Gas absorption detected from the edge-on debris disk surrounding HD 32297.
Abstract (from CDS):
Near-infrared and optical images of HD 32297 indicate that it has an edge-on debris disk, similar to β Pic. I present high-resolution optical spectra of the Na I doublet toward HD 32297 and stars in close angular proximity. A circumstellar absorption component is clearly observed toward HD 32297 at the stellar radial velocity, which is not observed toward any of its neighbors, including the nearest only 0.9' away. An interstellar component is detected in all stars >90 pc, including HD 32297, likely due to the interstellar material at the boundary of the Local Bubble. Radial velocity measurements of the nearest neighbors, BD +07 777s and BD +07 778, indicate that they are unlikely to be physically associated with HD 32297. The measured circumstellar column density around HD 32997, logN_NaI_∼11.4, is the strongest Na I absorption measured toward any nearby main-sequence debris disk, even the prototypical edge-on debris disk β Pic. Assuming that the morphology and abundances of the gas component around HD 32297 are similar to β Pic, I estimate an upper limit to the gas mass in the circumstellar disk surrounding HD 32297 of ∼0.3 M⊕.