Age Dependence of the Vega Phenomenon: Theory

By C. Dominik, G. Decin. 2003

196 citations recorded by the source corpus.

In a separate paper, we have reexamined the observations of IR excess obtained with the Infrared Space Observatory satellite and discussed the ages of stars with excess. The amount of dust (measured by the luminosity fraction fd = LIR/L*) seen around main-sequence stars of different ages shows several interesting trends. To discuss these results in the context of a physical model, we develop in this paper an analytical model for the dust production in Vega-type systems. Previously it has been claimed that a power-law slope of about -2 in the diagram plotting amount of dust versus time could be explained by a simple collisional cascade. We show that such a cascade in fact results in a power law fd ∝ t-1 if the dust removal processes are dominated by collisions. A power law fd ∝ t-2 only results when the dust removal processes become dominated by Pointing-Robertson drag. This might be the case in the Kuiper Belt of our own solar system, but it is certainly not the case in any of the observed disks. A steeper slope can, however, be created by including continuous stirring into the models. We show that the existence of both young and old Vega-like systems with large amounts of dust (fd ≃ 10-3) can be explained qualitatively by Kuiper Belt-like structures with delayed stirring. Finally, the absence of young stars with intermediate amounts of dust might be due to the fact that stirring due to planet formation may not be active in young low-mass disks. The considerations in this paper support the picture of simultaneous stirring and dust production proposed by Kenyon and Bromley.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/a4e224d37484793629e3e8ecdc4ebe003cc6405e

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. K. Luhman
2. Eric Mamajek
3. L. Hillenbrand
4. S. Kenyon
5. M. C. Wyatt
6. B. Bromley
7. Philip Armitage
8. B. Zuckerman

In Instrumentation

1. L. Hillenbrand
2. Eric Mamajek
3. K. Luhman
4. S. Kenyon
5. M. C. Wyatt
6. B. Bromley
7. A. Mustill
8. Philip Armitage

In Statistical and Nonlinear Physics

1. A. Mustill
2. M. C. Wyatt
3. D. Hollenbach
4. G. Bryden
5. T. Löhne
6. Eric Mamajek
7. A. Moro-Martin
8. Th. Henning

Citations in the corpus

• The Insignificance of P-R drag in detectable extrasolar planetesimal belts (2005, background): “It has been noted by several authors that the collisional lifetime of dust grains in the well studied debris disks is shorter than that of P-R drag (e.g., Backman & Paresce 1993; Wilner et al. 2002; Dominik & Decin 2003), a condition which means that P-R drag can be ignored in these systems.”
• Debris disks as signposts of terrestrial planet formation (2011, methodology): “…population are drawn from previous studies that fit models of the collisional evolution of planetesimal belts to the statistics for the evolution of debris disks (Dominik & Decin 2003; Krivov et al. 2005, 2006; Wyatt et al. 2007b; Löhne et al. 2008; Wyatt 2008; Krivov 2010; Kains et al. 2011).”
• Nearby Debris Disk Systems with High Fractional Luminosity Reconsidered (2006, methodology): “A new generation of theoretical models has been developed to explain the temporal evolution of debris disks (Kenyon&Bromley 2002; Dominik & Decin 2003; Kenyon & Bromley 2004).”
• Spitzer IRS Spectroscopy of IRAS-discovered Debris Disks (2006, background): “This model predicts a t−0.6 to t−0.35 decay of the fractional infrared luminosity for the whole debris disk at ages of 10 Myr to 1 Gyr, depending on the tensile strength of the grains, a somewhat more shallow evolution of the fractional infrared luminosity than inferred by Dominik & Decin (2003).”
• Decay of Planetary Debris Disks (2005, background): “Dust in these later-stage disks must be resupplied because the lifetimes for the dust grains against loss via radiation pressure, Poynting-Robertson drag, and collisional destruction are quite short (e.g., Backman & Paresce 1993; Lagrange et al. 2000; Dominik & Decin 2003).”
• Debris disc stirring by secular perturbations from giant planets (2009, background): “The dust grains have only a short lifetime compared to the ageof the star, being ground down in collisional processes until they are small enough to be ejected from the system by radiation pressu (Dominik & Decin 2003; Wyatt 2005).”
• 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, methodology): “Similar analysis by Dominik & Decin (2003) and Wyatt (2005) of previously known bright debris disks has led to similar conclusions: that they are all collision dominated.”
• Frequency of Debris Disks around Solar-Type Stars: First Results from a Spitzer MIPS Survey (2005, background): “Dominik & Decin (2003) find that theoretical models of debris disk evolution tend to evolve toward the same final dust distributions over long enough time scales.”
• Steady State Evolution of Debris Disks around A Stars (2007, methodology): “…Decin et al. (2003) noted that the maximum luminosity of debris disks remains constant at f ≈ 10−3 even for the oldest stars, and this was explained by Dominik & Decin (2003) as a consequence of delayed stirring, in which dust is not produced in the planetesimal belt until Pluto-sized objects form…”
• FORMATION AND EVOLUTION OF PLANETARY SYSTEMS: PROPERTIES OF DEBRIS DUST AROUND SOLAR-TYPE STARS (2008, methodology): “We use the quasi-steady state collisional model developed by Dominik & Decin (2003) and described in §5 to project forward the evolution of the FEPS debris disks.”
• Long-Term Collisional Evolution of Debris Disks (2007, methodology): “In an attempt to gain theoretical understanding of the observed evolution, Dominik & Decin (2003) assumed that equally-sized “comets” produce dust through a cascade of subsequent collisions among ever-smaller objects.”
• Collisional processes and size distribution in spatially extended debris discs (2007, background): “Although cometary evaporation could also be a possibility (Li & Greenberg 1998), the most likely dust production mechanism is collisional erosion of bigger solid objects (Artymowicz 1997; Dominik & Decin 2003).”
• 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…”
• Dust distributions in debris disks: effects of gravity, radiation pressure and collisions (2006, methodology): “From the mass loss rate of a system in a steady state, Ṁ = −cM M2, where cM is a constant, we can deduce the dependence of mass on time: M(t) = M0/[1 + cM M0 · (t − t0)], (32) where M0 = M(t0) (cf. Dominik & Decin 2003).”