helium star
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Helium star — A helium star is a hypothetical star that could occur if two helium white dwarfs with a combined mass of at least 0.3 solar masses collide with a lifetime of a few hundred million years. As this would occur in the degenerate era of the universe,… … Wikipedia
Helium flash — A helium flash is the runaway fusion of helium in the core of low mass stars of less than about 2.25 solar masses and greater than about 0.5 solar mass, or on the surface of an accreting white dwarf star. They may also occur in the outer layers… … Wikipedia
helium variable — noun A star in which the strength of the helium absorption lines vary periodically; at times appearing to be a helium star … Wiktionary
Star lifting — is any of several hypothetical processes by which a highly advanced civilization (at least Kardashev II) could remove a substantial portion of a star s matter in a controlled manner for other uses. The term appears to have been coined by David… … Wikipedia
Helium fusion — is a kind of nuclear fusion, with the nuclei involved being helium.The fusion of helium 4 nuclei (alpha particles) is known as the triple alpha process, because fusion of just two helium nuclei only produces beryllium 8, which is unstable and… … Wikipedia
Star formation — is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star… … Wikipedia
star — starless, adj. /stahr/, n., adj., v., starred, starring. n. 1. any of the heavenly bodies, except the moon, appearing as fixed luminous points in the sky at night. 2. Astron. any of the large, self luminous, heavenly bodies, as the sun, Polaris,… … Universalium
Star — For other uses, see Star (disambiguation) … Wikipedia
Helium — otherusesHelium (He) is a colorless, odorless, tasteless, non toxic, inert monatomic chemical element that heads the noble gas group in the periodic table and whose atomic number is 2. Its boiling and melting points are the lowest among the… … Wikipedia
star cluster — Astron. a number of stars of common origin held together as a group by gravitational attraction. Cf. globular cluster, open cluster, stellar association. * * * ▪ astronomy Introduction either of two general types of stellar assemblages held… … Universalium
