Spectroscopic Update on the ``Moon Star''
First Author:
Nadya Gorlova
Email: ngorlova AT astro.ufl.edu
University of Florida
211 Bryant Space Science Center
Gainesville, FL, 32611
Coauthors:
Kovtyukh, Valery, Odessa Observatory, Ukraine
Rieke, George, University of Arizona
Lobel, Alex, Royal Observatory of Belgium
Su, Kate, University of Arizona
Muzerolle, James, University of Arizona
Abstract
To probe whether they represented huge collisions like the one that formed our Moon, we obtained VLT echelle spectra of two stars with strong IR excesses in the 40 Myr-old cluster NGC 2547 (Gorlova et al. ApJ 2007). The following parameters were examined to assess membership in the cluster: radial velocity, chromospheric activity, lithium, surface gravity, metallicity, and the spectroscopic parallax. ID9 and one comparison star appear to be old background G-K giants. ID9 could be an RV Tau system with a circumbinary disk mimicking that of classical TTau stars. On the other hand ID8 (the ``Moon star'') is confirmed to be a member of roughly solar-type, reinforcing the interpretation of its optically-thin disk as a result of a protoplanetary collision, similar to one that created Moon in the Solar system.
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