925 Alphonsina

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925 Alphonsina
Discovery [1]
Discovered byJ. Comas Solà
Discovery siteFabra Obs.
Discovery date13 January 1920
MPC designation(925) Alphonsina
Named after
Alfonso X and Alfonso XIII
(Kings of Castile and Spain)
1920 GM · A902 ED
main-belt[1][2] · (middle)
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc115.98 yr (42,362 d)
Aphelion2.9130 AU
Perihelion2.4881 AU
2.7006 AU
4.44 yr (1,621 d)
0° 13m 19.56s / day
Physical characteristics
Mean diameter
54.34±3.4 km[5]
57.505±0.443 km[6]
58.000±4.841 km[7]
58±16 km[8]
58.06 km (taken)[9]
58.062 km[10]
59.2 km[11]
62.57±0.64 km[12]
63.52±11.11 km[13]
7.876 h[14]
7.87754±0.00005 h[8][15]
7.8780±0.0004 h[14]
7.879±0.001 h[16]
7.880±0.001 h[17]
7.883±0.002 h[a]
7.92 h[b]
Tholen = S[2]
SMASS = S[2][9] · S[19]
B–V = 0.850[2]
U–B = 0.454[2]

925 Alphonsina, provisional designation 1920 GM, is a stony Hansian asteroid from the central region of the asteroid belt, approximately 58 kilometers (36 miles) in diameter. It was discovered on 13 January 1920, by Catalan astronomer Josep Comas i Solà at the Fabra Observatory in Barcelona, Spain;[1] the S-type asteroid has a rotation period of 7.88 hours.[9] It was named for the Spanish Kings Alfonso X and Alfonso XIII.[20]

Orbit and classification[edit]

Together with asteroid 480 Hansa, Alphonsina is the largest member of the stony Hansa family (803),[3] a high-inclination family with more than a thousand known members.[4][21]:23

It orbits the Sun in the intermediate asteroid belt at a distance of 2.5–2.9 AU once every 4 years and 5 months (1,621 days; semi-major axis of 2.7 AU). Its orbit has an eccentricity of 0.08 and an inclination of 21° with respect to the ecliptic.[2] The asteroid was first observed as A902 ED at Heidelberg Observatory in March 1902. The body's observation arc begins ten days after its official discovery observation at Heidelberg.[1]

Physical characteristics[edit]

Alphonsina is a common, stony S-type asteroid in both the Tholen and SMASS classification.[2] Polarimetric observations in 2017 also characterized it as an S-type asteroid.[19]

Rotation period and pole[edit]

Since 1980, several rotational lightcurves of Alphonsina have been obtained from photometric observations with rotation periods between 7.876 and 7.92 hours (U=3/3/3/2/2).[14][16][17][a][b] The best-rated lightcurve by Alan Harris and James Whitney Young gave a period of 7.880 hours. The consolidated brightness amplitude is between 0.11 and 0.57 magnitude.[9][17]

In 2011, two modeled lightcurves using data from the Uppsala Asteroid Photometric Catalogue (UAPC) and from asteroidal occultation silhouettes gave a concurring period 7.87754 hours. The studies also determined a spin axis at (296.0°, 41.0°) and (294.0°, 41.0°) in ecliptic coordinates (λ, β), respectively.[8][15]

Diameter and albedo[edit]

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, Alphonsina measures between 54.34 and 63.52 kilometers in diameter and its surface has an albedo between 0.204 and 0.2786.[5][6][7][10][12][13][18]

Combined Plot - Light Curve Inversion model (DAMIT 301) and Multi-chord Occultation.

In 2003, stellar occultation measured a diameter of 59.2 kilometres and deduced an albedo of 0.218,[11] while the modelling of asteroid occultation silhouettes gave a diameter of 58 kilometres.[8] The asteroid has been observed in stellar occultations 8 times since 2003.[22]

The Collaborative Asteroid Lightcurve Link adopts Petr Pravec's revised WISE data, that is, an albedo of 0.2266 and a diameter of 58.06 kilometers based on an absolute magnitude of 8.41.[9]


This minor planet was named in honor of the Iberian Kings, Alfonso X (1221–1284) and Alfonso XIII (1886–1941), King of Castile and Spain, respectively; the original citation from 1920, mentions, that the 13th century king inspired the field of astronomy in the Middle Ages, and, that the latter king was a great enthusiast of the scientific development in Spain. It also mentions that the King of Spain approved the naming of the asteroid (AN 211, 223).[20]


  1. ^ a b Hamanowa (2011) web: rotation period 7.883±0.002 hours with a brightness amplitude of 0.30 mag. Summary figures for (925) Alphonsina at the LCDB.
  2. ^ a b Hanslmeier (1980): rotation period for (925) Alphonsina of 7.92 hours with a brightness amplitude of 0.18 mag. Quality Code of 2. Summary figures at the LCDB.


  1. ^ a b c d "925 Alphonsina (1920 GM)". Minor Planet Center. Retrieved 4 April 2018.
  2. ^ a b c d e f g h i "JPL Small-Body Database Browser: 925 Alphonsina (1920 GM)" (2018-02-27 last obs.). Jet Propulsion Laboratory. Retrieved 4 April 2018.
  3. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 4 April 2018.
  4. ^ a b Hergenrother, C. W.; Larson, S. M.; Spahr, T. B. (September 1996). "The Hansa Family: A New High-Inclination Asteroid Family". American Astronomical Society. 28: 1097. Bibcode:1996DPS....28.1007H.
  5. ^ a b c d 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. Bibcode:2004PDSS...12.....T.
  6. ^ a b c 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.
  7. ^ a b c d Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; 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.
  8. ^ a b c d Durech, Josef; Kaasalainen, Mikko; Herald, David; Dunham, David; Timerson, Brad; et al. (August 2011). "Combining asteroid models derived by lightcurve inversion with asteroidal occultation silhouettes". Icarus. 214 (2): 652–670. arXiv:1104.4227. Bibcode:2011Icar..214..652D. doi:10.1016/j.icarus.2011.03.016.
  9. ^ a b c d e f "LCDB Data for (925) Alphonsina". Asteroid Lightcurve Database (LCDB). Retrieved 4 April 2018.
  10. ^ a b c d Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026.
  11. ^ a b c d Shevchenko, Vasilij G.; Tedesco, Edward F. (September 2006). "Asteroid albedos deduced from stellar occultations". Icarus. 184 (1): 211–220. Bibcode:2006Icar..184..211S. doi:10.1016/j.icarus.2006.04.006.
  12. ^ a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; 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.
  13. ^ a b c d Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8.
  14. ^ a b c Behrend, Raoul. "Asteroids and comets rotation curves – (925) Alphonsina". Geneva Observatory. Retrieved 4 April 2018.
  15. ^ a b Hanus, J.; Durech, J.; Broz, M.; Warner, B. D.; Pilcher, F.; et al. (June 2011). "A study of asteroid pole-latitude distribution based on an extended set of shape models derived by the lightcurve inversion method". Astronomy and Astrophysics. 530: 16. arXiv:1104.4114. Bibcode:2011A&A...530A.134H. doi:10.1051/0004-6361/201116738.
  16. ^ a b Alton, Kevin B. (July 2017). "CCD Lightcurves for Main-belt Asteriods 423 Diotima and 925 Alphonsina". The Minor Planet Bulletin. 44 (3): 188–189. Bibcode:2017MPBu...44..188A. ISSN 1052-8091.
  17. ^ a b c d Harris, A. W.; Young, J. W. (October 1989). "Asteroid lightcurve observations from 1979-1981". Icarus. 81 (2): 314–364. Bibcode:1989Icar...81..314H. doi:10.1016/0019-1035(89)90056-0. ISSN 0019-1035.
  18. ^ a b Mainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Wright, E.; et al. (August 2011). "Thermal Model Calibration for Minor Planets Observed with Wide-field Infrared Survey Explorer/NEOWISE". The Astrophysical Journal. 736 (2): 9. Bibcode:2011ApJ...736..100M. CiteSeerX doi:10.1088/0004-637X/736/2/100.
  19. ^ a b Belskaya, I. N.; Fornasier, S.; Tozzi, G. P.; Gil-Hutton, R.; Cellino, A.; Antonyuk, K.; et al. (March 2017). "Refining the asteroid taxonomy by polarimetric observations". Icarus. 284: 30–42. Bibcode:2017Icar..284...30B. doi:10.1016/j.icarus.2016.11.003.
  20. ^ a b Schmadel, Lutz D. (2007). "(925) Alphonsina". Dictionary of Minor Planet Names – (925) Alphonsina. Springer Berlin Heidelberg. p. 82. doi:10.1007/978-3-540-29925-7_926. ISBN 978-3-540-00238-3.
  21. ^ Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.
  22. ^ "Asteroid Data Sets". sbn.psi.edu. Retrieved 27 May 2018.

External links[edit]