Poster Abstracts

Name/Affiliation:  K.G. Carpenter and T.R. Ayres for the ASTRAL Science Team (NASA's GSFC)

Title:  The HST Treasury "Advanced Spectral Library (ASTRAL)" Programs

Over the past three years, two of the largest-ever HST stellar spectroscopic Guest Observer programs have been undertaken. The "Advanced Spectral Library (ASTRAL)" Project (PI = T. Ayres) consists of two Treasury Programs, the first in Cycle 18 on "Cool Stars" (GO-12278) and the second in the current Cycle 21 on "Hot Stars" (GO-13346). These programs are designed to collect a definitive set of representative, high-resolution (R~30,000-100,000), high signal/noise (S/N>100) spectra, with full UV coverage (~1200 - 3000 ) of prototypical stars across the HR diagram, utilizing the high-performance Space Telescope Imaging Spectrograph (STIS). ASTRAL/Cool Stars obtained spectra of 8 F-M evolved late-type stars, including iconic objects like Betelgeuse and Procyon. ASTRAL/Hot Stars is in the process of observing 21 early-type stars, which span a broad range of spectral types between early-O and early-A, both main sequence and evolved stars, fast and slow rotators, as well as chemically peculiar and magnetic objects. The targets include equally iconic Sirius, Vega, and the classical wind source Zeta Puppis. All of these extremely high-quality STIS UV echelle spectra will be available from the HST archive and, in post-processed and merged form, at These data will enable investigations of a broad range of problems -- stellar, interstellar, and beyond -- for many years into the future. Here we describe the details of the observing programs and the spectra now available for community use; and then present some illustrative examples of the on-going scientific analyses, including a study of the outer atmospheres and winds of the two evolved M stars in the sample, the M3.4 giant Gamma Cru and the M2Iab supergiant Alpha Ori and a first look at a "high definition" UV spectrum of the magnetic chemically peculiar "Ap" star HR 465.