_on_Jul_14_2020_aligned_to_stars.jpg) Comet NEOWISE photographed from Germany on July 14, 2020 | |
| Discovery[1] | |
|---|---|
| Discovered by | NEOWISE |
| Discovery date | March 27, 2020 |
| Designations | |
| CK20F030 | |
| Orbital characteristics[2][3] | |
| Epoch | July 6, 2020 (JD 2459036.5) |
| Observation arc | 1.2 years (438 days) |
| Number of observations | 1,315 |
| Aphelion | 538 AU (inbound) 710 AU (outbound) |
| Perihelion | 0.295 AU |
| Semi-major axis | 270 AU (inbound) 355 AU (outbound) |
| Eccentricity | 0.99921 |
| Orbital period | ~4,500 yrs (inbound) ~6,800 yrs (outbound) |
| Inclination | 128.94° |
| 61.010° | |
| Argument of periapsis | 37.279° |
| Mean anomaly | 0.0003° |
| Last perihelion | 3 July 2020 |
| TJupiter | −0.408 |
| EarthMOID | 0.362 AU |
| JupiterMOID | 0.813 AU |
| Physical characteristics[1] | |
| Dimensions | ~5.0 km (3.1 mi) |
| 7.58±0.03 hours | |
| Comet total magnitude (M1) | 7.5–12.1 |
| 0.5–1.0 (2020 apparition) | |
C/2020 F3 (NEOWISE) orComet NEOWISE is along period comet with anear-parabolic orbit discovered on March 27, 2020, by astronomers during theNEOWISE mission of theWide-field Infrared Survey Explorer (WISE)space telescope. At that time, it was an18th-magnitude object, located 2.0 AU (300 million km; 190 million mi) away from the Sun and 1.7 AU (250 million km; 160 million mi) away from Earth.[4]
NEOWISE is known for being the brightest comet in the northern hemisphere sinceComet Hale–Bopp in 1997.[5] It was widely photographed by professional and amateur observers and was even spotted by people living near city centers and areas withlight pollution.[6] While it was too close to the Sun to be observed atperihelion, it emerged from perihelion around magnitude 0.5 to 1, making it bright enough to be visible to thenaked eye.[7] Under dark skies, it could be seen with the naked eye and remained visible to the naked eye throughout July 2020.[8][9] By July 30, the comet was aboutmagnitude 5,[10] when binoculars were required nearurban areas to locate the comet.
For observers in theNorthern Hemisphere, the comet could be seen on the northwestern horizon, below theBig Dipper. North of 45 degrees north, the comet was visible all night in mid-July 2020. On July 30, Comet NEOWISE entered theconstellation ofComa Berenices, below the bright starArcturus.
NEOWISE was retroactively dubbed theGreat Comet of 2020.
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The object was discovered by a team using theWISE space telescope under the NEOWISE program on March 27, 2020.[1] It was classified as acomet on March 31 and named after NEOWISE on April 1.[4] It has thesystematic designationC/2020 F3, indicating a non-periodic comet which was the third discovered in thesecond half of March 2020.
Comet NEOWISE made its closest approach to the Sun (perihelion) on July 3, 2020, at a distance of 0.29 AU (43 million km; 27 million mi). This passage through the planetary region increases the comet'sorbital period from about 4500 years to about 6800 years.[2] Its closest approach to Earth occurred on July 23, 2020, 01:09 UTC, at a distance of 0.69 AU (103 million km; 64 million mi) while located in the constellation ofUrsa Major.[11]
In early July, the comet could be seen in the morning sky just above the north-eastern horizon and belowCapella. Seen from Earth, the comet was less than 20 degrees from the Sun between June 11–July 9, 2020. By June 10, 2020 as the comet was being lost to the glare of the Sun, it wasapparent magnitude 7.0,[10] when it was 0.7 AU (100 million km; 65 million mi) away from Sun and 1.6 AU (240 million km; 150 million mi) away from Earth. When the comet entered the field of view of theSOHO spacecraft'sLASCO C3 instrument on June 22, 2020, the comet had brightened to about magnitude 3.0, when it was 0.4 AU (60 million km; 37 million mi) away from the Sun and 1.4 AU (210 million km; 130 million mi) away from Earth.[10]
By early July, Comet NEOWISE had brightened to magnitude 1.0,[12][13] far exceeding the brightness attained by previous comets that year,C/2020 F8 (SWAN), andC/2019 Y4 (ATLAS). By July, it also had developed a second tail. The first tail was blue and made ofgas and ions. There was also a red separation in the tail caused by high amounts of sodium. The second twin tail was a golden color and was made ofdust, like the tail ofComet Hale–Bopp.[citation needed] The comet was brighter thanC/2011 L4 (PanSTARRS),[14] but not as bright as Hale–Bopp was in 1997. After perihelion, the comet began to fade, dropping to magnitude 2.0 in mid-July.[15] Its nucleus activity subdued after mid-July, and its green coma was clearly visible after that.
On July 13, 2020, a sodium tail was confirmed by the Planetary Science Institute's Input/Output facility.[16] Sodium tails have only been observed in very bright comets such as Hale–Bopp andC/2012 S1 (ISON).
From theinfrared signature, the diameter of thecomet nucleus is estimated to be approximately 5 km (3.1 mi).[1] The nucleus is similar in size toComet Hyakutake and manyshort-period comets such as2P/Encke,7P/Pons–Winnecke,8P/Tuttle,14P/Wolf, and19P/Borrelly.[17] By July 5, NASA'sParker Solar Probe had captured an image of the comet, from which astronomers also estimated the diameter of the comet nucleus at approximately 5 km (3.1 mi) as well.[18]Later in July 2020, other observations were also reported, including those related to coma morphology,[19] and spectrographic emissions.[20][21][22][23] On 31 July 2020, strong detection of OH 18-cm emission was observed in radio spectroscopic studies at theArecibo Observatory.[24]On August 14, 2020, the rotation period of the comet was reported to be "7.58±0.03 hr".[25]
After its perihelion and closest approach to Earth, a number of authors have suggested considering NEOWISE as agreat comet.[26][27][28][29][30][31] Others have argued that it lacked the brightness and visible tail to qualify.[32] Retroactively, in the years that followed, NEOWISE is commonly remembered as a great comet.[33][34]
![[icon]](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aWiki_letter_w_cropped.svg) | This sectionneeds expansion. You can help byadding to it.(July 2020) |
Comet NEOWISE's retrograde orbit crossed to the north of the plane of the ecliptic, to which it is inclined at approximately 129 degrees, on June 29, 2020, 01:47 UTC.[12][2] It made its closest approach to the Sun (perihelion) on July 3, 2020, at a distance of 0.29 AU (43 million km; 27 million mi). This passage increases the comet'sorbital period from about 4400 years to about 6700 years.[2] On July 18, the comet peaked at a northerndeclination of +48 and was circumpolar down to latitude 42N.[11] Its closest approach to Earth occurred on July 23, 2020, 01:09 UTC, at a distance of 0.69 AU (103 million km; 64 million mi) while located in the constellation ofUrsa Major.[11]
The fictional comet Dibiasky on the 2021 filmDon't Look Up was "very loosely" modelled after comet NEOWISE.[35][36]
In chronological order:
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2020 in space | ||
|---|---|---|
| Space probe launches  |
|   |
| Impact events | ||
| Selected NEOs | ||
| Exoplanets |
| |
| Discoveries |
| |
| Comets | ||
| Space exploration |
| |
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