Cygnus Loop

An emission nebula in the constellation Cygnus. The Veil nebula (NGC 6960, 6990, 6995) forms part of the Cygnus Loop. It is the supernova remnant of a star that exploded probably some 50 000 years ago. The remnant now has an area of about 3 square degrees and is about 800 parsecs away. Its rate of expansion has gradually slowed to its present 100 km s^–1 as the expanding shell collides with and sweeps up any surrounding interstellar matter. This creates a shock wave that compresses, heats, and ionizes the gas atoms, which then become visible as the emission nebula.

Cygnus loop

[′sig·nəs ‚lüp] (astronomy) A supernova remnant about 17,000 years old, and 30-40 parsecs across and probably about 770 parsecs distant that emits radio waves and x-rays as well as visible light. Also known as Veil Nebula.

单词	cygnus loop
释义	Cygnus Loop Cygnus Loop An emission nebula in the constellation Cygnus. The Veil nebula (NGC 6960, 6990, 6995) forms part of the Cygnus Loop. It is the supernova remnant of a star that exploded probably some 50 000 years ago. The remnant now has an area of about 3 square degrees and is about 800 parsecs away. Its rate of expansion has gradually slowed to its present 100 km s^–1 as the expanding shell collides with and sweeps up any surrounding interstellar matter. This creates a shock wave that compresses, heats, and ionizes the gas atoms, which then become visible as the emission nebula. Cygnus loop [′sig·nəs ‚lüp] (astronomy) A supernova remnant about 17,000 years old, and 30-40 parsecs across and probably about 770 parsecs distant that emits radio waves and x-rays as well as visible light. Also known as Veil Nebula.
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