IRS spectra of solar-type stars: A search for asteroid belt analogs

C. A. Beichman, A. Tanner, G. Bryden, K. R. Stapelfeldt, M. W. Werner, G. H. Rieke, D. E. Trilling, S. Lawler, T. N. Gautier

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


We report the results of a spectroscopic search for debris disks surrounding 41 nearby solar-type stars, including eight planet-bearing stars, using the Infrared Spectrometer (IRS) on the Spitzer Space Telescope. With the accurate relative photometry of the IRS between 7 and 34 μm we are able to look for excesses as small as ∼2% of photospheric levels, with particular sensitivity to weak spectral features. For stars with no excess, the 3 σ upper limit in a band at 30-34 μm corresponds to ∼75 times the brightness of our zodiacal dust cloud. Comparable limits at 8.5-13 μm correspond to ∼1400 times the brightness of our zodiacal dust cloud. These limits correspond to material located within the < 1 to ∼5 AU region that, in our solar system, originates predominantly from debris associated with the asteroid belt. We find excess emission longward of ∼25 μm from five stars, of which four also show excess emission at 70 μm. This emitting dust must be located in a region starting around 5-10 AU. One star has 70 μm emission but no IRS excess. In this case, the emitting region must begin outside 10 AU; this star has a known radial velocity planet. Only two stars of the five show emission shortward of 25 μm, where spectral features reveal the presence of a population of small, hot dust grains emitting in the 7-20 μm band. One of these stars, HD 72905, is quite young (300 Myr), while the other, HD 69830, is older than 2 Gyr. The data presented here strengthen the results of previous studies to show that excesses at 25 μm and shorter are rare: only 1 out of 40 stars older than 1 Gyr or ∼2.5% shows an excess. Asteroid belts 10-30 times more massive than our own appear are rare among mature, solar-type stars.

Original languageEnglish (US)
Pages (from-to)1166-1176
Number of pages11
JournalAstrophysical Journal
Issue number2 I
StatePublished - Mar 10 2006


  • Circumstellar matter
  • Comets: general
  • Kuiper Belt
  • Minor planets, asteroids
  • Planetary systems

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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