Discovery [1] | |
---|---|
Discovered by | William A. Bradfield |
Discovery date | 23 March 2004 |
Orbital characteristics [2] | |
Epoch | 2004-Jun-01.0 |
Observation arc | 155 days |
Aphelion | 475 AU |
Perihelion | 0.168 AU |
Semi-major axis | 238 AU |
Eccentricity | 0.99929 |
Orbital period | 3,660 years |
Inclination | 63.16° |
222.78° | |
Argument of periapsis | 332.79° |
Last perihelion | 17 April 2004 |
Earth MOID | 0.32 AU |
Jupiter MOID | 0.56 AU |
Comet total magnitude (M1) | 11.3 |
C/2004 F4 (Bradfield) is a non-periodic comet discovered by amateur astronomer William A. Bradfield on 23 March 2004. [1] The comet brightened to an apparent magnitude of about 3.3. [3]
The comet was discovered by amateur astronomer William A. Bradfield from Yankalilla, South Australia on 23 March 2004 with a 0.25-m reflector telescope, during his search for sungrazing comets. That was Bradfield's 18th comet discovery. The comet was then located in evening twilight and its magnitude was estimated to be about magnitude 8. Robert H. McNaught observed the comet on 9 April 2004 and estimated that the comet had a magnitude of 5, while Terry Lovejoy estimated its magnitude to be 3.3 on 12 April, while its tail measured half a degree long. [1] At that time, two more naked eye comets were visible in the sky, C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR). [3]
The comet reached perihelion on 17 April 2004, at a distance of 0.168 AU (25.1 million km; 15.6 million mi). [2] The comet became visible in the C3 coronograph of the Solar and Heliospheric Observatory (SOHO) between 16 and 20 April 2004. [4] The comet had a bright head and a long white tail. [5] The appearance of the comet was in the coronograph was unusual, with the coma growing perpendicularly to the apparent motion, and thus indicating a growing dust tail, while on 19 April a series of structures were seen near the head, probably streamers or striae. If these were streamers, they indicated an uprise in activity every 0.5 day. [6] The orbital ephimeris based on the SOHO observations indicated that the comet on 20 April had an magnitude of 2.5. [6]
The comet was spotted in bright twilight on 22 April, when the comet had an estimated magnitude of about 4 to 4.5. [7] On 25 April, while the comet was estimated to have a same magnitude, its tail was estimated to 8.5 degrees long with naked eye, while on 27 April the tail length was estimated to be 10 degrees with 7×35 binoculars, while the comet was estimated to have a magnitude of 5. On 30 April the apparent magnitude was estimated to be 5.8 while the tail was estimated to be 3.5 degrees long. [8]
On 2–3 May, Earth crossed the orbital plane of the comet. As a result, a sunward spike (or anti-tail) and a ray-shaped structure in the dust tail. [9]
65P/Gunn is a periodic comet in the Solar System which has a current orbital period of 6.79 years. The comet is a short-period comet, orbiting the Sun every 6.79 years inside the main asteroid belt between the orbits of the planets Mars and Jupiter.
121P/Shoemaker–Holt, also known as Shoemaker-Holt 2, is a periodic comet in the Solar System with an orbital period of about 8 years. The comet was discovered by Carolyn S. Shoemaker, Eugene M. Shoemaker, and Henry E. Holt on 9 March 1989. The comet then had an apparent magnitude of 13, was diffuse and had a tail about 2 arcminutes long. It was recovered by James V. Scotti on 29 August 1995 in images obtained as part of the Spacewatch survey.
173P/Mueller, also known as Mueller 5, is a periodic comet in the Solar System with an orbital period of 13.6 years.
Comet McNaught, also known as the Great Comet of 2007 and given the designation C/2006 P1, is a non-periodic comet discovered on 7 August 2006 by British-Australian astronomer Robert H. McNaught using the Uppsala Southern Schmidt Telescope. It was the brightest comet in over 40 years, and was easily visible to the naked eye for observers in the Southern Hemisphere in January and February 2007.
Comet Lulin, formal designation C/2007 N3, Traditional Chinese:鹿林彗星) is a non-periodic comet. It was discovered by Ye Quanzhi and Lin Chi-Sheng from Lulin Observatory. It peaked in brightness at magnitude between +4.5 and +5, becoming visible to the naked eye, and arrived at perigee for observers on Earth on February 24, 2009, and at 0.411 AU from Earth.
C/2002 T7 (LINEAR) is a non-periodic comet discovered in 2002 by LINEAR project. The comet brightened to a magnitude of 2.2.
122P/de Vico is a periodic comet with an orbital period of 74 years. It fits the classical definition of a Halley-type comet with. It was discovered by Francesco de Vico in Rome on February 20, 1846.
125P/Spacewatch is a periodic Jupiter-family comet. It was discovered on September 8, 1991, by Tom Gehrels using the 0.91 m Spacewatch telescope at the Kitt Peak National Observatory. It was the first comet discovered with the use of a CCD and also the faintest comet upon discovery up to that point. It has a diameter of 1.6 km.
C/2014 Q1 (PanSTARRS) is a non-periodic/long period comet discovered on 16 August 2014 by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS). The comet after its perihelion on July 6, 2015 reached a magnitude of +4 while being in evening twilight. The comet after perihelion featured three tails.
Comet 252P/LINEAR is a periodic comet and near-Earth object discovered by the LINEAR survey on April 7, 2000. The comet is a Jupiter family comet, meaning that it passes quite close to the orbit of Jupiter.
126P/IRAS is a periodic comet with an orbital period of 13.4 years. It was discovered in images taken by the Infrared Astronomical Satellite (IRAS) on 28 July 1983 by J. Davies. The discovery was confirmed with images taken with the 1.2-m Schmidt telescope at Palomar Observatory.
Comet 141P/Machholz or 141P/Machholz 2 is a periodic Jupiter family comet with an orbital period of 5.3 years. It was discovered by Donald Machholz on 13 August 1994. A few days after the discovery a number of condensations were found near the main component of the comet, indicating that the comet had fragmented between 1987 and 1989, during its previous perihelion.
185P/Petriew is a periodic comet with an orbital period of 5.5 years. It was discovered by amateur astronomer Vance Avery Petriew on 18 August 2001.
207P/NEAT is a periodic Jupiter-family comet with an orbital period of 7.62 years. It was discovered by Near Earth Asteroid Tracking (NEAT) on 11 March 2001.
210P/Christensen is a Jupiter family periodic comet with an orbital period of 5.7 years. It was discovered by Eric J. Christensen on 26 May 2003 in images taken by the Catalina Sky Survey and recovered in images obtained by STEREO, the first time a single-apparition comet was recovered by a spacecraft.
NGC 7184 is a barred spiral galaxy located in the constellation Aquarius. It is located at a distance of circa 100 million light years from Earth, which, given its apparent dimensions, means that NGC 7184 is about 175,000 light years across. It was discovered by William Herschel on October 28, 1783.
NGC 691 is an unbarred spiral galaxy located in the constellation Aries. It is located at a distance of circa 120 million light years from Earth, which, given its apparent dimensions, means that NGC 691 is about 130,000 light years across. It was discovered by William Herschel on November 13, 1786.
C/1979 Y1 (Bradfield), also known as Comet 1979X and 1979l, is a long period comet discovered by William A. Bradfield on 24 December 1979. The comet has an orbital period of 308 ± 6 years and last passed perihelion on 21 December 1979. It is considered to be the parent body of the July Pegasids meteor shower. It is expected to next come to perihelion around 2287.
C/2000 WM1 (LINEAR) is a non-periodic comet discovered by LINEAR on 16 December 2000. The comet brightened to an apparent magnitude of about 2.5.
C/2001 A2 (LINEAR) is a non-periodic comet from the Oort cloud discovered by LINEAR on 15 January 2001. The nucleus of comet split in multible fragments during its perihelion passage. The comet brightened to an apparent magnitude of about 3.