Timescale of mass accretion in pre-main-sequence stars

By D. Fedele, M. V. D. Ancker, Th. Henning, R. Jayawardhana, Joana M. Oliveira. 2009

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We present the initial result of a large spectroscopic survey aimed at measuring the timescale of mass accretion in young, pre-main-sequence stars in the spectral type range K0-M5. Using multi-object spectroscopy with VIMOS at the VLT we identified the fraction of accreting stars in a number of young stellar clusters and associations of the ages of between 1-30 Myr. The fraction of accreting stars decreases from ~60% at 1.5-2 Myr to ~2% at 10 Myr. No accreting stars are found after 10 Myr at a sensitivity limit of 10 -11 M ⊙ yr -1 We compared the fraction of stars showing ongoing accretion (f acc ) to the fraction of stars with near-to-mid infrared excess (f IRAC ). In most cases we find f acc < F IRAC , i.e., mass accretion appears to cease (or drop below detectable level) earlier than the dust is dissipated in the inner disk. At 5 Myr, 95% of the stellar population has stopped accreting material at a rate of ≳10 -11 M ⊙ yr -1 while ~20% of the stars show near-infrared excess emission. Assuming an exponential decay, we measure a mass accretion timescale (τ acc ) of 2.3 Myr, compared to a near-to-mid infrared excess timescale (τ IRAC ) of 3 Myr. Planet formation and/or migration, in the inner disk might be a viable mechanism to halt further accretion onto the central star on such a short timescale.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/e4647f26269887052bfbfcee0477257211f09024

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Citations in the corpus

Accretion onto Pre-Main-Sequence Stars (2016, background): “F or p er so na l u se o nl y. 2007), gas (e.g., Pascucci et al. 2006, Ingleby et al. 2009), or accretion rates (Fedele et al. 2010).”
The star formation history and accretion-disc fraction among the K-type members of the Scorpius–Centaurus OB association (2016, background): “Observations of young clusters and associations of ages from ∼1 to >100 Myr have given strong indication that the protoplanetary disk dispersal timescale is very short, with an e-folding time of ∼ 2.5 Myr (Mamajek 2009; Fedele et al. 2010).”
ALMA SURVEY OF LUPUS PROTOPLANETARY DISKS. I. DUST AND GAS MASSES (2016, background): “Although a spectroscopic survey by Fedele et al. (2010) showed that inner gas disk lifetimes are shorter than dust dissipation timescales, sensitive interferometers are needed to probe bulk gas content while avoiding confusion with cloud emission.”
Characterization of exoplanets from their formation - II. The planetary mass-radius relationship (2012, background): “…disk is on one hand the observational progress that has been made in the last few years also in this field (e.g. Andrews et al. 2009, 2010; Fedele et al. 2010), but also the theoretical result that the disk structure is very important for the final properties of a synthetic planetary…”
Why do protoplanetary disks appear not massive enough to form the known exoplanet population? (2018, background): “Similarly, in clusters younger than 2 Myr, &60–80% of stars possess protoplanetary disks (e.g., Fedele et al. 2010).”
Extrasolar planet population synthesis - IV. Correlations with disk metallicity, mass, and lifetime (2012, background): “Observations of disks around young stars have provided us with knowledge of the distributions of disk masses (Beckwith & Sargent 1996; Andrews et al. 2009), disk sizes (McCaughrean & Odell 1996; Andrews et al. 2010) and lifetimes (Haisch et al. 2001; Fedele et al. 2010).”
Chemical enrichment of giant planets and discs due to pebble drift (2017, background): “E P] 9 M ay 2 01 which is long compared with the disc’s lifetime (a few Myr, Haisch et al. 2001; Currie et al. 2009; Fedele et al. 2010; Meng et al. 2017).”
Protoplanetary disk lifetimes vs stellar mass and possible implications for giant planet populations (2015, result): “Their results, in good agreement with previous estimates (Haisch et al. 2001; Hernández et al. 2007b, 2008; Mamajek 2009; Fedele et al. 2010; Murphy et al. 2013) served as a benchmark to test the reliability and robustness of the sample and methods used in R14.”
Protoplanetary Disks and Their Evolution (2011, background): “Using the equivalent widths and velocity profiles of the Hα line to identify accretors, Fedele et al. (2010) recently studied the fractions of accreting objects in stellar clusters with ages in the 1−50Myr range.”
Ring shaped dust accumulation in transition disks (2012, background): “Decrease of mass accretion rate (Sicilia-Aguilar et al. 2010; Fedele et al. 2010), and near-infrared excess with time (Hernández et al. 2007; Andrews et al. 2011b) indicate that disks have a range of lifetimes from 1 to 10 Myr.”
PROBING FOR EXOPLANETS HIDING IN DUSTY DEBRIS DISKS: DISK IMAGING, CHARACTERIZATION, AND EXPLORATION WITH HST/STIS MULTI-ROLL CORONAGRAPHY (2014, background): “…amounts of dust and little residual gas occurs over the first ∼10 Myr of the host star’s lifetime, with warm dust being rare in systems after ∼3 Myr (Haisch et al. 2001), gas being rare after 5–10 Myr, and stellar mass accretion declining to ∼10−11 M yr−1 over the same epoch (Fedele et al. 2010).”
ALMA continuum observations of the protoplanetary disk AS 209. Evidence of multiple gaps opened by a single planet (2017, background): “…is challenged by dust migration: according to dust evolution models such large dust grains are expected to drift towards the star in much less than a Myr (e.g., Takeuchi et al. 2005; Brauer et al. 2008), which is difficult to reconcile with disk lifetimes (a few Myr, e.g., Fedele et al. 2010).”