Long-Term Collisional Evolution of Debris Disks
By T. Löhne, A. Krivov, J. Rodmann. 2007
157 citations recorded by the source corpus.
IR surveys indicate that the dust content in debris disks gradually declines with stellar age. We simulated the long-term collisional depletion of debris disks around solar-type (G2 V) stars with our collisional code. The numerical results were supplemented by, and interpreted through, a new analytic model. General scaling rules for the disk evolution are suggested. The timescale of the collisional evolution is inversely proportional to the initial disk mass and scales with radial distance as r4.3 and with eccentricities of planetesimals as e−2.3. Further, we show that at actual ages of debris disks between 10 Myr and 10 Gyr, the decay laws of the dust mass and the total disk mass are different. The reason is that the collisional lifetime of planetesimals is size dependent. At any moment, there exists a transitional size, which separates larger objects that still retain the ``primordial'' size distribution set in the growth phase from smaller objects whose size distribution is already set by disruptive collisions. The dust mass and its decay rate evolve as that transition affects objects of ever larger sizes. Under standard assumptions, the dust mass, fractional luminosity, and thermal fluxes all decrease as tξ with ξ = − 0.3 to –0.4. Specific decay laws of the total disk mass and the dust mass, including the value of ξ, largely depend on a few model parameters, such as the critical fragmentation energy as a function of size, the primordial size distribution of largest planetesimals, and the characteristic eccentricity and inclination of their orbits. With standard material prescriptions and a distribution of disk masses and extents, a synthetic population of disks generated with our analytic model agrees quite well with the observed Spitzer MIPS statistics of 24 and 70 μm fluxes and colors versus age.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/619cd90550636350150812faf275bc91b2318bf6
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In Astronomy and Astrophysics
Citations in the corpus
- Debris disks as signposts of terrestrial planet formation (2011, methodology): “11 of Löhne et al. 2008; Kenyon & Bromley 2008, 2010; Krivov 2010).”
- The Complete Census of 70 μm-Bright Debris Disks within “The Formation and Evolution of Planetary Systems” Spitzer Legacy Survey of Sun-like Stars (2007, background): “Another comparison that can be made is to the planetesimal formation and early debris ‘‘self-stirring’’ models of Kenyon & Bromley (2005), which predict a peak in f between 10 and 100Myr, rather than the monotonic steady decay of Dominik & Decin (2003), Wyatt et al. (2007), or Löhne et al. (2008).”
- Variations on Debris Disks: Icy Planet Formation at 30-150 AU for 1-3 M☉ Main-Sequence Stars (2008, background): “Dominik & Decin (2003), Wyatt et al. (2007a), and Löhne et al. (2008) show that collisional evolution in a belt of high-velocity planetesimals naturally produces a dust luminosity that declines roughly inversely with time (see also Kenyon & Bromley 2002a, 2004b, 2005), which explains the observed…”