(5587) 1990 SB

History

was discovered on 16 September 1990 by astronomers Henry E. Holt and J. A. Brown, who noted its fast motion at that time. It was observed using the 48-in Schmidt telescope at Palomar Observatory. It was given the provisional designation , and its discovery was announced in an International Astronomical Union Circular on 22 September. The asteroid was observed by the Crimean Astrophysical Observatory on 23 October, but it was reported as a new asteroid and given the provisional designation . The 23 October observation was later linked to by the Minor Planet Center on 4 June 1993, and the asteroid received the number (5587) that same day. , it remains unnamed.

Orbit

is classified as a near-Earth object (NEO) of the Amor class. The Amor asteroids are a group of NEOs that have semi-major axes greater than one astronomical unit (AU) and do not cross Earth's orbit. has a semi-major axis of 2.40 AU, taking 3.72 years to complete one orbit around the Sun. Along its orbit, its distance from the Sun varies from 1.09 AU at perihelion to 3.71 AU at aphelion, due to its orbital eccentricity of 0.54. Its orbit is inclined by 18° with respect to the ecliptic plane.

Physical characteristics

is about 3.57 km in size, based on thermal models using thermal-infrared observations from the Keck telescope. Photometric observations suggest that its shape is quite elongated, with axes ratios of a/b = 2.0 and b/c = 1.2. Its shape is also regular and symmetrical. Any concavities are not very deep; if it is a contact binary object, it is not very strongly bifurcated. The asteroid is classified as an Sq-type asteroid under the Bus classification scheme. In 2003, a team of astronomers led by C. L. Dandy suggested that it is instead intermediate between the Q-type and R-type. However, a 2007 study reaffirmed that 's spectrum is consistent with an Sq-type classification.

Observations of 's lightcurve, or variations in its observed brightness, indicate that it has a rotation period of 5.05 hours. Its spin pole points toward the ecliptic south, meaning that the asteroid rotates in a retrograde direction.

References

References

1. "NEO Groups". NASA/JPL Near-Earth Object Program Office.