2975 Spahr
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| Discovery[1] | |
|---|---|
| Discovered by | H. Potter A. Lokalov |
| Discovery site | Cerro El Roble Stn. |
| Discovery date | 8 January 1970 |
| Designations | |
| (2975) Spahr | |
Named after | Timothy Spahr[1] (MPC director) |
| 1970 AF1 · 1957 HU 1967 GH · 1970 AK1 1970 CB · 1978 PF4 | |
| 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 |
| 2.2486 AU | |
| Eccentricity | 0.0949 |
| 3.37 yr (1,232 d) | |
| 44.830° | |
| 0° 17m 32.28s / day | |
| Inclination | 6.8979° |
| 236.58° | |
| 317.02° | |
| Physical characteristics | |
| 5.919±0.107 km[6] 6.032±0.082 km[7] 6.51 km (calculated)[5] | |
| 11.946±0.006 h[8] | |
| 0.24 (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] | |
| 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]
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]
