Infrared Emission by Dust Around λ Bootis Stars: Debris Disks or Thermally Emitting Nebulae?

J. R. Martinez-Galarza*, I. Kamp, K. Y. L. Su, A. Gaspar, G. Rieke, E. E. Mamajek

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

22 Citations (Scopus)

Abstract

We present a model that describes stellar infrared excesses due to heating of the interstellar (IS) dust by a hot star passing through a diffuse IS cloud. This model is applied to six. Bootis stars with infrared excesses. Plausible values for the IS medium (ISM) density and relative velocity between the cloud and the star yield fits to the excess emission. This result is consistent with the diffusion/accretion hypothesis that. Bootis stars (A- to F-type stars with large underabundances of Fe-peak elements) owe their characteristics to interactions with the ISM. This proposal invokes radiation pressure from the star to repel the IS dust and excavate a paraboloidal dust cavity in the IS cloud, while the metal-poor gas is accreted onto the stellar photosphere. However, the measurements of the infrared excesses can also be fit by planetary debris disk models. A more detailed consideration of the conditions to produce. Bootis characteristics indicates that the majority of infrared-excess stars within the Local Bubble probably have debris disks. Nevertheless, more distant stars may often have excesses due to heating of IS material such as in our model.

Original languageEnglish
Pages (from-to)165-173
Number of pages9
JournalAstrophysical Journal
Volume694
Issue number1
DOIs
Publication statusPublished - 20-Mar-2009

Keywords

  • circumstellar matter
  • infrared: ISM
  • ISM: clouds
  • stars: chemically peculiar
  • MULTIBAND IMAGING PHOTOMETER
  • DIFFUSE INTERSTELLAR-MEDIUM
  • ABSOLUTE CALIBRATION
  • PARTICLE-TRANSPORT
  • SOLAR-SYSTEM
  • HI CLOUDS
  • MASS-LOSS
  • A-STARS
  • ACCRETION
  • SPITZER

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