TIME EVOLUTION OF VISCOUS CIRCUMSTELLAR DISKS DUE TO PHOTOEVAPORATION BY FAR-ULTRAVIOLET, EXTREME-ULTRAVIOLET, AND X-RAY RADIATION FROM THE CENTRAL STAR

By U. Gorti, K. Dullemond, D. Hollenbach. 2009

184 citations recorded by the source corpus.

We present the time evolution of viscously accreting circumstellar disks as they are irradiated by ultraviolet and X-ray photons from a low-mass central star. Our model is a hybrid of a one-dimensional (1D) time-dependent viscous disk model coupled to a 1+1D disk vertical structure model used for calculating the disk structure and photoevaporation rates. We find that disks of initial mass 0.1 M☉ around ∼1 M☉ stars survive for ∼4 × 106 yr, assuming a viscosity parameter α = 0.01, a time-dependent FUV luminosity LFUV ∼ 10−2–10−3 L☉ and with X-ray and EUV luminosities LX ∼ LEUV ∼ 10−3 L☉. We find that FUV/X-ray-induced photoevaporation and viscous accretion are both important in depleting disk mass. Photoevaporation rates are most significant at ∼1–10 AU and at ≳30 AU. Viscosity spreads the disk which causes mass loss by accretion onto the central star and feeds mass loss by photoevaporation in the outer disk. We find that FUV photons can create gaps in the inner, planet-forming regions of the disk (∼1–10 AU) at relatively early epochs in disk evolution while disk masses are still substantial. EUV and X-ray photons are also capable of driving gaps, but EUV can only do so at late, low accretion-rate epochs after the disk mass has already declined substantially. Disks around stars with predominantly soft X-ray fields experience enhanced photoevaporative mass loss. We follow disk evolution around stars of different masses, and find that disk survival time is relatively independent of mass for stars with M*≲ 3 M☉; for M*≳ 3 M☉ the disks are short-lived (∼105 yr).

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b9380de7626af80c8f44c6eb8437d5375f3a29ea

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In Astronomy and Astrophysics

1. J. Owen
2. S. Andrews
3. D. Wilner
4. A. Hughes
5. T. Birnstiel
6. C. Dullemond
7. C. Qi
8. Barbara Ercolano

Citations in the corpus

• On the theory of disc photoevaporation (2011, background): “Furthermore, the calculations of Gorti et al. (2009) indicate that mass-depleted discs drive more efficient flows (as in their calculations the mass loss remains constant as the accretion rate – and thus FUV luminosity – falls).”
• RESOLVED IMAGES OF LARGE CAVITIES IN PROTOPLANETARY TRANSITION DISKS (2011, background): “In models that consider only UV irradiation, the wind plays a minor role in the evolution of a disk structure over most of its lifetime (Alexander et al. 2006b; Gorti et al. 2009).”
• PROTOPLANETARY DISK STRUCTURES IN OPHIUCHUS. II. EXTENSION TO FAINTER SOURCES (2010, methodology): “Recent theoretical calculations have suggested that the high-energy (particularly far-ultraviolet, or FUV) irradiation of the disk surface by the central star can drive significant mass loss from large disk radii (R > 30AU) in a photoevaporative flow (Gorti & Hollenbach 2009; Gorti et al. 2009).”
• HOW THERMAL EVOLUTION AND MASS-LOSS SCULPT POPULATIONS OF SUPER-EARTHS AND SUB-NEPTUNES: APPLICATION TO THE KEPLER-11 SYSTEM AND BEYOND (2012, methodology): “Moreover, using a more typical disk lifetime of 105 yr (Gorti et al. 2009) and including the effect of cooling the core imply that Kepler-11b was <1% H/He at formation.”
• Protoplanetary disc evolution and dispersal: the implications of X-ray photoevaporation (2010, background): “…extreme ultraviolet radiation -EUV- (Clarke et al 2001; Alexander et al 2006a,b; Richling & Yorke 2000), X-ray radiation (Alexander et al. 2004; Ercolano et al 2008b, 2009; Gorti & Hollenbach 2009, Owen et al. 2010) and far ultraviolet radiation -FUV- (Gorti & Hollenbach 2009; Gorti et al. 2009).”