SIMBAD references

2005MNRAS.363L..81A - Mon. Not. R. Astron. Soc., 363, L81-L85 (2005/October-2)

Beryllium enhancement as evidence for accretion in a lithium-rich F dwarf.

ASHWELL J.F., JEFFRIES R.D., SMALLEY B., DELIYANNIS C.P., STEINHAUER A. and KING J.R.

Abstract (from CDS):

The early F dwarf star `J37' in the open cluster NGC 6633 shows an unusual pattern of photospheric abundances, including an order-of-magnitude enhancement of lithium and iron-peak elements, but an under-abundance of carbon. As a consequence of its thin convection zone these anomalies have been attributed to either radiative diffusion or the accretion of hydrogen-depleted material. By comparing high-resolution Very Large Telescope/UV-Visual Echelle Spectrograph spectra of J37 (and other F stars in NGC 6633) with syntheses of the Beii doublet region at 3131 Å, we establish that J37 also has a Be abundance [A(Be) = 3.0±0.5] that is at least 10 times the cosmic value. This contradicts radiative diffusion models that produce a Li over-abundance, as they also predict photospheric Be depletion. Instead, since Be is a highly refractory element, it supports the notion that J37 is the first clear example of a star that has accreted volatile-depleted material with a composition similar to chondritic meteorites, although some diffusion may be necessary to explain the low C and O abundances.

Abstract Copyright: 2005 RAS

Journal keyword(s): accretion, accretion discs - diffusion - stars: abundances - stars: atmospheres - stars: chemically peculiar - stars: evolution

Simbad objects: 5

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