Complex Organic Materials in the HR 4796A Disk?

Abstract

The red spectral shape of the visible to near infrared reflectance spectrum of the sharply-edged ring-like disk around the young main sequence star HR 4796A was recently interpreted as the presence of tholin-like complex organic materials which are seen in the atmosphere and surface of Titan and the surfaces of icy bodies in the solar system. However, we show in this Letter that porous grains comprised of common cosmic dust species (amorphous silicate, amorphous carbon, and water ice) also closely reproduce the observed reflectance spectrum, suggesting that the presence of complex organic materials in the HR 4796 disk is still not definitive.

6 pages, 3 figures; To be published in The Astrophysical Journal Letters

References in corpus (15)

• How Observations of Circumstellar Disk Asymmetries Can Reveal Hidden Planets: Pericenter Glow and its Application to the HR 4796 Disk
• NICMOS Imaging of the HR 4796A Circumstellar Disk
• Mid-infrared Imaging of a Circumstellar Disk Around HR 4796: Mapping the Debris of Planetary Formation
• A dust disk surrounding the young A star HR4796A
• Outer edges of debris discs: how sharp is sharp?
• Deep 10 and 18 micron Imaging of the HR 4796A Circumstellar Disk: Transient Dust Particles & Tentative Evidence for a Brightness Asymmetry
• Sub-mm observations and modelling of Vega type stars
• 8--13 um spectroscopy of YSOs: Evolution of the silicate feature
• Complex Organic Materials in the Circumstellar Disk of HR 4796A
• Modeling the Infrared Emission from the HD 141569A Disk
• Modeling the Infrared Emission from the HR 4796A Disk
• Dust Distribution in Gas Disks. A Model for the Ring Around HR 4796A
• Radial Distribution of Dust Grains Around HR 4796A
• Are Giant Planets Forming Around HR 4796A?
• Forming the Dusty Ring in HR 4796A

Cited by in corpus (12)

• Debris Disks: Structure, Composition, and Variability
• Polarimetry with the Gemini Planet Imager: Methods, Performance at First Light, and the Circumstellar Ring around HR 4796A
• An icy Kuiper-Belt around the young solar-type star HD 181327
• Speckle Suppression Through Dual Imaging Polarimetry, and a Ground-Based Image of the HR 4796A Circumstellar Disk
• On the Morphology and Chemical Composition of the HR 4796A Debris Disk
• Formation and evolution of planetary systems: the impact of high angular resolution optical techniques
• The Gemini NICI Planet-Finding Campaign: The Offset Ring of HR 4796 A
• Infrared Spectroscopy of HR 4796A's Bright Outer Cometary Ring + Tenuous Inner Hot Dust Cloud
• Complex Organic and Inorganic Compounds in Shells of Lithium-rich K Giant Stars
• Light Scattering and Thermal Emission by Primitive Dust Particles in Planetary Systems
• Searching for Biosignatures in Exoplanetary Impact Ejecta
• A Multiband Study of the HR 4796A Disk in the Optical Using MagAO-X