4034 Vishnu (prov. designation: 1986 PA) is a rare-type asteroid classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 420 meters (1,400 feet) in diameter. It was discovered on 2 August 1986, by American astronomer Eleanor Helin at Palomar Observatory in California, United States. It is named after the Hindu deity Vishnu.[2]
| Discovery [1] | |
|---|---|
| Discovered by | E. F. Helin |
| Discovery site | Palomar Obs. |
| Discovery date | 2 August 1986 |
| Designations | |
MPC designation | (4034) Vishnu |
Named after | Vishnu (Hindu deity)[2] |
Alternative designations | 1986 PA |
Minor planet category | Apollo · NEO · PHA [1][2] |
| Orbital characteristics [1] | |
| Epoch 6 January 2010 (JD 2455202.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 28.93 yr (10,565 days) |
| Aphelion | 1.5299 AU |
| Perihelion | 0.5891 AU |
Semi-major axis | 1.0595 AU |
| Eccentricity | 0.4439 |
Orbital period (sidereal) | 1.09 yr (398 days) |
Mean anomaly | 62.851° |
Mean motion | 0° 54m 13.32s / day |
| Inclination | 11.170° |
Longitude of ascending node | 158.01° |
Argument of perihelion | 296.60° |
| Earth MOID | 0.0194 AU · 7.6 LD |
| Physical characteristics | |
Mean diameter | 0.42 km[3] |
Geometric albedo | 0.52[3] |
Spectral type | SMASS = O [1] |
Absolute magnitude (H) | 18.4[1] |
This minor planet was named for the four-armed god of protection and preservation of good, Vishnu, one of the principal deities of Hinduism. The asteroid's name was proposed by Belgian amateur astronomer and professional meteorologist Jean Meeus.[2][4] The approved naming citation was published by the Minor Planet Center on 15 July 2011 (M.P.C. 75547).[5]
Vishnu orbits the Sun at a distance of 0.6–1.5 AU once every 1 years and 1 month (398 days). Its orbit has an eccentricity of 0.44 and an inclination of 11° with respect to the ecliptic.[1] As no precoveries were taken, and no prior identifications were made, the body's observation arc begins with its official discovery observation at Palomar in 1986.[2]
Vishnu is a potentially hazardous asteroid due to its sufficiently large size and low Earth minimum orbital intersection distance of 0.0194 AU (2,900,000 km), which corresponds to 7.6 lunar distances.[1]
Its highly eccentric orbit crosses the orbits of all inner planets except that of Mercury, which effectively makes it a Venus-crosser, Earth-crosser and Mars-crosser all at once. From 1800 to 2200, Vishnu has made and will make multiple approaches of Venus (71×), Earth (29×), and Mars (7×) within 30 gigameters. It has been observed by radar astronomy (Binzel) and the orbital solution includes non-gravitational forces.[1]
In the SMASS taxonomy, Vishnu is a rare O-type asteroid, meaning it is similar to the asteroid 3628 Boznemcová, which is the best asteroid match to the spectra of L6 and LL6 ordinary chondrite meteorites. These L and LL chondrites have lower iron metal content, but higher iron oxide content in the silicates.[1]
In the early 2000s, Vishnu has been observed in the thermal-infrared by the Keck telescope on Mauna Kea, Hawaii. The asteroid measures approximately 420 meters in diameter and its surface has a high albedo of 0.520.[3] As of 2017, Vishnu's rotation period and shape remain unknown as no lightcurves have yet been obtained.[6]
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