STS-67 Day 12 Highlights
Back to STS-67 Flight Day 11 Highlights:
- On Tuesday, March 14, 1995 at 6 a.m. CST, STS-67 Payload Status Report # 25
reports: (12/5:22 MET) The Ultraviolet Imaging Telescope
(UIT) imaged NGC 2300, a cluster of galaxies that emits large
quantities of X-rays. The study of clusters can provide a wealth of
information to astronomers. Astro-2 data may provide UIT scientists
with a better understanding of the relationship between galaxies in a
cluster, the relationships between different levels of clusters and
star formation in clusters of galaxies.
- UIT also imaged a globular cluster, NGC 5272, that contains
relatively old stars. The low metal content in this cluster of stars
indicates they were formed early in the life of the Milky Way galaxy.
The telescope, image intensifiers and cameras of the UIT instrument
are helping astronomers search for hot accreting binaries, hot white
dwarfs, planetary nebulae and objects associated with X-ray sources in
- The study of young stellar populations in galaxies continued when
UIT was pointed at a galaxy field in the spiral galaxy Andromeda.
Approximately half of UIT's Astro-2 science program is devoted to the
study of star-forming galaxies such as this one. A unique feature of
UIT is the identification of thousands of individual hot stars in
other galaxies that shine brightly in the ultraviolet. These hot
stars may be observed later by the Hubble Space Telescope. UIT imaged
another spiral galaxy, NGC 925, to provide images for Guest
Investigator Dr. Wendy Freedman's atlas of spiral galaxies.
- UIT and the Wisconsin Ultraviolet Photo-Polarimeter Experiment
(WUPPE) were pointed at the moon again last night. UIT imaged the
moon to help astronomers, such as Guest Investigator Dr. Randy
Gladstone, learn more about the surface properties of the moon.
Scientists will develop and analyze the UIT film after Endeavour
returns to Earth to understand future ultraviolet images of asteroids
and other planetary satellites. WUPPE scientists observed the moon,
looking at the reflection of ultraviolet light for distinctive
differences in the maria (dark areas of the lunar surface) and
highlands (brighter surface features of the moon).
- The Hopkins Ultraviolet Telescope (HUT) was used to observe a
radio- loud quasar in the far- and extreme-ultraviolet wavelengths.
HUT Principal Investigator Dr. Arthur Davidsen will analyze the
Astro-2 data of this quasi- stellar object (located in the
constellation Eridanus) to understand more about the shape of its
ultraviolet spectrum. Davidsen is looking for the region of the
ultraviolet spectrum where the hydrogen becomes opaque to radiation.
He will then compare what he learns from these observations with what
astronomers already know about the disk-shaped structure of stellar
matter surrounding a black hole, testing the theory that quasars are
powered by supermassive black holes.
- Hopkins scientists also observed the Seyfert galaxy NGC 5548 with
HUT last night. The ultraviolet absorption lines in the HUT spectrum
will be used in conjunction with earlier X-ray observations to
determine the physical conditions in the hot absorbing gas. The
absorbing gas in this Seyfert 1 galaxy may be the "reflecting medium"
that produces the polarized reflection spectrum seen in Seyfert 2
galaxies such as NGC 1068.
- Two elliptical galaxies were also observed by HUT last night.
Elliptical galaxies, which are spherical with no clearly defined
internal structure, contain older, more evolved stars. Galaxy M87,
the central galaxy in the Virgo cluster, shows signs that star
formation may be occurring even though elliptical galaxies do not have
enough stellar matter for new star formation. Another galaxy, known
as M60, is being observed during this mission because it has a very
high "ultraviolet upturn" an excess of ultraviolet output for an
old star population. The UIT team is also very interested in these
targets UIT collected ultraviolet images of both galaxies in
support of several science programs.
- The WUPPE telescope was calibrated during an observation of Beta-
Ursa Majoris, a star that remains relatively constant in luminosity.
The surrounding area of this star is virtually dust free, giving WUPPE
scientists a good, clear target to determine if there have been any
changes in the performance of their telescope during this mission.
- HUT and WUPPE scientists used their ultraviolet telescopes to study
a binary star system known as a magnetic cataclysmic variable. This
two-star system, called AM Herculis, has a white dwarf star that pulls
material away from its companion red star. A strong magnetic field on
the white dwarf causes stellar material from the red star to
accumulate on the white star's poles. Information about the dynamics
of mass transfer in a binary star system is important because
accretion, or the accumulation of gas, is essential to many
astrophysical situations, such as star and planetary formation.
- On Tuesday, March 14, 1995 at 8 a.m. CST, STS-67 MCC Status Report
#24 reports: Endeavour's crew was notified of the Mir-18 launch
shortly after the Soyuz capsule reached orbit. STS-67 Commander Steve
Oswald responded, "Okay, great news, thank you very much....Bet you
Normie's glad to be there." Oswald and Thagard flew together on
Discovery's STS-42 mission in January 1992.
- On Tuesday, March 14, 1995 at 5 p.m. CST, STS-67 MCC Status Report # 25
reports: Before turning in for an eight-hour sleep period, the
Blue team astronauts, Wendy Lawrence, Tammy Jernigan and Sam Durrance,
joined their colleagues in the traditional in-flight Crew News
Conference, answering questions from correspondents on everything from
astronomical research to the symbolism of the launching of
U.S. astronaut Norm Thagard on a Russian rocket this morning to begin
an historic three-month stay on the Mir Space Station.
- Earlier today, NASA's Mission Management Team decided NOT to extend
Endeavour's flight beyond Friday's planned landing at the Kennedy
Space Center. Citing the wealth of scientific data already acquired by
the Shuttle's telescopes and the conservative approach being taken in
slowly building up the length of time for orbiting crews, Mission
Operations Representative Jeff Bantle said the decision to end
Endeavour's journey on time was made after weighing numerous factors
regarding a mission extension, both pro and con.
- On Tuesday, March 14, 1995 at 6 p.m. CST, STS-67 Payload Status Report # 26
reports: CST (12/17:22 MET) The majority of today's Astro-2
observations were of objects in the Large and Small Magellanic Clouds.
These irregular galaxies, in the southern hemisphere sky, are
satellites of our Milky Way galaxy. They are gravitationally bound
with some 20 others that make up our "local group" of galaxies.
- The Ultraviolet Imaging Telescope made the mission's first
photographs of Supernova 1987A. The February 1987 stellar explosion,
in the Large Magellanic Cloud, was the first supernova explosion
visible to the naked eye since 1604 A.D., six years before the first
telescope was used to view the heavens. The supernova reached its
brightest visible radiation level in May 1987, but scientists believe
an intense flash of ultraviolet light occurred almost at the moment of
the explosion, when the outer layers of the supernova lifted away.
UIT is attempting to photograph the light "echo," or reflection of
this maximum ultraviolet output, as it bounces off sheets of dust in
space. UIT's Astro 1 photographs of Supernova 1987A indicate the echo
is extremely faint, so UIT is making a number of long exposures to
capture it. "If we see the same phenomenon in several exposures, we
can not only add them together to improve the quality of our
observations; the repeated evidence assures us that what we are seeing
is real," said UIT team member Dr. Steve Maran.
- An observation of N 79 looked at young star formation in a Large
Magellanic Cloud star grouping called an "OB Association." Unlike
other types of star clusters, there is insufficient gravitational
attraction to hold these groups of very young, hot O and B stars
together. Though formed at the same time, the stars are rapidly
- Other targets in UIT's eight-observation time block included two
Large Magellanic Cloud open star clusters which are surrounded by
emission rings. N 51, in the southern constellation Dorado, is an
unusual nebula which appears to be a bubble blown in the interstellar
gas by wind from a very massive hot star. The imaging telescope made
limited observations of the area during Astro-1, and the science team
hopes to collect more extensive data on this flight. N 70, in the
southern constellation Hydra, is a region of space where the gas has
been ionized. The UIT team will compare images made at two different
wavelengths to help determine what caused the ionization.
- UIT also photographed the bar structure of the Large Magellanic
Cloud, an elongated linear accumulation of stars in the galaxy, as
part of its study of young star populations. Dr. John Raymond, of the
Smithsonian Institution's Astrophysical Observatory, added to his
study of interstellar shock waves with an observation of LMC 519, an
old supernova remnant also in the Large Magellanic Cloud. Dr. Nolan
R. Walborn got another observation of a hot O star in the open star
cluster NGC 346, for his study of the strong stellar winds produced by
these stars in the Large and Small Magellanic Clouds.
- This evening, Dr. Geoffrey Clayton began another block of
observations for his study of interstellar dust in the Large
Magellanic Cloud. Wisconsin Ultraviolet Photo-Polarimeter Experiment
(WUPPE) Principal Investigator Dr. Arthur Code is researching the
sizes and chemical compositions of dust grains in the Milky Way's
interstellar medium. Clayton is extending the sample to the nearby
Large Magellanic Cloud, where interstellar chemical abundances are
known to be quite different from those in our own galaxy.
- All three telescopes participated in the third Astro-2 observation
of 47 Tucanae, a metal-rich globular cluster in the southern Milky
Way. The Astro telescopes also viewed Centaurus A, the nearest active
galaxy to our own and one of the most prominent radio sources in the
- Earlier today, the WUPPE science team selected NGC 3132, a young
planetary nebula in the constellation Vela, for observation. A
planetary nebula is a bright cloud ejected by the star at its center,
believed to be a phase in the life of certain lower mass stars when
they expel large amounts of material in to space. Sometimes called
the "Eight-Burst" Nebula because its elliptical disk looks like
several oval rings superimposed and tilted at different angles, NGC
3132 is one the few planetary nebulae known to have a binary star
system at its center. WUPPE scientists will examine the light
scattered by dust in the cloud to study the nature of the dust, which
will eventually return to the interstellar medium. Ultraviolet
Imaging Telescope images will test ionization and temperature levels
within the nebula. The Hopkins Ultraviolet Telescope (HUT) took
spectra of the cloud itself and of its binary star.
- The WUPPE team led the Astro telescopes back to the Nova Aquilae
1995. This was the mission's third look at the nova whose outburst,
or sudden increase in brightness, was first observed some three weeks
before the STS-67 launch. Successive polarization measurements during
Astro-2 will allow WUPPE scientists to look for changes in the shape
of the gas disk and for possible clumps ejected during the outburst.
- The HUT team chose the quasar 1211+143 as one of their targets
today. Team members will study the shape of the quasar's ultraviolet
spectrum to learn more about the intrinsic qualities of the quasar
itself. First discovered in the 1960s, quasars are the most luminous
and energetic, as well as the most distant, objects in the universe.
They are believed to be powered by supermassive black holes at their
centers. HUT observations will test the current understanding of
accretion disks, or disks of matter being whirlpooled and sucked into
the black hole.
- WUPPE's Large Magellanic Cloud dust study will continue into this
evening. UIT has chosen two galaxies and an open star cluster for
imaging tonight. The HUT team will lead observations of two quasars,
several individual stars, a planetary nebula, an elliptical galaxy,
and another supernova remnant.
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