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2927 Alamosa, provisional designation 1981 TM, is a stony background asteroid from the central region of the asteroid belt, approximately 12 kilometers (7.5 miles) in diameter. The asteroid was discovered on 5 October 1981, by American astronomer Norman Thomas at Lowell's Anderson Mesa Station in Flagstaff, Arizona.[1] The S-type asteroid has a rotation period of 4.4 hours.[4] It was named after the U.S. town of Alamosa in Colorado.[2]

2927 Alamosa
Discovery [1]
Discovered byN. G. Thomas
Discovery siteAnderson Mesa Stn.
Discovery date5 October 1981
MPC designation(2927) Alamosa
Named after
Alamosa, Colorado[2]
(discoverer's birthplace)
1981 TM · 1936 OA
1975 EN2
main-belt[3] · (middle)[4]
Orbital characteristics[3]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 0
Observation arc82.26 yr (30,044 d)
Aphelion2.9605 AU
Perihelion2.1020 AU
2.5312 AU
4.03 yr (1,471 d)
0° 14m 40.92s / day
Physical characteristics
Mean diameter
11.83 km (calculated)[4]
4.3832 h[6]
0.20 (assumed)[4]

Orbit and classificationEdit

Alamosa is a non-family asteroid from the main belt's background population. It orbits the Sun in the central asteroid belt at a distance of 2.1–3.0 AU once every 4.03 years (1,471 days; semi-major axis of 2.53 AU). Its orbit has an eccentricity of 0.17 and an inclination of 17° with respect to the ecliptic.[3] It was first identified as 1936 OA at Heidelberg Observatory in 1936, extending the asteroid's observation arc by 45 years prior to its official discovery observation at Anderson Mesa.[1]


This minor planet was named after the U.S. town of Alamosa, Colorado, located in the San Luis Valley on the upper Rio Grande. The town is the birthplace of the discovering astronomer, Norman Thomas.[2] The official naming citation was published by the Minor Planet Center on 20 December 1983 (M.P.C. 8405).[10] Almosa is Spanish for cottonwood tree.

Physical characteristicsEdit

Alamosa has been characterized as a common S-type asteroid by Pan-STARRS' survey,[4][7] the Small Solar System Objects Spectroscopic Survey (S3OS2),[5][9] as well as in the SDSS-based taxonomy.[8] In the SMASS-like variant of the S3OS2 taxonomy, Alamosa is a K-type asteroid.[5][9]

In April and May 2012, a rotational lightcurve was obtained from photometric observations made at the Phillips Academy Observatory (I12). Lightcurve analysis gave a well-defined rotation period of 4.3832±0.0002 hours with a brightness variation of 0.26 in magnitude (U=3).[6] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 11.8 kilometers with an absolute magnitude of 12.0.[4]


  1. ^ a b c d "2927 Alamosa (1981 TM)". Minor Planet Center. Retrieved 18 November 2018.
  2. ^ a b c Schmadel, Lutz D. (2007). "(2927) Alamosa". Dictionary of Minor Planet Names – (2927) Alamosa. Springer Berlin Heidelberg. p. 241. doi:10.1007/978-3-540-29925-7_2928. ISBN 978-3-540-00238-3.
  3. ^ a b c d "JPL Small-Body Database Browser: 2927 Alamosa (1981 TM)" (2018-10-18 last obs.). Jet Propulsion Laboratory. Retrieved 18 November 2018.
  4. ^ a b c d e f g "LCDB Data for (2927) Alamosa". Asteroid Lightcurve Database (LCDB). Retrieved 18 November 2018.
  5. ^ a b c "Asteroid 2927 Alamosa". Small Bodies Data Ferret. Retrieved 18 November 2018.
  6. ^ a b Odden, Caroline; French, John; Briggs, John (October 2012). "Lightcurve Analysis for Four Asteroids". The Minor Planet Bulletin. 39 (4): 236–238. Bibcode:2012MPBu...39..236O. ISSN 1052-8091. Retrieved 4 May 2016.
  7. ^ a b 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 4 May 2016.
  8. ^ a b Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi:10.1051/0004-6361/200913322. Retrieved 18 November 2018.
  9. ^ a b c Lazzaro, D.; Angeli, C. A.; Carvano, J. M.; Mothé-Diniz, T.; Duffard, R.; Florczak, M. (November 2004). "S3OS2: the visible spectroscopic survey of 820 asteroids" (PDF). Icarus. 172 (1): 179–220. Bibcode:2004Icar..172..179L. doi:10.1016/j.icarus.2004.06.006. Retrieved 18 November 2018.
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 18 November 2018.

External linksEdit