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1312 Vassar, provisional designation 1933 OT, is a carbonaceous Alauda asteroid from the outer region of the asteroid belt, approximately 30 kilometers in diameter. It was discovered on 27 July 1933, by Belgian–American astronomer George Van Biesbroeck at Yerkes Observatory in Wisconsin, United States.[11] The asteroid was named for the American Vassar College.

1312 Vassar
Discovery [1]
Discovered byG. van Biesbroeck
Discovery siteYerkes Obs.
Discovery date27 July 1933
MPC designation(1312) Vassar
Named after
Vassar College
(Vassar Observatory)[2]
1933 OT · 1944 QE
A908 CD
main-belt · (outer)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc83.67 yr (30,562 days)
Aphelion3.7605 AU
Perihelion2.4268 AU
3.0937 AU
5.44 yr (1,988 days)
0° 10m 51.96s / day
Physical characteristics
Dimensions27.56±6.84 km[5]
32.70±1.29 km[6]
36.28±1.1 km (IRAS:6)[7]
36.32 km (derived)[3]
7.93189±0.00001 h[8]
7.93190±0.00005 h[9]
7.932±0.002 h[a]
0.0643±0.004 (IRAS:6)[7]
0.0703 (derived)[3]
10.68[5] · 10.7[1][3] · 10.76±0.44[10] · 10.80[6]

Orbit and classificationEdit

Vassar is a member of the Alauda family (902),[4] a large family of typically bright carbonaceous asteroids and named after its parent body, 702 Alauda.[12]:23

It orbits the Sun in the outer main-belt at a distance of 2.4–3.8 AU once every 5 years and 5 months (1,988 days). Its orbit has an eccentricity of 0.22 and an inclination of 22° with respect to the ecliptic.[1] In 1908, it was first identified as A908 CD at Heidelberg Observatory. The body's observation arc begins with its official discovery observation at Yerkes in 1933.[11]

Physical characteristicsEdit

Rotation period and poleEdit

In November 2011, American amateur astronomer David Higgins obtained a rotational lightcurve of Vassar from photometric observations taken at the Hunters Hill Observatory (E14) in Australia. It gave a well-defined rotation period of 7.932 hours with a brightness variation of 0.35 magnitude (U=3).[a] In 2016, two modeled lightcurves were derived using data from the Lowell photometric database and other sources, giving a concurring period of 7.93189 and 7.93190 hours and a spin axis of (104.0°, −50°) and (251.0°, −23.0°) in ecliptic coordinates, respectively (U=n.a.).[8][9]

Diameter and albedoEdit

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, Vassar measures between 27.56 and 36.28 kilometers in diameter, and its surface has an albedo between 0.064 and 0.09.[5][6][7] The Collaborative Asteroid Lightcurve Link agrees with the results obtained by IRAS and derives an albedo of 0.0703 and a diameter of 36.32 kilometers with an absolute magnitude of 10.7.[3]


This minor planet was named by American astronomer Maud Worcester Makemson (1891–1977) after the U.S Vassar College (formerly: Vassar Female College), located in New York state. Makemson, who computed the asteroid's orbit, was a teacher at the private elite school and director of its Vassar College Observatory.[2] Naming citation was first published in The Names of the Minor Planets by Paul Herget in 1955 (H 120).[2]


  1. ^ a b Higgins (2011) web: rotation period 7.932±0.002 hours with a brightness amplitude of 0.35 mag. Summary figures for (1312) Vassar at Collaborative Asteroid Lightcurve Link (CALL) and Asteroid lightcurves at the Hunters Hill Observatory Higgins, D.J. (2011)


  1. ^ a b c d "JPL Small-Body Database Browser: 1312 Vassar (1933 OT)" (2017-03-30 last obs.). Jet Propulsion Laboratory. Retrieved 25 July 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1312) Vassar". Dictionary of Minor Planet Names – (1312) Vassar. Springer Berlin Heidelberg. p. 107. doi:10.1007/978-3-540-29925-7_1313. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f "LCDB Data for (1312) Vassar". Asteroid Lightcurve Database (LCDB). Retrieved 16 January 2017.
  4. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 7 November 2017.
  5. ^ a b c d 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 16 January 2017.
  6. ^ a b c d 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 16 January 2017.
  7. ^ a b c 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 16 January 2017.
  8. ^ a b Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics. 587: 6. arXiv:1601.02909. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573. Retrieved 16 January 2017.
  9. ^ a b Hanus, J.; Durech, J.; Oszkiewicz, D. A.; Behrend, R.; Carry, B.; Delbo, M.; et al. (February 2016). "New and updated convex shape models of asteroids based on optical data from a large collaboration network". Astronomy and Astrophysics. 586: 24. arXiv:1510.07422. Bibcode:2016A&A...586A.108H. doi:10.1051/0004-6361/201527441. Retrieved 16 January 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 16 January 2017.
  11. ^ a b "1312 Vassar (1933 OT)". Minor Planet Center. Retrieved 16 January 2017.
  12. ^ Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.

External linksEdit