Near-Earth asteroid
1685 Toro (prov. designation 1948 OA ) is anasteroid andnear-Earth object of theApollo group on an eccentric orbit. It was discovered on 17 July 1948, by American astronomerCarl Wirtanen atLick Observatory on Mount Hamilton, California.[ 3] [ 20] S-type asteroid has arotation period of 10.2 hours and measures approximately 4 kilometers (2.5 miles) in diameter. It is named for Betulia Toro Herrick, wife of astronomerSamuel Herrick .[ 2]
Classification and orbit [ edit ] Toro is anApollo asteroid , a subgroup of near-Earth asteroids thatcross the orbit of Earth . It orbits the Sun at a distance of 0.8–2.0 AU once every 584 days. Its orbit has aneccentricity of 0.44 and aninclination of 9° with respect to theecliptic .[ 1]
This asteroid's orbit also shows a5:8 resonance with Earth[ 21] Venus . This near resonance results from Earth and Venus being in a near 8:13 resonance with each other. It was the third Apollo asteroid to be discovered. The current resonance with Earth will last for only a few thousand years. Calculations show that Toro will leave it in 2960 CE , and that it will enter the region of 5:13 resonance with Venus in 3470 CE . This is because the distance from Earth's orbit will become larger and that from Venus's orbit smaller. A study of long-term stability shows that the alternating resonances will possibly be broken roughly 3 million years from now because of close approaches between Toro andMars .[ 22] [better source needed
Toro' s Earthminimum orbit intersection distance of 0.051 AU (7,630,000 km),[ 1] potentially hazardous asteroid . With anorbital uncertainty U = 0, its orbit and future close approaches are well determined.[ 1]
Toro's orbit may be similar to that of theSylacauga meteorite , the first meteorite authenticated to have struck a human.[ 23]
Thisminor planet was named after the maiden name of Betulia (née Toro) Herrick, wife of American astronomerSamuel Herrick . Herrick had studied the asteroid's orbit, and requested the name, along with the other asteroid,1580 Betulia .[ 24] [ 25] naming citation was published by theMinor Planet Center on 10 March 1966 (M.P.C. 2504[ 26]
Physical characteristics [ edit ] In theTholen andSMASS taxonomic scheme, Toro is characterized as a stonyS-type asteroid .[ 1] L chondrite [ 27] albedo in the range of 0.24–0.34. It has an extremely well-measuredrotation period of 10.2 hours.[ 7] [ 8] [ 10] [ 11] [ 12] [ 13] [ 14] [ 6] YORP effect .[ 6]
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