Comet West

Last updated
C/1975 V1 (West)
C-west-1976-ps.jpg
Comet West on March 9, 1976
Discovery
Discovered by Richard M. West
Discovery dateAugust 10, 1975
Designations
C/1975 V1, 1976 VI, 1975n
Orbital characteristics
Epoch 1976-Mar-03
(JD 2442840.5) [1]
Aphelion 1,500 AU (inbound)
Perihelion 0.197 AU [1] [2]
Eccentricity 0.99997 [1] (near parabolic)
Orbital period chaotic (estimates up to 558,000 years)
Inclination 43.0664° [1]
Last perihelionFebruary 25, 1976 [1] [2]
Next perihelionunknown
Animation of C/1975 V1 orbit around Sun

.mw-parser-output .legend{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend-color{display:inline-block;min-width:1.25em;height:1.25em;line-height:1.25;margin:1px 0;text-align:center;border:1px solid black;background-color:transparent;color:black}.mw-parser-output .legend-text{}
C/1975 V1 *
Sun *
Mercury  *
Venus *
Earth  *
Mars Animation of C/1975 V1 orbit around Sun.gif
Animation of C/1975 V1 orbit around Sun
   C/1975 V1 ·  Sun ·  Mercury  ·  Venus ·  Earth ·  Mars

Comet West, formally designated C/1975 V1, 1976 VI, and 1975n, was a comet described as one of the brightest objects to pass through the inner Solar System in 1976. It is often described as a "great comet." [3]

Contents

History

It was discovered photographically by Richard M. West, of the European Southern Observatory, on August 10, 1975. The comet came to perihelion (closest approach to the Sun) on February 25, 1976. [1] During perihelion the comet had a minimum solar elongation of 6.4° and as a result of forward scattering reached a peak apparent magnitude of −3. [2] From February 2527, observers reported that the comet was bright enough to study during full daylight. [2]

Despite its brightness, Comet West went largely unreported in the popular media. This was partly due to the relatively disappointing display of Comet Kohoutek in 1973, which had been widely predicted to become extremely prominent: scientists were wary of making predictions that might raise public expectations. [4]

The New York Times , however, reported on March 2, 1976 that West was "a comet that may prove one of the brightest in this decade" and would be "visible to the unaided eye." [5]

Sky path for Comet West, with 7 day motion. The retrograde loops are caused by parallax from Earth's annual motion around the Sun. The most movement occurs when the comet is closest to Earth. Comet West skypath.png
Sky path for Comet West, with 7 day motion. The retrograde loops are caused by parallax from Earth's annual motion around the Sun. The most movement occurs when the comet is closest to Earth.

Period

With a nearly parabolic trajectory, estimates for the orbital period of this comet have varied from 254,000 [2] to 558,000 years. [6] Computing the best-fit orbit for this long-period comet is made more difficult since it underwent a splitting event which may have caused a non-gravitational perturbation of the orbit. The 2008 SAO Catalog of Cometary Orbits shows 195 observations for C/1975 V1 and 135 for C/1975 V1-A, for a combined total of 330 (218 observations were used in the fit).

Breakup

Before the perihelion passage, and using 28 positions obtained between 1975 August 10 and 1976 January 27, Comet West was estimated to have an orbital period of about 254,000 years. [2] As the comet passed within 30 million km of the Sun, the nucleus was observed to split into four fragments. [7]

The first report of the split came around 7 March 1976 12:30UT, when reports were received that the comet had broken into two pieces. Astronomer Steven O'Meara, using the 9-inch Harvard Refractor, reported that two additional fragments had formed on the morning of 18 March.[ citation needed ]

The fragmentation of the nucleus was, at the time, one of very few comet breakups observed, one of the most notable previous examples being the Great Comet of 1882, a member of the Kreutz Sungrazing 'family' of comets. More recently, comets Schwassmann-Wachmann-3 (73P), C/1999 S4 LINEAR, and 57P/du Toit-Neujmin-Delporte, have been observed to split or disintegrate during their passage close to the Sun.[ citation needed ]

The comet has been more than 50 AU (7.5 billion km) from the Sun since 2003. [8]

Nomenclature

In the nomenclature of the time, it was known as Comet 1976 VI or Comet 1975n, but the modern nomenclature is C/1975 V1. (Note that "1976 VI" uses the Roman numeral VI = 6, while "C/1975 V1" is the letter V and the number 1).

See also

Comet West in March 1976, around peak brightness. C-west-mar1976-ps.jpg
Comet West in March 1976, around peak brightness.

Related Research Articles

<span class="mw-page-title-main">Comet Hyakutake</span> Comet that passed close to Earth in 1996

Comet Hyakutake is a comet discovered on 31 January 1996. It was dubbed the Great Comet of 1996; its passage to within 0.1 AU (15 Gm) of the Earth on 25 March was one of the closest cometary approaches of the previous 200 years. Reaching an apparent visual magnitude of zero and spanning nearly 80°, Hyakutake appeared very bright in the night sky and was widely seen around the world. The comet temporarily upstaged the much anticipated Comet Hale–Bopp, which was approaching the inner Solar System at the time.

<span class="mw-page-title-main">Comet Ikeya–Seki</span> Long-period comet

Comet Ikeya–Seki, formally designated C/1965 S1, 1965 VIII, and 1965f, was a long-period comet discovered independently by Kaoru Ikeya and Tsutomu Seki. First observed as a faint telescopic object on September 18, 1965, the first calculations of its orbit suggested that on October 21, it would pass just 450,000 km (280,000 mi) above the Sun's surface, and would probably become extremely bright.

<span class="mw-page-title-main">Sungrazing comet</span> Comet that is extremely close to the sun during part of its orbit

A sungrazing comet is a comet that passes extremely close to the Sun at perihelion – sometimes within a few thousand kilometres of the Sun's surface. Although small sungrazers can completely evaporate during such a close approach to the Sun, larger sungrazers can survive many perihelion passages. However, the strong evaporation and tidal forces they experience often lead to their fragmentation.

<span class="mw-page-title-main">Great Comet of 1882</span> Astronomical object

The Great Comet of 1882 formally designated C/1882 R1, 1882 II, and 1882b, was a comet which became very bright in September 1882. It was a member of the Kreutz Sungrazers, a family of comets which pass within 1 R of the Sun's photosphere at perihelion. The comet was bright enough to be visible next to the Sun in the daytime sky at its perihelion. The comet made its closest approach to Earth on 16 September 1882 at 0.99 AU and then came to perihelion the next day on 17 September.

<span class="mw-page-title-main">Great January Comet of 1910</span> Comet

The Great January Comet of 1910, formally designated C/1910 A1 and often referred to as the Daylight Comet, was a comet which appeared in January 1910. It was already visible to the naked eye when it was first noticed, and many people independently "discovered" the comet. At its brightest, it outshone the planet Venus, and was possibly the brightest comet of the 20th century.

The Kreutz sungrazers are a family of sungrazing comets, characterized by orbits taking them extremely close to the Sun at perihelion. At the far extreme of their orbits, aphelion, Kreutz sungrazers can be a hundred times farther from the Sun than the Earth is, while their distance of closest approach can be less than twice the Sun's radius. They are believed to be fragments of one large comet that broke up several centuries ago and are named for German astronomer Heinrich Kreutz, who first demonstrated that they were related. These sungrazers make their way from the distant outer Solar System to the inner Solar System, to their perihelion point near the Sun, and then leave the inner Solar System in their return trip to their aphelion.

<span class="mw-page-title-main">Great Comet of 1680</span> First comet discovered by telescope

C/1680 V1, also called the Great Comet of 1680, Kirch's Comet, and Newton's Comet, was the first comet discovered by telescope. It was discovered by Gottfried Kirch and was one of the brightest comets of the seventeenth century.

Comet C/1861 G1 (Thatcher) is a long-period comet with roughly a 422-year orbit that is expected to return around 2283. It was discovered by A. E. Thatcher. It is responsible for the April Lyrid meteor shower. Carl Wilhelm Baeker also independently found this comet. The comet passed about 0.335 AU from the Earth on 5 May 1861 and last came to perihelion on 3 June 1861.

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

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.

<span class="mw-page-title-main">Great Comet of 1744</span> Non-periodic comet

The Great Comet of 1744, whose official designation is C/1743 X1, and which is also known as Comet de Chéseaux or Comet Klinkenberg-Chéseaux, was a spectacular comet that was observed during 1743 and 1744. It was discovered independently in late November 1743 by Jan de Munck, in the second week of December by Dirk Klinkenberg, and, four days later, by Jean-Philippe de Chéseaux. It became visible with the naked eye for several months in 1744 and displayed dramatic and unusual effects in the sky. Its absolute magnitude – or intrinsic brightness – of 0.5 was the sixth highest in recorded history. Its apparent magnitude may have reached as high as −7, leading it to be classified as a Great Comet. This comet is noted especially for developing a 'fan' of six tails after reaching its perihelion.

D/1770 L1, popularly known as Lexell's Comet after its orbit computer Anders Johan Lexell, was a comet discovered by astronomer Charles Messier in June 1770. It is notable for having passed closer to Earth than any other comet in recorded history, approaching to a distance of only 0.015 astronomical units, or six times the distance from the Earth to the Moon. The comet has not been seen since 1770 and is considered a lost comet.

<span class="mw-page-title-main">Great Southern Comet of 1887</span> Kreutz comet

The Great Southern Comet of 1887, or C/1887 B1 using its International Astronomical Union (IAU) designation, was a bright comet seen from the Southern Hemisphere during January 1887. Later calculations indicated it to be part of the Kreutz Sungrazing group. It came to perihelion on 11 January 1877 at a distance of 0.00483 AU (723 thousand km) with a velocity of 606.1 km/s. Since the Sun has a radius of 696000 km, the comet passed about 27000 km from the surface of the Sun.

<span class="mw-page-title-main">Great Comet of 1901</span> Comet

The Great Comet of 1901, sometimes known as Comet Viscara, formally designated C/1901 G1, was a comet which became bright in the spring of 1901. Visible exclusively from the southern hemisphere, it was discovered on the morning of April 12, 1901 as a naked-eye object of second magnitude with a short tail. On the day of perihelion passage, the comet's head was reported as deep yellowish in color, trailing a 10-degree tail. It was last seen by the naked eye on May 23.

<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.

C/1865 B1 was a non-periodic comet, which in 1865 was so bright that it was visible to unaided-eye observations in the Southern Hemisphere. The comet could not be seen from the Northern Hemisphere.

<span class="mw-page-title-main">C/2019 Y4 (ATLAS)</span> Non-periodic comet

C/2019 Y4 (ATLAS) was a comet with a near-parabolic orbit discovered by the ATLAS survey on December 28, 2019. Early predictions based on the brightening rate suggested that the comet could become as bright as magnitude 0 matching the brightness of Vega. It received widespread media coverage due to its dramatic increase in brightness and orbit similar to the Great Comet of 1844, but on March 22, 2020, the comet started disintegrating. Such fragmentation events are very common for Kreutz Sungrazers. The comet continues to fade and did not reach naked eye visibility. By mid-May, comet ATLAS appeared very diffuse even in a telescope. C/2019 Y4 (ATLAS) has not been seen since May 21, 2020.

<span class="mw-page-title-main">Comet NEOWISE</span> Bright comet of July 2020

C/2020 F3 (NEOWISE) or Comet NEOWISE is a long period comet with a near-parabolic orbit discovered on March 27, 2020, by astronomers during the NEOWISE mission of the Wide-field Infrared Survey Explorer (WISE) space telescope. At that time, it was an 18th-magnitude object, located 2 AU away from the Sun and 1.7 AU away from Earth.

<span class="mw-page-title-main">C/2021 A1 (Leonard)</span> Hyperbolic comet

C/2021 A1 (Leonard) was a long period comet that was discovered by G. J. Leonard at the Mount Lemmon Observatory on 3 January 2021 when the comet was 5 AU (750 million km) from the Sun. It had a retrograde orbit. The nucleus was about 1 km across. It came within 4 million km (2.5 million mi) of Venus, the closest-known cometary approach to Venus.

C/2021 O3 (PanSTARRS) is perhaps an Oort cloud comet, discovered on 26 July 2021 by the Pan-STARRS sky survey. It came to perihelion on 21 April 2022 at 0.287 AU (42.9 million km). from the Sun.

<span class="mw-page-title-main">Comet Kohoutek</span> Hyperbolic comet

Comet Kohoutek is a comet that passed close to the Sun towards the end of 1973. Early predictions of the comet's peak brightness suggested that it had the potential to become one of the brightest comets of the 20th century, capturing the attention of the wider public and the press and earning the comet the moniker of "Comet of the Century". Although Kohoutek became rather bright, the comet was ultimately far dimmer than the optimistic projections: its apparent magnitude peaked at only –3 and it was visible for only a short period, quickly dimming below naked-eye visibility by the end of January 1974.

References

  1. 1 2 3 4 5 6 "JPL Small-Body Database Browser: C/1975 V1-A (West)" (1976-09-25 last obs (arc=412 days)). Jet Propulsion Laboratory . Retrieved 2011-08-07.
  2. 1 2 3 4 5 6 Gary W. Kronk. "C/1975 V1 (West)". Cometography. Retrieved 2011-02-01.
  3. Donald K. Yeomans (April 2007). "Great Comets in History". Jet Propulsion Laboratory/California Institute of Technology (Solar System Dynamics). Retrieved 2007-12-28.
  4. Burnham, R. and Levy, D. Great Comets, Cambridge: Cambridge University Press, 2000, p. 73
  5. Sullivan, Walter (March 2, 1976). "Comet Expected in Sky for Week". nytimes.com. New York City: New York Times. p. 17. Retrieved November 16, 2023. From tomorrow until Sunday a comet that may prove one of the brightest in this decade is expected to reach maximum visibility in the eastern sky before sunrise. ... By Wednesday, Dr. Marsden believes, it will be far enough from the sun to be visible to the unaided eye.
  6. Jerry Coffey (2009-09-21). "Comet West". Universe Today. Archived from the original on 2012-09-20. Retrieved 2011-02-01.
  7. COMETS!: Visitors from Deep Space pg77
  8. Horizons output. "Observer Table for Comet C/1975 V1-A (West)" . Retrieved 2019-02-25. (Observer Location:@sun)