Our Sun is surrounded by a disk of warm (1150 K) “zo- diacal” dust that radiates most of its thermal energy at 10–30 mm. This dust is produced largely in the inner part of the solar system by collisions in the asteroid belt (Dermott et al. 1992) and cometary outgassing (Liou & Zook 1996). Zodiacal dust is interesting as a general feature of planetary systems, and as an indicator of the presence of larger bodies that supply it; dust orbiting a few AU from
The authors observed six nearby main‑sequence stars with the Long Wavelength Spectrometer on the W. M. Keck telescope at 11.6 µm, employing speckle analysis to achieve diffraction‑limited resolution. By comparing calibrated power spectra of target stars with those of calibrator stars, they searched for resolved dust emission beyond the stellar point‑spread function.
Modeling based on COBE/DIRBE data allowed the team to translate the non‑detections into upper limits on dust density. The most stringent limit was for Altair, where a solar‑type dust disk a few times 10 × denser than the solar zodiacal cloud was ruled out.
Altair’s observations ruled out a solar‑type dust disk a few times 10 × denser than the solar zodiacal cloud.
The observations were made with the W. M. Keck telescope.