Hot exozodis: cometary supply without trapping is unlikely to be the mechanism
arXiv:2209.11219 · doi:10.1093/mnras/stac2773
Abstract
Excess near-infrared emission is detected around one fifth of main-sequence stars, but its nature is a mystery. These excesses are interpreted as thermal emission from populations of small, hot dust very close to their stars (`hot exozodis'), but such grains should rapidly sublimate or be blown out of the system. To date, no model has fully explained this phenomenon. One mechanism commonly suggested in the literature is cometary supply, where star-grazing comets deposit dust close to the star, replenishing losses from grain sublimation and blowout. However, we show that this mechanism alone is very unlikely to be responsible for hot exozodis. We model the trajectory and size evolution of dust grains released by star-grazing comets, to establish the dust and comet properties required to reproduce hot-exozodi observations. We find that cometary supply alone can only reproduce observations if dust ejecta has an extremely steep size distribution upon release, and the dust-deposition rate is extraordinarily high. These requirements strongly contradict our current understanding of cometary dust and planetary systems. Cometary supply is therefore unlikely to be solely responsible for hot exozodis, so may need to be combined with some dust-trapping mechanism (such as gas or magnetic trapping) if it is to reproduce observations.
18 pages, 9 figures, accepted for publication in MNRAS
References in corpus (27)
- Transience of hot dust around sun-like stars
- Spitzer IRS Spectroscopy of IRAS-Discovered Debris Disks
- Evidence for the formation of comet 67P/Churyumov-Gerasimenko through gravitational collapse of a bound clump of pebbles
- Circumstellar material in the Vega inner system revealed by CHARA/FLUOR
- A near-infrared interferometric survey of debris-disc stars. IV. An unbiased sample of 92 southern stars observed in H-band with VLTI/PIONIER
- Planetesimal driven migration as an explanation for observations of high levels of warm, exozodiacal dust
- Solution to the debris disc mass problem: planetesimals are born small?
- A near-infrared interferometric survey of debris-disc stars. V. PIONIER search for variability
- Planet populations inferred from debris discs: insights from 178 debris systems in the ISPY, LEECH and LIStEN planet-hunting surveys
- First-light LBT nulling interferometric observations: warm exozodiacal dust resolved within a few AU of eta Corvi
- Vega's hot dust from icy planetesimals scattered inward by an outward-migrating planetary system
- Inner mean-motion resonances with eccentric planets: A possible origin for exozodiacal dust clouds
- Near-infrared emission from sublimating dust in collisionally active debris disks
- Exocomets size distribution in the Pictoris planetary system
- Porous dust grains in debris disks
- Exo-zodi modelling for the Large Binocular Telescope Interferometer
- Hot circumstellar material resolved around beta Pic with VLTI/PIONIER
- Constraints on the structure of hot exozodiacal dust belts
- Fomalhaut b could be massive and sculpting the narrow, eccentric debris disc, if in mean-motion resonance with it
- Gas trapping of hot dust around main-sequence stars
- A near-infrared interferometric survey of debris-disk stars. VII. The hot/warm dust connection
- Hot exozodiacal dust: an exocometary origin?
- Thermal Emission Spectroscopy of Single, Isolated Carbon Nanoparticles: Effects of Particle Size, Material, Charge, Excitation Wavelength, and Thermal History
- The influence of dust grain porosity on the analysis of debris disc observations
- The HOSTS survey: evidence for an extended dust disk and constraints on the presence of giant planets in the Habitable Zone of Leo
- First L band detection of hot exozodiacal dust with VLTI/MATISSE
- Modelling of mid-infrared interferometric signature of hot exozodiacal dust emission
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- Hot exozodiacal dust around Fomalhaut: The MATISSE perspective
- Interferometric Detection and Orbit Modeling of the Subcomponent in the Hot-dust System Tuc A: A Low-mass Star on an Eccentric Orbit in a Hierarchical-quintuple System
- VLTI/MATISSE observations of the hot dust around Pictoris: Observing faint objects with MATISSE