Comet Howard–Koomen–Michels, also formally known as C/1979 Q1 (Solwind), was a large sungrazing comet that collided with the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

on August 30, 1979. It is the first comet discovered by an orbiting satellite and the only

comet A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding ...

known to have made contact with the Sun's surface, as most bodies vaporize before impact.

Discovery and observations

It was observed by the U.S.

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's white light

coronagraph A coronagraph is a telescopic attachment designed to block out the direct light from a star or other bright object so that nearby objects – which otherwise would be hidden in the object's bright glare – can be resolved. Most coronagr ...

, aboard a

USAF The United States Air Force (USAF) is the Air force, air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its ori ...

satellite codenamed ''P78-1'', also known as

Solwind P78-1 or Solwind was a United States satellite launched aboard an Atlas F rocket from Vandenberg Air Force Base in California on February 24, 1979. The satellite's mission was extended by several weeks, so that it operated until it was destroye ...

, on 30 August 1979. However, it wasn't until September 1981 when a team of scientists, led by Russell Howard, Martin Koomen and Donald Michels reanalyzed Solwind data and found a "long-tailed comet as bright as

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

" in two photographs. They initially mistook it as some large erroneous streak of light caused by the camera itself before realizing it was indeed a comet. There were no confirmed ground observations of the comet at the time due to unfavorable weather conditions, though one possible coronagraph observations taken from the

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Observatory may have revealed dim features that may be caused by the disintegrated comet's

tail The tail is the elongated section at the rear end of a bilaterian animal's body; in general, the term refers to a distinct, flexible appendage extending backwards from the midline of the torso. In vertebrate animals that evolution, evolved to los ...

moving a few hours after perihelion. Although the comet was never seen to reappear on the other side of the Sun, a notable brightening of the

corona Corona (from the Latin for 'crown') most commonly refers to: * Stellar corona, the outer atmosphere of the Sun or another star * Corona (beer), a Mexican beer * Corona, informal term for the coronavirus or disease responsible for the COVID-19 ...

was noticed, leading astronomers to presume that it either completely disintegrated shortly before perihelion or it collided directly to the Sun's

photosphere The photosphere is a star's outer shell from which light is radiated. It extends into a star's surface until the plasma becomes opaque, equivalent to an optical depth of approximately , or equivalently, a depth from which 50% of light will esc ...

. This is the only known case of a comet that caused such brightening of the solar corona. The very few observations of the comet has made orbital calculations for it very problematic. However, Brian G. Marsden was able to determine the comet as a member of the

Kreutz sungrazers 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 ...

, a family of sungrazing comets believed to be fragments of the Great Comet of 1106. After more comets were discovered by Solwind, SolarMax, and later

SOHO SoHo, short for "South of Houston Street, Houston Street", is a neighborhood in Lower Manhattan, New York City. Since the 1970s, the neighborhood has been the location of many artists' lofts and art galleries, art installations such as The Wall ...

, the

IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

later changed the convention for naming comets where a comet shall be named after a

sky survey An astronomical survey is a general celestial cartography, map or astrophotography, image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of image ...

satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

used if the object itself were discovered by a large group of people, hence the comet being renamed from Howard–Koomen–Michels into Solwind 1.

References

External links

* {{DEFAULTSORT:Solwind, 1979 Q1 Kreutz Sungrazers Sungrazing comets Destroyed comets