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

By Isabelle Baraffe, G. Chabrier. 2010

176 citations recorded by the source corpus.

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.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/5506372b6c0b84e7c2bceace81a64cb7787b98a1

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Citations in the corpus

Improved angular momentum evolution model for solar-like stars (2013, methodology): “Robust inferences regarding the history of lithium depletion in solar-type stars would benefit from a more physical modeling of the processes involved (e.g., Charbonnel & Talon 2005; Baraffe & Chabrier 2010; Do Nascimento et al. 2010; Eggenberger et al. 2010, 2012).”
Solar Neutrinos: Status and Prospects (2012, unknown): “…simulations of the contraction of the protosolar nebula (Wuchterl & Klessen 2001) and stellar models that include episodic accretion during the pre-main-sequence phase with large mass accretion rates (Baraffe & Chabrier 2010), the Sun may have avoided the fully convective phase altogether.”
Star Formation in the Milky Way and Nearby Galaxies (2012, methodology): “Assumptions about accretion and initial conditions may also have substantial consequences for the usual methods of determining ages of young stars (Baraffe et al. 2009; Baraffe & Chabrier 2010; Hosokawa et al. 2011).”
Extrasolar planet population synthesis - IV. Correlations with disk metallicity, mass, and lifetime (2012, background): “On theoretical bases, several mechanism can enhance lithium depletion (e.g. Baraffe & Chabrier 2010).”
AN OPTICAL SPECTROSCOPIC STUDY OF T TAURI STARS. I. PHOTOSPHERIC PROPERTIES (2014, background): “The limited affect of accretion histories on pre-main sequence evolution The pre-main sequence models of Baraffe & Chabrier (2010) demonstrate that stars contract faster if they form primarily by large accretion events with rates of > 10−4 M⊙ yr −1, as opposed to steady accretion throughout the…”
DIRECT IMAGING OF A COLD JOVIAN EXOPLANET IN ORBIT AROUND THE SUN-LIKE STAR GJ 504 (2013, background): “(Baraffe & Chabrier 2010), and the importance of nonlocal thermodynamic equilibrium abundance corrections (Takeda & Kawanomoto 2005), make it difficult to obtain a reliable age estimate from lithium abundances.”
The stellar and sub-stellar IMF of simple and composite populations (2011, background): “The uncertainties due to such processes have been partially discussed though (Baraffe et al. 2002, 2009; Baraffe & Chabrier 2010).”
VARIABLE PROTOSTELLAR ACCRETION WITH EPISODIC BURSTS (2015, methodology): “In this work, the properties of the forming protostar are calculated using a stellar evolution code described in Baraffe & Chabrier (2010).”
SOLAR MODELS WITH ACCRETION. I. APPLICATION TO THE SOLAR ABUNDANCE PROBLEM (2011, background): “…metal comparable to the excess of metal sequestered in the planets (Haxton & Serenelli 2008); in recent models of the assembly of low mass stars (Baraffe & Chabrier 2010); and in claims that the Sun has an abundance pattern of metals that correlates with metal condensation temperatures,…”
Accretion onto Pre-Main-Sequence Stars (2016, methodology): “This type of initial condition was used by Baraffe & Chabrier (2010) and Baraffe et al. (2012) in an attempt to explain observations of objects in star-forming regions that appear to be much older than the bulk of the population.”