Query : 2010A&A...521A..44B

2010A&A...521A..44B - Astronomy and Astrophysics, volume 521, A44-44 (2010/10-1)

Effect of episodic accretion on the structure and the lithium depletion of low-mass stars and planet-hosting stars.


Abstract (from CDS):

Following up our recent analysis devoted to the impact of non steady accretion on the location of young low-mass stars or brown dwarfs in the Herzsprung-Russell diagram, we perform a detailed analysis devoted to the effect of burst accretion on the internal structure of low-mass and solar type stars. We find that episodic accretion can produce objects with significantly higher central temperatures than the ones of the non accreting counterparts of same mass and age. As a consequence, lithium depletion can be severely enhanced in these objects. This provides a natural explanation for the unexpected level of lithium depletion observed in young objects for the inferred age of their parent cluster. These results confirm the limited reliability of lithium abundance as a criterion for assessing or rejecting cluster membership. They also show that lithium is not a reliable age indicator, because its fate strongly depends on the past accretion history of the star. Under the assumption that giant planets primarily form in massive disks prone to gravitational instability and thus to accretion burst episodes, the same analysis also explains the higher Li depletion observed in planet hosting stars. At last, we show that, depending on the burst rate and intensity, accretion outbursts can produce solar mass stars with lower convective envelope masses, at ages less than a few tens of Myr, than predicted by standard (non or slowly accreting) pre-main sequence models. This result has interesting, although speculative, implications for the recently discovered depletion of refractory elements in the Sun.

Abstract Copyright:

Journal keyword(s): stars: formation - stars: low-mass - stars: abundances - accretion, accretion disks

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 Cl Melotte 22 OpC 03 46 24 +24 06.8           ~ 3227 0
2 NAME Orion Nebula Cluster OpC 05 35.0 -05 29           ~ 2173 1
3 Cl Collinder 69 OpC 05 35 10 +09 48.8     2.8     ~ 277 0
4 NAME sigma Orionis Cluster MGr 05 38 42 -02 36.0           ~ 526 0
5 IC 4665 OpC 17 46 13 +05 36.9           ~ 340 0

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