Radial Distribution of Dust Grains Around HR 4796A

Abstract

We present high-dynamic-range images of circumstellar dust around HR 4796A that were obtained with MIRLIN at the Keck II telescope at lambda = 7.9, 10.3, 12.5 and 24.5 um. We also present a new continuum measurement at 350 um obtained at the Caltech Submillimeter Observatory. Emission is resolved in Keck images at 12.5 and 24.5 um with PSF FWHM's of 0.37" and 0.55", respectively, and confirms the presence of an outer ring centered at 70 AU. Unresolved excess infrared emission is also detected at the stellar position and must originate well within 13 AU of the star. A model of dust emission fit to flux densities at 12.5, 20.8, and 24.5 um indicates dust grains are located 4(+3/-2) AU from the star with effective size, 28+/-6 um, and an associated temperature of 260+/-40 K. We simulate all extant data with a simple model of exozodiacal dust and an outer exo-Kuiper ring. A two-component outer ring is necessary to fit both Keck thermal infrared and HST scattered-light images. Bayesian parameter estimates yield a total cross-sectional area of 0.055 AU^2 for grains roughly 4 AU from the star and an outer-dust disk composed of a narrow large-grain ring embedded within a wider ring of smaller grains. The narrow ring is 14+/-1 AU wide with inner radius 66+/-1 AU and total cross-sectional area 245 AU^2. The outer ring is 80+/-15 AU wide with inner radius 45+/-5 AU and total cross-sectional area 90 AU^2. Dust grains in the narrow ring are about 10 times larger and have lower albedos than those in the wider ring. These properties are consistent with a picture in which radiation pressure dominates the dispersal of an exo-Kuiper belt.

Accepted by Astrophysical Journal (Part1) on September 9, 2004. 13 pages, 10 figures, 2 tables

References in corpus (2)

• How many cosmological parameters?
• Modeling the Infrared Emission from the HR 4796A Disk

Cited by in corpus (36)

• The Debris Disk Around HR 8799
• Polarimetry with the Gemini Planet Imager: Methods, Performance at First Light, and the Circumstellar Ring around HR 4796A
• The Gemini NICI Planet-Finding Campaign: The Frequency of Giant Planets around Young B and A Stars
• Do Two Temperature Debris Disks Have Multiple Belts?
• Outer edges of debris discs: how sharp is sharp?
• Five steps in the evolution from protoplanetary to debris disk
• The Rise and Fall of Debris Disks: MIPS Observations of h and chi Persei and the Evolution of Mid-IR Emission from Planet Formation
• Complex Organic Materials in the Circumstellar Disk of HR 4796A
• Are debris disks self-stirred?
• The Dust Properties of Eight Debris Disk Candidates as Determined by Submillimeter Photometry
• Images of the Extended Outer Regions of the Debris Ring Around HR 4796 A
• Spitzer observations of the Orion OB1 association: second generation dust disks at 5-10 Myr
• Kuiper Belts Around Nearby Stars
• Resolved debris disk emission around eta Tel: a young Solar System or ongoing planet formation?
• The Formation and Evolution of Planetary Systems (FEPS): Discovery of an Unusual Debris System Associated with HD 12039
• SPITZER/IRAC-MIPS Survey of NGC2451A and B: Debris Disks at 50-80 million years
• On the Morphology and Chemical Composition of the HR 4796A Debris Disk
• The SHARDDS survey: first resolved image of the HD114082 debris disk in Lower Centaurus Crux with SPHERE
• An insight in the surroundings of HR4796
• High-Resolution Imaging of the Dust Disk around 49 Ceti
• Multi-Wavelength Modelling of the Beta Leo Debris Disc: 1, 2 or 3 planetesimal populations?
• Molecular hydrogen in the circumstellar environments of Herbig Ae/Be stars probed by FUSE
• Resolved Imaging of the HD191089 Debris Disc
• 12 and 18 micron images of dust surrounding HD 32297
• Formation and evolution of planetary systems: the impact of high angular resolution optical techniques
• New constraints on the dust surrounding HR 4796A
• The Gemini NICI Planet-Finding Campaign: The Offset Ring of HR 4796 A
• Dust production in the debris disk around HR 4796 A
• Effects of photophoresis on the dust distribution in a 3D protoplanetary disc
• Effects of photophoresis on the evolution of transitional circumstellar disks
• A near-infrared interferometric survey of debris-disk stars. VII. The hot/warm dust connection
• Dynamical models to explain observations with SPHERE in planetary systems with double debris belts
• Asymmetric Heating of the HR 4796A Dust Ring Due to Pericenter Glow
• Complex Organic Materials in the HR 4796A Disk?
• Infrared Spectroscopy of HR 4796A's Bright Outer Cometary Ring + Tenuous Inner Hot Dust Cloud
• PDS 70 unveiled by star-hopping: total intensity, polarimetry and mm-imaging modeled in concert