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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. The S- or A-type asteroid has a rotation period of 11.9 hours. It was named for Timothy Spahr, an American astronomer and former director of the Minor Planet Center.

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. 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.

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.

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.

Physical characteristics

In the SDSS-based taxonomy, Spahr is a stony S-type asteroid. Pan-STARRS' survey also characterizes the body as an S-type, 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.

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 (U=3-).

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. 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.

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. The asteroid's name was proposed by his MPC-colleges Brian Marsden, Gareth Williams and Stephen Larson, and published by the MPC on 3 May 1996 (M.P.C. 27124).

References

1. ^ "2975 Spahr (1970 AF1)". Minor Planet Center. Retrieved 5 June 2018.
2. ^ "JPL Small-Body Database Browser: 2975 Spahr (1970 AF1)" (2018-05-24 last obs.). Jet Propulsion Laboratory. Retrieved 5 June 2018.
3. ^ "Asteroid (2975) Spahr". AstDyS-2, Asteroids – Dynamic Site. Retrieved 5 June 2018.
4. ^ "Asteroid 2975 Spahr". Small Bodies Data Ferret. Retrieved 5 June 2018.
5. ^ "LCDB Data for (2975) Spahr". Asteroid Lightcurve Database (LCDB). Retrieved 5 June 2018.
6. ^ 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. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. S2CID 118745497.
7. ^ 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. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. S2CID 35447010. (catalog)
8. ^ Behrend, Raoul. "Asteroids and comets rotation curves – (2975) Spahr". Geneva Observatory. Retrieved 5 June 2018.
9. ^ 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 30 October 2019. (PDS data set)
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. S2CID 53493339.
11. ^ 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 5 June 2018.
12. ^ 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. Retrieved 5 June 2018.
14. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 5 June 2018.

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 2975 Spahr at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 2975 Spahr at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Background asteroids
• Named minor planets
• Astronomical objects discovered in 1970