CW Leonis

CW Leonis is a carbon-rich asymptotic giant branch star in Leo, losing mass into a dusty, molecule-rich envelope that shines exceptionally brightly in infrared light.

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Asymptotic giant branch: A late stellar evolutionary phase in which a star develops an inert core, alternating nuclear-burning shells, and a cool, extended atmosphere. CW Leonis is a highly evolved star in this phase.
Leo (constellation): A constellation of the zodiac, recognizable by its pattern of stars and located along the ecliptic. CW Leonis lies in the direction of this constellation.
Submillimeter astronomy: Astronomy using electromagnetic radiation between the far-infrared and microwave bands. Submillimeter observations trace cool dust and molecules in the outer envelope.
IRC+10216: The catalog designation commonly used for CW Leonis, derived from its discovery in an infrared source catalog. This name appears frequently in studies of the star’s infrared-bright envelope.
Stellar mass loss: The process by which a star loses matter to its surroundings through winds, eruptions, or other outflows. A dense outflow from CW Leonis supplies its surrounding envelope.
Stellar evolution: The changes in a star’s structure and properties over time, driven chiefly by nuclear fuel consumption and gravity. Its late giant-star state is one stage in stellar evolution.
Molecular spectroscopy: The study of how molecules absorb or emit radiation at characteristic frequencies. Spectral lines in the envelope identify its molecules and physical conditions.
OH/IR star: A highly obscured late-type giant identified through hydroxyl maser emission and strong infrared radiation. CW Leonis is a carbon-rich infrared source, unlike the oxygen-rich stars typical of this class.
Circumstellar envelope: Gas and dust surrounding a star, usually formed from matter expelled by stellar winds. Its envelope absorbs starlight and reradiates much of the energy in infrared.
Carbon–oxygen ratio: The relative abundance of carbon and oxygen in stellar material, which strongly influences molecule formation in cool atmospheres. Carbon exceeds oxygen in CW Leonis’s atmosphere, favoring carbon-bearing molecules.