C/2004 F4 (Bradfield)

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C/2004 F4 (Bradfield)
Bradfield.JPG
The comet in the dawn sky
Discovery [1]
Discovered by William A. Bradfield
Discovery date23 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 perihelion17 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]

Contents

Observational history

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 unsual, 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]

Related Research Articles

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<span class="mw-page-title-main">Comet Bennett</span> Icy small Solar System body; passed closest to Earth in 1970

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<span class="mw-page-title-main">Comet Pojmański</span>

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<span class="mw-page-title-main">Comet McNaught</span> Non-periodic comet

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<span class="mw-page-title-main">C/2002 T7 (LINEAR)</span>

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<span class="mw-page-title-main">C/2010 X1 (Elenin)</span> Oort cloud comet

Comet C/2010 X1 (Elenin) is an Oort cloud comet discovered by Russian amateur astronomer Leonid Elenin on December 10, 2010, through remote control of the International Scientific Optical Network's robotic observatory near Mayhill in the U.S. state of New Mexico. The discovery was made using the automated asteroids discovery program CoLiTec. At the time of discovery, the comet had an apparent magnitude of 19.5, which made it about 150,000 times fainter than can be seen with the naked eye. The discoverer, Leonid Elenin, originally estimated that the comet nucleus was 3–4 km in diameter, but more recent estimates place the pre-breakup size of the comet at 2 km. Comet Elenin started disintegrating in August 2011, and as of mid-October 2011 was not visible even using large ground-based telescopes.

<span class="mw-page-title-main">C/2011 W3 (Lovejoy)</span> Kreutz Sungrazer comet

Comet Lovejoy, formally designated C/2011 W3 (Lovejoy), is a long-period comet and Kreutz sungrazer. It was discovered in November 2011 by Australian amateur astronomer Terry Lovejoy. The comet's perihelion took it through the Sun's corona on 16 December 2011, after which it emerged intact, though greatly impacted by the event.

<span class="mw-page-title-main">C/2014 Q1 (PanSTARRS)</span>

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.

<span class="mw-page-title-main">252P/LINEAR</span> Periodic comet and near-earth object

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.

<span class="mw-page-title-main">NGC 7184</span> Galaxy in the constellation Aquarius

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.

<span class="mw-page-title-main">NGC 691</span> Galaxy in the constellation Aries

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.

<span class="mw-page-title-main">C/1979 Y1 (Bradfield)</span>

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.

<span class="mw-page-title-main">C/1941 B2 (de Kock–Paraskevopoulos)</span>

Comet de Kock–Paraskevopoulos is a non-periodic comet discovered on 15 January 1941. The comet reached an apparent magnitude of about +2.

C/1989 W1 (Aarseth–Brewington) is a non-periodic comet discovered on 16 November 1989 independently by Knut Aarseth and Howard Brewington. It reached an apparent magnitude of 2.8.

<span class="mw-page-title-main">C/2000 WM1 (LINEAR)</span>

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.

<span class="mw-page-title-main">C/2001 A2 (LINEAR)</span>

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.

References

  1. 1 2 3 "IAUC 8319: C/2004 F4". www.cbat.eps.harvard.edu. 12 April 2004. Retrieved 28 August 2023.
  2. 1 2 "Small-Body Database Lookup: C/2004 F4 (Bradfield)". ssd.jpl.nasa.gov.
  3. 1 2 "Brightest comets seen since 1935". www.icq.eps.harvard.edu. Retrieved 26 August 2023.
  4. ↑ "Pick of the Week: Comet Bradfield Coming into View (April 15, 2004)". soho.nascom.nasa.gov. Retrieved 28 August 2023.
  5. ↑ "SOHO-Gallery: Best Of SOHO". soho.nascom.nasa.gov. Retrieved 28 August 2023.
  6. 1 2 "IAUC 8326: C/2004 F4". www.cbat.eps.harvard.edu. 20 April 2004.
  7. ↑ "IAUC 8329: 2004bj, 2004bk; C/2002 T7; 1999 DJ_4; C/2004 F4". www.cbat.eps.harvard.edu. 23 April 2004.
  8. ↑ "IAUC 8334: 2004bl; C/2003 N2, O4-O8, P1,, P2; C/2004 F4". www.cbat.eps.harvard.edu. 30 April 2004.
  9. ↑ Pansecchi, L.; Scardia, M. (February 2005). "A neck-line structure in the dust tail of Comet C/2004 F4 (Bradfield)". Astronomy & Astrophysics. 430 (3): 1129–1132. doi:10.1051/0004-6361:20041766.
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