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 15 June 2020.
    10. Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System. Bibcode:2016PDSS..247.....M. Retrieved 15 June 2020.
    11. Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.
    12. di Martino, Mario; Dotto, E.; Barucci, M. A.; Fulchignoni, M.; Rotundi, A. (May 1994). "Photoelectric photometry of ten small and fast spinning asteroids". Icarus: 210–218. Bibcode:1994Icar..109..210D. doi:10.1006/icar.1994.1087. ISSN 0019-1035. Retrieved 15 June 2020.
    13. Behrend, Raoul. "Asteroids and comets rotation curves – (725) Amanda". Geneva Observatory. Retrieved 15 June 2020.
    14. Pál, András; Szakáts, Róbert; Kiss, Csaba; Bódi, Attila; Bognár, Zsófia; Kalup, Csilla; et al. (March 2020). "Solar System Objects Observed with TESS—First Data Release: Bright Main-belt and Trojan Asteroids from the Southern Survey". The Astrophysical Journal Supplement Series. 247 (1): 26. arXiv:2001.05822. Bibcode:2020ApJS..247...26P. doi:10.3847/1538-4365/ab64f0. ISSN 0067-0049.
    15. Hanuš, J.; Ďurech, J.; Brož, M.; Marciniak, A.; Warner, B. D.; Pilcher, F.; et al. (March 2013). "Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution". Astronomy and Astrophysics. 551: A67. arXiv:1301.6943. Bibcode:2013A&A...551A..67H. doi:10.1051/0004-6361/201220701. ISSN 0004-6361.
    16. "LCDB Data for (725) Amanda". Asteroid Lightcurve Database (LCDB). Retrieved 15 June 2020.
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