Transience of Hot Dust around Sun-like Stars

By M. C. Wyatt, Roger M. H. Smith, J. Greaves, C. Beichman, G. Bryden, C. Lisse. 2006

274 citations recorded by the source corpus.

In this paper a simple model for the steady state evolution of debris disks due to collisions is developed and confronted with the properties of the emerging population of seven Sun-like stars that have hot dust at <10 AU. The model shows that there is a maximum possible disk mass at a given age, since more massive primordial disks process their mass faster. The corresponding maximum dust luminosity is fmax = 0.16 × 10-3r7/3t, where r is disk radius in AU and tage is system age in Myr. The majority (4/7) of the hot disks exceed this limit by ≫1000 and so cannot be the products of massive asteroid belts; rather, the following systems must be undergoing transient events characterized by an unusually high dust content near the star: η Corvi, HD 69830, HD 72905, and BD +20 307. It is also shown that the hot dust cannot originate in a recent collision in an asteroid belt, since there is also a maximum rate at which collisions of sufficient magnitude to reproduce a given dust luminosity can occur. The planetesimal belt feeding the dust in these systems must be located farther from the star than the dust, typically at ≫2 AU. Other notable properties of the four hot dust systems are as follows: two also have a planetesimal belt at >10 AU (η Corvi and HD 72905); one has three Neptune mass planets at <1 AU (HD 69830); all exhibit strong mid-IR silicate features. We consider the most likely origin for this transient dust to be a dynamical instability that scattered planetesimals inward from a more distant planetesimal belt in an event akin to the late heavy bombardment in our own system, the dust being released from such planetesimals in collisions and sublimation.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/4598d53cc3304164ef019927d74723585d96947b

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Citations in the corpus

COMETARY ORIGIN OF THE ZODIACAL CLOUD AND CARBONACEOUS MICROMETEORITES. IMPLICATIONS FOR HOT DEBRIS DISKS (2009, background): “It has been argued that some of the observed brightest hot disks, such as HD 69830, HD 72905, HD 23514, η Corvi, and BD+20307, cannot be explained by assuming that they are produced by the collisional grinding of the local population of asteroids (Wyatt et al. 2007).”
PROBING FOR EXOPLANETS HIDING IN DUSTY DEBRIS DISKS: DISK IMAGING, CHARACTERIZATION, AND EXPLORATION WITH HST/STIS MULTI-ROLL CORONAGRAPHY (2014, background): “However, because these dynamical processes occur on much shorter timescales than a host star’s lifetime, a quasi-equilibrium condition may exist where dusty debris is continuously generated through collisions and the net solid mass declines with age (Wyatt et al. 2007a, 2007b; Wyatt 2008).”
POLLUTION OF SINGLE WHITE DWARFS BY ACCRETION OF MANY SMALL ASTEROIDS (2008, background): “Even the presence of warm dust at a few AU from the star does not tightly constrain the parent body populations (see Wyatt et al. 2007).”
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…”
Steady State Evolution of Debris Disks around A Stars (2007, methodology): “This limit is given in equation (14) and was used in Wyatt et al. (2007) to show that several of the disks found < 10 AU around sun-like stars must be transient.”
Debris disks as signposts of terrestrial planet formation (2011, methodology): “For each population of bodies (asteroidal and cometary), we calculate the collisional timescale tc, which is a function of the particle size D as well as the orbital properties of the population (Wyatt et al. 1999, 2007a).”
FORMATION AND EVOLUTION OF PLANETARY SYSTEMS: PROPERTIES OF DEBRIS DUST AROUND SOLAR-TYPE STARS (2008, methodology): “6) because of additional assumptions about how physical parameters vary with radius in the latter model (see Wyatt et al. 2007a).”
Circumstellar Debris and Pollution at White Dwarf Stars (2016, background): “…and hence not ruled out empirically (Wyatt, 2008), owing to collisional evolution, massive disks within 10 AU are not expected to survive beyond a few Myr, and should be depleted by orders of magnitude by 100 Myr, well before the post-main sequence (Wyatt et al., 2007; Bonsor & Wyatt, 2010).”
Long-Term Collisional Evolution of Debris Disks (2007, methodology): “This discrepancy is probably a result of the particle-in-a-box assumptions made by Wyatt et al. (2007a) in derivation of Eq.”