The absence of cold dust around warm debris disk star HD15407A

Abstract

We report Herschel and AKARI photometric observations at far-infrared (FIR) wavelengths of the debris disk around the F3V star HD15407A, in which the presence of an extremely large amount of warm dust (∼500-600K) has been suggested by mid-infrared (MIR) photometry and spectroscopy. The observed flux densities of the debris disk at 60-160 μm are clearly above the photospheric level of the star, suggesting excess emission at FIR as well as at MIR wavelengths previously reported. The observed FIR excess emission is consistent with the continuum level extrapolated from the MIR excess, suggesting that it originates in the inner warm debris dust and cold dust (∼50-130K) is absent in the outer region of the disk. The absence of cold dust does not support a late-heavy-bombardment-like event as the origin of the large amount of warm debris dust around HD15047A. © 2012. The American Astronomical Society. All rights reserved.