C/1979 Q1 (Solwind)

C/1979 Q1 (Solwind)
Coronagraph images of Comet Solwind 1 plunging towards the Sun on 30 August 1979
Discovery
Discovered bySolwind
Russell A. Howard
Martin J. Koomen
Donald Michels
Discovery dateSeptember 1981
Designations
Comet Howard–Koomen–Michels
Solwind 1
1979 XI
Orbital characteristics[1][2]
Epoch30 August 1979 (JD 2444116.449)
Observation arc0.096 days (2.304 h)
Number of
observations		8
Orbit typeKreutz sungrazer
Perihelion0.0048 AU
Eccentricity~1.000
Inclination141.456°
344.997°
Argument of
periapsis		67.688°
Last perihelion30 August 1979
Physical characteristics[3]
–4.0
(1979 apparition)

Comet Howard–Koomen–Michels, also formally known as C/1979 Q1 (Solwind),[1] was a large sungrazing comet that collided with the Sun on August 30, 1979.[4] It is the first comet discovered by an orbiting satellite and the only comet known to have made contact with the Sun's surface, as most bodies vaporize before impact.[5]

Discovery and observations

Two images of C/1979 Q1 (Solwind) on 30 August 1979

It was observed by the U.S. Naval Research Laboratory's white light coronagraph, aboard a USAF satellite codenamed P78-1, also known as Solwind, 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 as Venus" 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 the Lomnický štít Observatory may have revealed dim features that may be caused by the disintegrated comet's tail 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 the corona was noticed, leading astronomers to presume that it either completely disintegrated shortly before perihelion or it collided directly to the Sun's photosphere.[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 the Kreutz sungrazers, a family of sungrazing comets believed to be fragments of the Great Comet of 1106.[7] After more comets were discovered by Solwind, SolarMax, and later SOHO,[7] the IAU later changed the convention for naming comets where a comet shall be named after a sky survey or satellite 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]

References

  1. ^ a b "C/1979 Q1 (Solwind)". www.minorplanetcenter.net. International Astronomical Union. Retrieved 16 December 2024.
  2. ^ "C/1979 Q1 (Solwind) – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 1 November 2024.
  3. ^ a b c d e A. Hale (29 August 2020). "Comet of the Week: Solwind 1 (1979 XI)". RocketSTEM.org. Retrieved 16 December 2024.
  4. ^ a b D. J. Michels; N. R. Sheeley, Jr.; R. A. Howard; M. J. Koomen (1982). "Observations of a Comet on Collision Course with the Sun". Science. 215 (4536): 1097–1102. doi:10.1126/SCIENCE.215.4536.1097. ISSN 0036-8075. PMID 17771842.
  5. ^ A. S. Ganesh (10 November 2021). "A Comet that Grazed the Sun". The Hindu. Retrieved 16 December 2024.
  6. ^ a b K. Battams (29 August 2014). "The Pivotal Discovery You've Probably Never Heard Of". planetarysociety.org. The Planetary Society. Retrieved 16 December 2024.
  7. ^ a b c G. W. Kronk. "C/1979 Q1 (Solwind 1)". Cometography.com. Retrieved 16 December 2024.