Astro-2 Public Affairs Status Report #8	
6:00 p.m. CST (3/17:22 MET), March 5, 1995	
Spacelab Mission Operations Control	
Marshall Space Flight Center	
Huntsville, Ala.

     The Astro-2 telescopes continued their exploration of the
unknown today, getting unique ultraviolet observations of a number of
celestial objects.

     This morning, Payload Commander Tammy Jernigan and Payload
Specialist Sam Durrance worked together to train the Astro instruments
on objects selected by the Hopkins Ultraviolet Telescope (HUT) team.

     Both the Hopkins telescope and the Wisconsin Ultraviolet
Photo- Polarimeter Experiment (WUPPE) examined two Seyfert galaxies,
Markarian 279 and Fairall 9, in a study that could provide insights
into some of the most powerful events in the universe.  Named for
Vanderbilt University astronomer Carl Seyfert, who identified this
type of galaxy in 1943, Seyferts have extremely bright, compact cores
containing clouds of gas moving at thousands of miles per second.
Astronomers theorize that supermassive black holes would be the only
source capable of generating the immense power given off by these
objects.

     The HUT team also practiced acquiring quasar Q 1542+54 to
refine procedures for locating it efficiently in future observations.
Their success gives them an additional illumination source to use in
their search for intergalactic helium.  Yesterday, they successfully
locked onto the quasar 1700+64, which will likely remain their primary
target for the study.

     Several observations today examined the dust and gas from which
stars form. HUT selected a reflection nebula and the star which
illuminates it.  The star, AE-Aurigae, is a very hot, massive blue
star with surface temperatures from 50,000 to 70,000 degrees
Fahrenheit (28,000 to 40,000 Kelvin).  Light from the star illuminates
a cloud of dust surrounding it, creating a bright, colorful nebula.
Observation by the Astro telescopes may help determine the composition
of the dust and the sizes and shapes of the grains.

     The first observation today with WUPPE as the lead instrument was
HD 50138, viewed after Mission Specialist John Grunsfeld and Payload
Specialist Ron Parise took over science crew duties.  This
pre-main-sequence star is thought to be a young object, several times
more massive than our sun, that has just formed out of the
interstellar gas and dust.  Polarization measurements should help show
the shape of the nebula which surrounds the star and indicate where it
is coming from.  The study should help astronomers learn more about
the ways in which young stars form and how their birth clouds
eventually disperse.

     The WUPPE team also observed the star HD 197770, an interstellar
polarization probe.  The star serves much like a flashlight,
illuminating the vast and normally invisible clouds of dust and gas in
the space between stars.  The materials in these swirling clouds are,
in essence, the stuff of past and future stars.  Over eons, as stars
grow old, they kick out vast amounts of very hot material -- mostly
gas and dust -- into space.  These materials form into clouds, and
over many thousands of years the clouds collapse and form new stars.
By determining how much the ultraviolet light passing through the
clouds is polarized, or vibrating in a preferred direction rather than
randomly, WUPPE can provide further clues as to the nature of this
interstellar dust.

     Phi Persei, a hot, rapidly spinning star, was another subject of
study for WUPPE.  The star exhibits an unusual ultraviolet spectrum
that may be caused by a shell of gas around the star, possibly the
remains of a layer that has been spun off the star by its rapid
rotation.  This shell is thought to be in the form of a disk around
the equator of the star, and the scattering of starlight by the disk
polarizes the light.

     Celestial objects chosen for observation by the Ultraviolet
Imaging Telescope (UIT) included M31, the famous Andromeda galaxy in
our "local group," the cluster of galaxies which includes our own
Milky Way.  UIT researchers are conducting ultraviolet studies of the
structure of local group galaxies.  They will also examine the
photographs to study the physics of star formation contained in these
galaxies.

     The UIT team also selected various kinds of open and globular
star clusters, groups of stars formed from the same basic material at
the same time.  By comparing clusters of different ages and by looking
at different types of stars of the same age, astronomers can learn a
great deal about how each type of star changes in its lifetime.

     Tonight, the Astro instruments will view spiral, radio,
elliptical and rapid- star-formation galaxies, as well as two types of
binary star systems and some individual stars.  The Hopkins telescope
also will continue its search for intergalactic helium.

     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"