astro.wikisort.org - Asteroid

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]

2975 Spahr

Discovery [1]
Discovered by	H. Potter A. Lokalov
Discovery site	Cerro El Roble Stn.
Discovery date	8 January 1970
Designations
MPC designation	(2975) Spahr
Named after	Timothy Spahr [1] (MPC director)
Alternative designations	1970 AF1 · 1957 HU 1967 GH · 1970 AK1 1970 CB · 1978 PF4
Minor planet category	main-belt [1][2] · (inner) background [3][4] · Flora [5]
Orbital characteristics [2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	61.07 yr (22,304 d)
Aphelion	2.4621 AU
Perihelion	2.0351 AU
Semi-major axis	2.2486 AU
Eccentricity	0.0949
Orbital period (sidereal)	3.37 yr (1,232 d)
Mean anomaly	44.830°
Mean motion	0° 17m 32.28s / day
Inclination	6.8979°
Longitude of ascending node	236.58°
Argument of perihelion	317.02°
Physical characteristics
Mean diameter	5.919±0.107 km[6] 6.032±0.082 km[7] 6.51 km (calculated)[5]
Synodic rotation period	11.946±0.006 h[8]
Geometric albedo	0.24 (assumed)[5] 0.4044±0.0445[7] 0.419±0.085[6]
Spectral type	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]

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 (U=3-).[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

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 diagram · Orbital elements · Physical parameters

На других языках

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[de] (2975) Spahr

(2975) Spahr (1970 AF1; 1957 HU; 1967 GH; 1970 AK1; 1970 CB; 1978 PF4) ist ein ungefähr sechs Kilometer großer Asteroid des inneren Hauptgürtels, der am 8. Januar 1970 von den russischen (damals: Sowjetunion) Astronomen Heino Iogannowitsch Potter und A. Lokalow am Cerro El Roble-Observatorium auf dem Cerro El Roble im Nationalpark La Campana in der Región de Valparaíso in Chile (IAU-Code 805) entdeckt wurde.

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- [en] 2975 Spahr

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