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Session 41 - T Tauri Stars & Protostellar Regions.
Display session, Wednesday, June 11
South Main Hall,
We present an atlas of IUE low-dispersion short-wavelength spectra of pre-main sequence stars. These spectra are co-additions from all useful images which have been reprocessed with NEWSIPS. Compared to the earlier processing of these spectra with IUESIPS, each spectrum has significantly higher signal/noise and most blemishes and cosmic ray hits are now removed. Since most of the fixed pattern noise is removed by NEWSIPS, the spectra can be coadded with considerable increase in signal/noise.
Using the available lists of pre-main sequence stars (e.g., SIMBAD, Herbig and Bell catalog, Thé et al. catalog, Walter Sco-Cen catalog, and Jones and Walker catalog), we have identified 128 objects observed by IUE, including 50 T Tauri stars and 78 Herbig Ae/Be stars. 663 usable spectra are available from the IUE Final Archive for these targets, and our atlas consists of coadded spectra for each star based on up to 94 individual spectra (AB Aur). The stars cover the spectral type range from B0 to M3. This atlas is essentially a complete sample of all PMS stars that were observed by IUE in the far-UV (1175 -- 2000 ÅP>Our objective is to obtain the highest quality spectra of these stars and to extract fluxes of the broad range of emission features produced in the atmospheres and disks of different kinds of PMS stars. These spectral features consist of emission lines formed at temperatures as high as 150,000 K (N V), molecular features (e.g., H_2), and absorption lines formed in the hotter stars. Our identification of emission lines and blends is aided by comparison with an archival GHRS spectrum of T Tauri. We tabulate line and continuum fluxes and compare these UV properties (in particular, H_2) with stellar, accretion, and wind properties. These mean spectra will also serve as fiducials for future studies of time variability.
This work is supported by NASA grants to the University of Colorado.
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