Astro-2 Public Affairs Status Report #30 6:00 p.m. CST (14/17:22 MET), March 16, 1995 Spacelab Mission Operations Control Marshall Space Flight Center Huntsville, Ala. STS-67 crew members continued to put the Shuttle Endeavour and the Astro-2 telescopes through a stately waltz of maneuvers and observations, as they finished up a number of the mission's precedent-setting ultraviolet astronomy investigations. The Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE) team wrapped up two studies about how stars put material back into the interstellar medium, which in turn can build new stars. They viewed the star Xi Persei to complete their study of Oe/Be stars. These rapidly spinning, hot massive stars are found primarily in the arms of spiral galaxies. The WUPPE observations should help determine the shapes of the gas shells spun off or otherwise ejected by the stars. WUPPE also observed Vela X-1, in the instrumentŐs final polarization measurement of an X-ray binary star. It is believed that such systems are made up of a neutron star, which may be a pulsar, in an eccentric orbit around a more normal primary star. At the closest approach, the neutron star gravitationally strips material off the primary star. The material then flows along the neutron star's magnetic field and crashes onto the surface to produce a sudden burst of X-rays. However, much of the stripped material forms a disk around the neutron star instead of settling onto star's surface. The WUPPE measurements will help define the geometry and the extent of this circumstellar disk, as well as details about the densities and temperatures within the shells. Observations of the stars HD 147888 and Omicron Scorpii were for WUPPE's study of the dust between stars in our galaxy. The WUPPE team will use their findings about variations in the distribution, shapes and composition of this dust to understand more about this raw material for star formation. A better knowledge of how the dust polarizes light also will allow astronomers to subtract the interference of intervening dust from star observations. The Hopkins Ultraviolet Telescope (HUT) team selected two white dwarf stars for today's observation block. Today's study of the white dwarf RE 1738 completed Guest Investigator Dr. David Finley's data set for his calibration of temperature scales for these small but massive remains of dying stars. The mission's fourth observation of 1424+535 added more information about a transitory evolutionary stage of white dwarf stars with powerful magnetic fields. These pulsating white dwarfs undergo periodic changes in brightness, but the causes of the pulsations and the chemical composition of the stars' visible surfaces is not well understood. Guest Investigator Dr. Brian Espey got one last look at a symbiotic star system with a joint HUT and WUPPE observation of AG Draconis. The study essentially aims to "take the temperature" of the hot, sub-dwarf component of this two-star group, whose co-orbiting members vary widely in temperature. Espey also hopes to determine the size and density of the cool material that lies in the atmosphere of the red giant component. The HUT team made their last quasar observation when they viewed PG 1351, one that is relatively closer than those HUT is using in its search for intergalactic helium. HUT is examining "nearby" quasars to understand better the processes taking place within these extremely energetic objects. Team members will also search their data to test the widely accepted theory that quasars are powered by supermassive black holes. The majority of targets chosen by the Ultraviolet Imaging Telescope (UIT) team today were galaxies. They selected two active galaxies thought to have black holes at their centers. NGC 1566 is a faint, nearby Seyfert I type galaxy, the type which radiates most strongly in ultraviolet and X-ray wavelengths and has high gas velocities and spectra resembling a quasar. NGC 3226-7 is a Seyfert II galaxy, with a lower gas velocity than the Type 1 Seyferts. UIT astronomers are studying both types to learn more about how energy is transferred between the galaxies' centers and surrounding regions. UIT photographed two final spiral galaxies, NGC 5236 and M 63, for the atlas of these stunning celestial objects being assembled during this mission -- most of which had never before been photographed in the ultraviolet. Astronomers can use the shapes of nearby spiral galaxies revealed in ultraviolet light to classify more distant galaxies photographed in visible light by the Hubble Space Telescope. The radiation from those far-away galaxies was actually emitted in ultraviolet wavelengths, then stretched by the expansion of the universe into the visible band by the time it reached Earth's vicinity. UIT concluded its Astro-2 album of galaxies by imaging a section of one of our nearest neighboring galaxies, the Small Magellanic Cloud. The UIT team led the Astro observatory in viewing NGC 362, the last globular cluster observation of the flight. The camera's ultraviolet images pick out hot stars from the clutter of cooler objects. UIT also imaged the Thumbprint Nebula in the mission's only look at that particular dark cloud of gas and dust in interstellar space. This morning's planned observation of Earth's moon was unsuccessful, due to problems with the tricky maneuver of tracking such a nearby object with a system designed for stellar pointing. However, the Astro-2 instruments successfully viewed the moon twice before in the mission. For the final set of Astro-2 observations tonight, the WUPPE team has added the brightest known Wolf-Rayet star, Gamma 2 Velorum, to the observation menu. The Astro-2 telescopes also will study reflection nebula Eta Carinae, cataclysmic variable EM Cygni, starburst galaxy Markarian 66 and the Cygnus Loop supernova remnant. The STS-67 crew will stow the Instrument Pointing System at around 11 p.m. CST, and the three telescopes then will be deactivated by ground commands. A wrap-up report summarizing Astro-2 mission highlights will be released at around 9:30 tonight. To follow the mission in progress, visit Astro-2's home page on the Internet World Wide Web: URL "http://astro-2.msfc.nasa.gov"