_on_30_August_1979.webp) Coronagraph images of Comet Solwind 1 plunging towards the Sun on 30 August 1979 | |
| Discovery | |
|---|---|
| Discovered by | Solwind
|
| Discovery date | September 1981 |
| Designations | |
| Comet Howard–Koomen–Michels Solwind 1 1979 XI | |
| Orbital characteristics[1][2] | |
| Epoch | 30 August 1979 (JD 2444116.449) |
| Observation arc | 0.096 days (2.304 h) |
| Number of observations | 8 |
| Orbit type | Kreutz sungrazer |
| Perihelion | 0.0048 AU |
| Eccentricity | ~1.000 |
| Inclination | 141.456° |
| 344.997° | |
| Argument of periapsis | 67.688° |
| Last perihelion | 30 August 1979 |
| Physical characteristics[3] | |
| –4.0 (1979 apparition) | |
Comet Howard–Koomen–Michels, also formally known asC/1979 Q1 (Solwind),[1] was a largesungrazing comet that collided with theSun on August 30, 1979.[4] It is the first comet discovered by an orbiting satellite and the onlycomet known to have made contact with the Sun's surface, as most bodies vaporize before impact.[5]
_on_1979-08-30%2c_Cometography.jpg)
It was observed by the U.S.Naval Research Laboratory's white lightcoronagraph, aboard aUSAF satellite codenamedP78-1, also known asSolwind, on 30 August 1979.[4] 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 asVenus" in two photographs.[3] They initially mistook it as some large erroneous streak of light caused by the camera itself before realizing it was indeed a comet.[6] There were no confirmed ground observations of the comet at the time due to unfavorable weather conditions, though one possible coronagraph observations taken from theLomnický štít Observatory may have revealed dim features that may be caused by the disintegrated comet'stail moving a few hours after perihelion.[3]
Although the comet was never seen to reappear on the other side of the Sun, a notable brightening of thecorona was noticed, leading astronomers to presume that it either completely disintegrated shortly before perihelion or it collided directly to the Sun'sphotosphere.[3] This is the only known case of a comet that caused such brightening of the solar corona.[7]
The very few observations of the comet has made orbital calculations for it very problematic.[3] However,Brian G. Marsden was able to determine the comet as a member of theKreutz sungrazers, a family of sungrazing comets believed to be fragments of theGreat Comet of 1106.[7] After more comets were discovered by Solwind,SolarMax, and laterSOHO,[7] theIAU later changed theconvention for naming comets where a comet shall be named after asky survey orsatellite 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.[6]
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