sungrazing

Sungrazing refers to the trajectory of a celestial object that passes extremely close to the Sun. In practice, the term is most often applied to comets, though asteroids and dust particles can also have sungrazing paths. Sungrazers are defined by perihelion distances of only a few solar radii, bringing them into intense solar radiation, tidal, and particle environments.

The majority of known sungrazers belong to specific orbital families, most notably the Kreutz sungrazers, which share a common long-term orbital path and are believed to be fragments of a single progenitor that broke apart centuries ago. Other recognized groups include the Marsden and Kracht families, identified by astronomers from recurring, tightly clustered orbits that bring them very close to the Sun.

Sungrazers are frequently discovered by space-based solar observatories such as the Solar and Heliospheric Observatory (SOHO) and the STEREO spacecraft, which monitor the Sun's corona. The extreme heat and tidal forces near perihelion often cause these comets to shed large portions of their material or completely disintegrate, although a few may survive perihelion and be visible from Earth as they move away from the Sun.

Examples include Comet Lovejoy (C/2011 W3), which survived perihelion in 2011 and was observed from Earth afterward, while Comet ISON (C/2012 S1) disintegrated near its perihelion in 2013. Kreutz sungrazers have produced many spectacular but short-lived appearances since the late 20th century.

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