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Preprint 09a/10

Asymmetric Line Profiles in Spectra of Gaseous Metal Disks Around Single White Dwarfs

Stephan Hartmann (1), Thorsten Nagel (1), Thomas Rauch (1), and Klaus Werner (1)

(1) Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, D-72076 Tübingen, Germany

To be published in: Proceedings of the 17th European White Dwarf Workshop, AIP Conference Series

Abstract. Around several single DAZ and DBZ white dwarfs metal-rich disks have been observed, which are mostly believed to originate from disruption of smaller rocky planetesimals. In some cases the material does not (only) form a dusty but gaseous disk. In the case of SDSS J122859.93+104032.9 the double peaked infrared Ca II triplet λλ 8498, 8542, 8662 Å, one of only two emission features of the spectra, exhibits a strong red/violet asymmetry. Assuming a composition similar to a chondrite-like asteroid, being the most prominent type in our own solar system, we calculated the spectrum and vertical structure of the disk using the Tübingen non-LTE accretion disk code AcDc. Modified to simulate different non axis-symmetrical disk geometries, the first preliminary results are in good agreement with the observed asymmetric line profile.
 
Key words: stars: individual (SDSS J122859.93+104032.9), white dwarfs, circumstellar matter, planetary systems

Preprint (1,03 Mb PDF file including figures)

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