The chemical composition of three Lambda Bootis stars

Journal Article · Thu Nov 01 00:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169334· OSTI ID:6062455

Venn, K A; Lambert, D L ^[1]

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1. Texas Univ., Austin (USA)

Abundance analyses are reported for three certain members (Lambda Boo, 29 Cyg, Pi1 Ori) of the class of rapidly rotating, metal-poor A-type stars known as Lambda Bootis stars. Model atmosphere analysis of high-resolution, high signal-to-noise spectra shows that the metal deficiencies are more severe than previously reported: Fe/H = -2.0, -1.8, -1.3 for Lambda Boo, 29 Cyg, and Pi1 Ori, respectively. Other metals (Mg, Ca, Ti, and Sr) are similarly underabundant, with Na often having a smaller underabundance. C, N, O, and S have near-solar abundances. Vega is shown to be a mild Lambda Boo star. The abundance anomalies of the Lambda Boo stars resemble those found for the interstellar gas in which the metals are depleted through formation of interstellar grains. It is suggested that the Lambda Boo stars are created when circumstellar (or interstellar) gas is separated from the grains and accreted by the star. The bulk of the interstellar grains comprises a circumstellar cloud or disk that is detectable by its infrared radiation. 67 refs.

• OSTI ID: 6062455
• Journal Information: Astrophysical Journal; (USA), Vol. 363; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
STARS
CHEMICAL COMPOSITION
CARBON
COSMIC GASES
ELEMENT ABUNDANCE
INFRARED RADIATION
INTERSTELLAR GRAINS
INTERSTELLAR SPACE
MAIN SEQUENCE STARS
METALS
NITROGEN
OXYGEN
ROTATION
STAR ACCRETION
STELLAR ATMOSPHERES
SULFUR
ABUNDANCE
ATMOSPHERES
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
GASES
MOTION
NONMETALS
PARTICLES
RADIATIONS
SPACE
STAR EVOLUTION
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources