This is a resubmission. Bret caught the fact that when APT added the proposal ID the abstract was then too long. I've now shortened the abstract. THANKS FOR CATCHING THIS!!! ----- Submission 1 (Thu Jan 23 14:12:57 MST 2003) ----- Assigned ID: 487 Successfully submitted: Thu Jan 23 14:14:54 MST 2003 ----- Submission 2 (Thu Jan 23 16:19:47 MST 2003) ----- Successfully submitted: Thu Jan 23 16:20:03 MST 2003 The Physical Parameters and Stellar Winds of Hot, Massive Stars at High Metallicity: O-stars in the Andromeda Galaxy Stellar winds are a ubiquitous phenomenon among high luminosity hot stars, and the resulting mass-loss has a significant effect on their evolution, as a very massive star might lose half its mass during its main-sequence life. There has been significant progress in understanding the physics of radiatively-driven winds, and simple theoretical parameterizations of mass-loss with stellar properties, such as luminosity, effective temperature, and surface gravity, have been developed. These provide good agreement with the observed mass-loss rates for Galactic stars. Scaling these mass-loss rates to other environments, where the metallicity Z is different than solar, requires a power-law in Z, but various studies have found values for this exponent ranging from 0.5 to 1.0. Here we are hampered by the scant range in metallicities covered by the observational database, which extends only from one-third solar (SMC) to solar (Milky Way). We are proposing to extend this work to a sample of four O8-O8.5If stars in the Andromeda Galaxy (M31), where the metallicity measured from HII regions is about twice solar. Significant ground-based and HST time has gone into setting the stage for this, but it is only in the last few years that good throughput in the FUV (thanks to STIS/MAMA) and large aperture optical telescopes have permitted the gathering of data of the quality needed for a quantitative spectroscopic analysis similar to what we can do for low-metallicity Magellanic Cloud stars. We have obtained most of the optical spectra we need with the newly reburbished 6.5-m MMT and are now requesting the FUV spectra that only HST/STIS can provide. The resulting analysis will not only yield mass-loss rates but also the physical parameters (Teff, log g, luminosity, radius, mass, and metallicity), which can then be compared to their lower-metallicity counterparts. Parallel imaging with WFPC2 and ACS will provide data useful to ourselves and others for the study of the resolved stellar population of the Local Group galaxy most like our own.
We have four primary targets: M31OB78-231, M31OB78-387, M31OB10-150, and M31OB48-444. We require 10 orbits of STIS/FUV-MAMA ACCUM data on each of our targets; in order to facilitate schedule, we will therefore use two 5-orbit visits per target. During each of the 5-orbit visits we will also make coordinate parallel observations using BOTH the ACS AND WFPC2 simultaneously. HOT STARS 12 false 1 false false false SUPPORTED EXT-STAR A0-A3 III-I Identification and photometry from Massey et al 1986 AJ 92, 1303 B-V=0.00 U-B=-0.62 ob78-163 J2000 EXT-STAR SUPERGIANT O Identification and photometry from Massey et al 1986 AJ 92 1303 B-V--0.19 U-B=-1.09 EXT-STAR A0-A3 III-I photometry and identification from Massey et al 1986 AJ 92, 1303 B-V=0.01 U-B=-0.47 ob78-453 J2000 EXT-STAR A0-A3 III-I SUPERGIANT O Photometry and identification from Massey et al 1986 AJ 92, 1303 B-V=-0.15 U-B=-1.04 EXT-STAR A0-A3 III-I From Massey et al 1986 AJ 93, 1303 B-V=0.49 U-B=-0.14 ob48-471 J2000 EXT-STAR SUPERGIANT O Identification and photometry from Massey et al 1986 AJ 93, 1303 B-V=-0.02 U-B=-1.04 EXT-STAR SUPERGIANT O Identification and photometry from Massey et al 1986 AJ 93, 1303 B-V=-0.04 U-B==-0.96 J2000 00 40 29.69 +40 44 29.83 J2000 STIS/FUV-MAMA ACCUM Spectroscopic No STIS/FUV-MAMA ACCUM 00 40 31.69 +40 45 43.12 J2000 STIS/FUV-MAMA ACCUM Spectroscopic No STIS/FUV-MAMA ACCUM 00 44 12.97 +41 33 28.9 J2000 STIS/FUV-MAMA ACCUM Spectroscopic No STIS/FUV-MAMA ACCUM 00 45 15.26 +41 37 47.91 J2000 STIS/FUV-MAMA ACCUM Spectroscopic No STIS/FUV-MAMA ACCUM 00 40 29.69 +40 44 29.8 J2000 WFPC2 IMAGE Imaging No WFPC2 IMAGE 00 40 29.69 +40 44 29.8 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 40 29.69 +40 44 29.8 J2000 WFPC2 IMAGE Imaging No WFPC2 IMAGE 00 40 29.69 +40 44 29.8 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 40 31.69 +40 45 43.12 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 40 31.69 +40 45 42.12 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 40 31.69 +40 45 43.12 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 40 31.69 +40 45 42.12 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 44 12.97 +41 33 28.9 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 44 12.97 +41 33 28.9 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 44 12.97 +41 33 28.9 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 44 12.97 +41 33 28.9 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 45 15.26 +41 37 47.91 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 45 15.26 +41 37 47.91 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 45 15.26 +41 37 47.91 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM 00 45 15.26 +41 37 47.91 J2000 ACS/WFC ACCUM Imaging No ACS/WFC ACCUM /home/massey/cycle12/OP-cache/m31spect-v01.xml (Tic-Visit :proposal-id 9794 :visit-id "01" :proposal-version -1 :trans-version "20030408" :date "18-Apr-2003 20:18:52.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 87504 :tdrss-contact-duration 0 ) (Tic-Obset :proposal-id 9794 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 9794 :visit-id "01" :orbit-number 1 :pcs-time 365 :si-vis-utilization 2903 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3272 :pcs-gap 0 ) false /home/massey/cycle12/OP-cache/m31spect-v01.xml