 Infrared image of C/2016 U1 (NEOWISE) taken on 21 November 2016 | |
| Discovery[1] | |
|---|---|
| Discovered by | NEOWISE |
| Discovery date | 21 October 2016 |
| Orbital characteristics[2] | |
| Epoch | 12 December 2016 (JD 2457734.5) |
| Observation arc | 83 days |
| Number of observations | 366 |
| Perihelion | 0.319 AU |
| Eccentricity | 1.00025 |
| Inclination | 46.435° |
| 61.429° | |
| Argument of periapsis | 162.75° |
| Mean anomaly | –0.001° |
| Last perihelion | 14 January 2017 |
| TJupiter | 0.489 |
| EarthMOID | 0.589 AU |
| JupiterMOID | 0.811 AU |
| Physical characteristics | |
| Comet total magnitude (M1) | 13.1 |
| Comet nuclear magnitude (M2) | 19.5 |
| 6.8 (2017 apparition)[3] | |
C/2016 U1 (NEOWISE) is anon-periodic comet discovered on 21 October 2016 byNEOWISE, the asteroid-and-comet-hunting portion of theWide-field Infrared Survey Explorer (WISE) mission.[4][5] The comet brightened to magnitude +6.8[6] and could be observed with binoculars,[7] during the first week of 2017 and it was closest to theSun on 14 January 2017.[4][8]
It was closest to the Earth on 13 December 2016 at a distance of 0.709 AU (106.1 million km) away,[7] and it is not considered a threat to Earth.[4] The aphelion of the comet lies at the inner edge of theOort cloud and it is possible that the 2017 perihelion was not the first and that during a previous perihelion planetary perturbations pushed the comet towards the Oort cloud. Despite its small size, the comet survived perihelion and was observed for days from the SWAN instrument on boardSOHO.[9]
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