2006/01/20 by C. A. Beichman, A. Tanner, G. Bryden +6 · 3 citations
Physics and Astronomy · #Asteroid #Asteroid belt #Astro and Planetary Science #Astronomy and Astrophysical Research #Brightness #Photometry (optics) #Population #Spectral line #Stars #Stellar, planetary, and galactic studies #Zodiacal light #astro-ph
paper · pdf · doi:10.1086/499424
published as Astrophys.J. 639 (2006) 1166-1176
arxiv created 2006/01/20 · openalex publication_date 2006/03/06 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.