Extent of Excess Far Infrared Emission around Luminosity Class III Stars

Abstract

With the Infrared Space Observatory, we conducted 3x3-pixel imaging photometry of twelve luminosity class III stars, which were previously presumed to have dust particles around them, at far infrared wavelengths (60 and 90 um). Eleven out of twelve targets show a peak of excess (above photosphere) far infrared emission at the location of the star, implying that the dust particles are truly associated with stars. To estimate the size of the excess emission source, the flux ratio of center to boundary pixels of the 3x3 array was examined. The radius of the dust emission is found to be ~3000 to ~10000 AU for a thin shell distribution, and ~5000 to ~25000 AU for a uniform distribution. We consider three models for the origin of the dust: disintegration of comets, sporadic dust ejection from the star, and emission from nearby interstellar cirrus. The data seem to rule out the first model (as far as the "Kuiper--belt" like particles are assumed to be large blackbody grains), but do not enable us to choose between the other two models.

arXiv commentTo appear in the ApJ, scheduled for the March 20, 2001 issue

Cited by in corpus (9)

• The age dependence of the Vega phenomenon: Observations
• Post-main sequence evolution of A star debris discs
• Spitzer 24 micron Survey of Debris Disks in the Pleiades
• Discovery of Reflection Nebulosity Around Five Vega-like Stars
• Spatially Resolved Images of Dust Belt(s) Around the Planet-hosting Subgiant Kappa CrB
• A Flared, Orbiting, Dusty Disk Around HD 233517
• Other Kuiper Belts
• Polycyclic Aromatic Hydrocarbons Orbiting HD 233517, an Evolved Oxygen-Rich Red Giant
• Li-rich K giants, dust excess, and binarity