STS-67 Day 3 Highlights
Back to STS-67 Flight Day 02 Highlights:
- On Saturday, March 4, 1995 at 6 a.m. CST, STS-67 Payload Status Report # 05
reports: (2/5:22 MET) The Hopkins Ultraviolet Telescope
(HUT) led the observations of several celestial objects, starting with
AX Persei, a double star system consisting of a red star paired off
with a blue star in what is known as a symbiotic binary. This means
that the two stars differ greatly in their temperature ranges. They
are believed to be a pair in which gas from a large, cool star falls
onto a smaller, but more massive companion. Not much is known about
how these stars interact, and data from these observations will help
improve current measurements of the hot star component's temperature
and gas emissions.
- The Wisconsin Ultraviolet Photo-Polarimeter Experiment (WUPPE)
also obtained "great observations" of the AX Persei star system,
according to WUPPE guest investigator Dr. Regina Schulte-Ladbeck. In
a live interview with TV station WPXI in Pittsburgh, Pennsylvania,
Dr. Schulte-Ladbeck described the instrument's view of the stellar
pair as "picture perfect from an operational point of view."
- Dr. Schulte-Ladbeck also used HUT and WUPPE to obtain spectral
measurements of a Wolf-Rayet star known as EZ Canis Majoris.
Wolf-Rayet stars are thought to represent one of the final phases of
evolution in massive stars that are between 100,000 and 1,000,000
times as bright as the Sun. Wolf-Rayet stars have powerful stellar
winds, or emissions of ionized gas, that quicken the stars' aging
process. The composition of these stellar winds is also important
because the elements they contain play a significant role in forming
the basic chemistry of life. According to Dr. Schulte-Ladbeck, last
night's measurements alone, of the strength and composition of this
stellar wind, have already yielded "more information about EZ Canis
Majoris than we ever got on Astro-1."
- The Astro-2 scientists also turned their attention to one of
their prime targets of investigation, the brightest known Seyfert
galaxy, NGC 4151. Seyfert galaxies are known for their extremely
bright and compact centers and radiate energy most strongly in the
ultraviolet and X-ray wavelengths.
- Ultraviolet Imaging Telescope (UIT) observations included
images of a globular cluster, NGC6752, and a spiral galaxy, M101.
Globular clusters are collections of relatively old stars, and they
are particularly suitable for observations by UIT due to the presence
of hot stars which emit most of their radiation in the ultraviolet
range. This enables UIT astronomers to locate hot white dwarf stars,
hot binary systems and objects associated with sources of X-rays.
- Spiral galaxies, like our Milky Way, are flattened discs with
central bulges or nuclei from which the galaxies' arms extend. M101
is a big spiral galaxy with spiral arms that are not tightly wound.
UIT's ultraviolet imaging offers a powerful new tool for the study of
this spiral structure, since it emphasizes hot stars, hydrogen and
- Early in the morning, the Astro-2 instruments made observations
of the Cygnus Loop, a middle-aged supernova remnant. A supernova is
one of the most powerful explosions in the universe, and it occurs at
the end of a very massive star's life after the star's fusion reaction
stops. The Cygnus Loop is of particular interest because it reveals
details about the structure and speed of shock waves from the
explosion as they travel through the interstellar medium.
- Jupiter had became a focus of investigation earlier in the
evening, especially for the HUT science team who obtained very good
spectral data on the planet's equator. The planet is believed to have
a reservoir of heat energy left over from its creation, since Jupiter
radiates twice as much energy as it receives from the Sun. HUT
scientists are particularly interested in the planet's immense
magnetosphere, a region of charged particles controlled by Jupiter's
- On Saturday, March 4, 1995 at 1 p.m. CST, STS-67 MCC Status Report # 06
reports: During the past shift, the crew received word from
scientists who designed the Australian ultraviolet experiment that is
flying in two Getaway Special canisters in the cargo bay. The
experimenters reported they have achieved 100 percent of desired
observations and expressed a sincere thanks and appreciation for the
support they received during this mission. In addition, Jernigan and
Lawrence participated in an interview with National Public Radio as
Durrance supported the Astro-2 observations.
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