Discovery of an Extended Debris Disk around the F2 V Star HD 15745

Abstract

Using the Advanced Camera for Surveys aboard the Hubble Space Telescope, we have discovered dust-scattered light from the debris disk surrounding the F2 V star HD 15745. The circumstellar disk is detected between 2.0" and 7.5" radius, corresponding to 128-480 AU radius. The circumstellar disk morphology is asymmetric about the star, resembling a fan, and consistent with forward scattering grains in an optically thin disk with an inclination of ~67° to our line of sight. The spectral energy distribution and scattered light morphology can be approximated with a model disk composed of silicate grains between 60 and 450 AU radius, with a total dust mass of 10^-7 M_solar (0.03 M_⊕), representing a narrow grain size distribution (1-10 μm). Galactic space motions are similar to the Castor moving group, with an age of ~10⁸ yr, although future work is required to determine the age of HD 15745 using other indicators.