Astronomy:2975 Spahr

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2975 Spahr
Discovery [1]
Discovered byH. Potter
A. Lokalov
Discovery siteCerro El Roble Stn.
Discovery date8 January 1970
Designations
(2975) Spahr
Named afterTimothy Spahr [1]
(MPC director)
1970 AF1 · 1957 HU
1967 GH · 1970 AK1
1970 CB · 1978 PF4
Minor planet categorymain-belt [1][2] · (inner)
background [3][4] · Flora [5]
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc61.07 yr (22,304 d)
|{{{apsis}}}|helion}}2.4621 AU
|{{{apsis}}}|helion}}2.0351 AU
2.2486 AU
Eccentricity0.0949
Orbital period3.37 yr (1,232 d)
Mean anomaly44.830°
Mean motion0° 17m 32.28s / day
Inclination6.8979°
Longitude of ascending node236.58°
317.02°
Physical characteristics
Mean diameter5.919±0.107 km[6]
6.032±0.082 km[7]
6.51 km (calculated)[5]
Rotation period11.946±0.006 h[8]
Geometric albedo0.24 (assumed)[5]
0.4044±0.0445[7]
0.419±0.085[6]
S (SDSS-MOC)[9]
S (Pan-STARRS)[5][10]
A (S3OS2-TH)[11]
A (S3OS2-BB)[11]
Absolute magnitude (H)12.7[7]
13.0[1][2]
13.1[5]
13.81±0.38[10]


2975 Spahr, provisional designation 1970 AF1, is a bright background asteroid from the Flora region of the inner asteroid belt, approximately 6 kilometers (3.7 miles) in diameter. It was discovered on 8 January 1970, by Russian astronomers Hejno Potter and A. Lokalov at the Cerro El Roble Station near Santiago, Chile.[1] The S- or A-type asteroid has a rotation period of 11.9 hours.[5] It was named for Timothy Spahr, an American astronomer and former director of the Minor Planet Center.[12]

Orbit and classification

Spahr is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.[3][4] Based on osculating Keplerian orbital elements, the asteroid has also been classified as a member of the Flora family (402), a giant asteroid family and the largest family of stony asteroids in the main-belt.[5]

It orbits the Sun in the inner asteroid belt at a distance of 2.0–2.5 AU once every 3 years and 4 months (1,232 days; semi-major axis of 2.25 AU). Its orbit has an eccentricity of 0.09 and an inclination of 7° with respect to the ecliptic.[2]

The asteroid was first observed as 1957 HU at the Johannesburg-Hartbeespoort Observatory (076) in April 1957. The body's observation arc begins as 1967 GH at Crimea-Nauchnij in April 1967, nearly 3 years prior to its official discovery observation at Cerro El Roble.[1]

Physical characteristics

In the SDSS-based taxonomy, Spahr is a stony S-type asteroid.[9] Pan-STARRS' survey also characterizes the body as an S-type,[5][10] while in both, the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), Spahr is an uncommon A-type asteroid.[4][11]

Rotation period

In December 2009, a first rotational lightcurve of Spahr was obtained from photometric observations by French amateur astronomer René Roy. Lightcurve analysis gave a rotation period of 11.946 hours with a relatively high brightness amplitude of 0.47 magnitude ({{{1}}}).[5][8]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Spahr measures between 5.919 and 6.032 kilometers in diameter and its surface has a high albedo between 0.4044 and 0.419.[6][7] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the parent body of the Flora family – and consequently calculates a larger diameter of 6.51 kilometers using an absolute magnitude of 13.1.[5]

Naming

This minor planet was named after Timothy Bruce Spahr (born 1970), a discoverer of minor planets and comets such as 171P/Spahr and 242P/Spahr, as well as a co-discoverer of Callirrhoe and Albiorix (moon), satellites of Jupiter and Saturn, respectively. Spahr was with the photographic Bigelow Sky Survey, which searched for high-latitude minor planets using the 0.41-m Catalina Schmidt telescope. (This survey was superseded by the Catalina Sky Survey). Spahr also headed the Minor Planet Center (MPC) from 2000 to 2014.[13] The asteroid's name was proposed by his MPC-colleges Brian Marsden, Gareth Williams and Stephen Larson,[12] and published by the MPC on 3 May 1996 (M.P.C. 27124).[14]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 "2975 Spahr (1970 AF1)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=2975. 
  2. ↑ 2.0 2.1 2.2 2.3 "JPL Small-Body Database Browser: 2975 Spahr (1970 AF1)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002975. 
  3. ↑ 3.0 3.1 "Asteroid (2975) Spahr". AstDyS-2, Asteroids – Dynamic Site. https://newton.spacedys.com/astdys/index.php?n=2975&pc=1.1.6. 
  4. ↑ 4.0 4.1 4.2 "Asteroid 2975 Spahr". Small Bodies Data Ferret. https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=2975+Spahr. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 "LCDB Data for (2975) Spahr". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=2975%7CSpahr. 
  6. ↑ 6.0 6.1 6.2 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J. et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal 741 (2): 20. doi:10.1088/0004-637X/741/2/68. Bibcode: 2011ApJ...741...68M. 
  7. ↑ 7.0 7.1 7.2 7.3 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. doi:10.1088/0004-637X/741/2/90. Bibcode: 2011ApJ...741...90M.  (catalog)
  8. ↑ 8.0 8.1 Behrend, Raoul. "Asteroids and comets rotation curves – (2975) Spahr". Geneva Observatory. http://obswww.unige.ch/~behrend/page4cou.html#002975. 
  9. ↑ 9.0 9.1 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. doi:10.1051/0004-6361/200913322. Bibcode: 2010A&A...510A..43C. https://sbnarchive.psi.edu/pds3/non_mission/EAR_A_I0035_5_SDSSTAX_V1_1/data/sdsstax_ast_table.tab. Retrieved 30 October 2019.  (PDS data set)
  10. ↑ 10.0 10.1 10.2 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. doi:10.1016/j.icarus.2015.08.007. Bibcode: 2015Icar..261...34V. 
  11. ↑ 11.0 11.1 11.2 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". Icarus 172 (1): 179–220. doi:10.1016/j.icarus.2004.06.006. Bibcode: 2004Icar..172..179L. http://sirrah.troja.mff.cuni.cz/yarko-site/tmp/eos/NEW/spectral_type_figure/s3os2.pdf. Retrieved 5 June 2018. 
  12. ↑ 12.0 12.1 Schmadel, Lutz D. (2007). "(2975) Spahr". Dictionary of Minor Planet Names – (2975) Spahr. Springer Berlin Heidelberg. p. 245. doi:10.1007/978-3-540-29925-7_2976. ISBN 978-3-540-00238-3. 
  13. ↑ "Tim Spahr of the Minor Planet Center – Planetary Radio". The Planetary Society. http://www.planetary.org/multimedia/planetary-radio/show/2013/20130708-tim-spahr-minor-planet-center.html. 
  14. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html. 

External links



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