Дата: 09 апреля 1998 (1998-04-09)
От: Alexander Bondugin
Тема: Space Station Media Workshop Scheduled For May 12-14 At JSC
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Michael Braukus
Headquarters, Washington, DC April 8, 1998
(Phone: 202/358-1979)
James Hartsfield
Johnson Space Center, Houston, TX
(Phone: 281/483-5111)
NOTE TO EDITORS: N98-26
SPACE STATION MEDIA WORKSHOP SCHEDULED FOR MAY 12-14 AT JSC
Members of the news media are invited to attend press
briefings and hands-on demonstrations at training and
simulation facilities May 12-14 at NASA's Johnson Space Center,
Houston, TX. The activities will provide information about the
International Space Station and its five-year assembly in orbit
that will begin with launches this year.
The workshop will follow a day of standard preflight media
briefings -- on the last Shuttle-Mir docking mission, STS-91 --
that are currently planned for May 11 at Johnson. On May 12, a
series of briefings will describe the International Space
Station, its current status and its assembly in orbit. On May
13 and 14, media representatives can visit a variety of
facilities at Johnson for demonstrations and activities that
will provide familiarity with the station and assembly operations.
Media planning to attend the workshop must fax a written
request for press accreditation to the Johnson Space Center
newsroom at (281) 483-2000 before April 30. Because of limited
capacity in some facilities, attendance at the demonstrations
may be limited to one reporter and/or camera crew per news
media organization. The briefings will be carried live on NASA
Television, available on GE-2, transponder 9C at 85 degrees
West longitude, with vertical polarization. Frequency is on
3880.0 megahertz, with audio on 6.8 megahertz.
Planned briefings for May 12 include: (all times EDT)
9 a.m. International Space Station: Overview and Status
10:30 a.m. International Space Station: Research and Exploration
1 p.m. International Space Station: Assembly in Orbit
2:30 p.m. Flight Control of the International Space Station
News media at Johnson also will receive details and
logistical information concerning coverage of the launch of the
first International Space Station component, the Control Module
or Functional Cargo Block (FGB), from Russia later this year.
Media demonstrations on May 13-14 will include an
opportunity for hands-on activities and briefings by experts in
station engineering, training and operations. Several sessions
of each demonstration will be held each day, and media will be
able to attend in small groups to allow individual attention
and participation. The planned demonstrations include:
* Space Station Training Facility -- viewing and demonstrations
in the U.S. Segment and Russian Segment International Space
Station trainers under development at Johnson, including a new
Soyuz emergency egress trainer.
* Neutral Buoyancy Laboratory -- Adjacent to Johnson's new 6.4-
million gallon spacewalk training pool, high-fidelity mockups
of the first two components, the Control Module and the Node 1
connecting module, will be displayed, along with demonstrations
of spacewalking tools, suits and equipment developed and
flight-tested by NASA in preparation for station assembly.
* Shuttle Cockpit Rendezvous Simulators -- Demonstrations of
the rendezvous and capture activities that will be required to
join the Control Module and Node 1 during Shuttle mission STS-
88 will be viewed in a domed Space Shuttle aft cockpit
simulator, as well as on a desktop rendezvous simulation.
* Virtual Reality Training and Station Mockups --
Demonstrations of Johnson's Virtual Reality Laboratory used by
astronauts to train for upcoming assembly spacewalks will be
performed. Media also will have an opportunity to tour nearby
trainers for the Shuttle and station robotic arms; the
International Space Station full-scale mockups and trainers;
and the X-38 crew return vehicle development facility.
In addition, throughout the three-day workshop, Johnson
personnel with expertise on all aspects of the International
Space Station program and assembly operations will accommodate
as many individual interview requests as possible. Facilities
with International Space Station mockups and backgrounds will
be available for such interviews.
- end -
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=SANA=
Дата: 09 апреля 1998 (1998-04-09)
От: Alexander Bondugin
Тема: Increasing Greenhouse Gases May Be Worsening Arctic Ozone Depletion
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David E. Steitz
Headquarters, Washington, DC April 8, 1998
(Phone: 202/358-1730)
Lynn Chandler
Goddard Space Flight Center, Greenbelt, MD
(Phone: 301/286-9016)
RELEASE: 98-58
INCREASING GREENHOUSE GASES MAY BE WORSENING
ARCTIC OZONE DEPLETION AND MAY DELAY OZONE RECOVERY
In late 1997, larger levels of ozone depletion were
observed over the Arctic than in any previous year on record.
Now, using climate models, a team of scientists reports why
this may be related to greenhouse gases, according to a paper
published in the April 9 issue of Nature.
The study suggests the increase in greenhouse gas emissions
is one possible cause of the observed trends in Arctic ozone
losses and that this may delay recovery of the ozone layer.
The research team, consisting of researchers from NASA's
Goddard Institute for Space Studies (GISS) and Columbia
University, New York, investigated the response of ozone to
projected future emissions of greenhouse gases and ozone-
depleting halogens over time, using the GISS climate model.
This is the first time ever that the interaction between ozone
chemistry and the gradual buildup of greenhouse gases has been
studied in a climate model.
"Buildup of greenhouse gases leads to global warming at the
Earth's surface, but cools the stratosphere. Since ozone
chemistry is very sensitive to temperature, this cooling
results in more ozone depletion in the polar regions," said Dr.
Drew Shindell of Columbia University, the lead author of the
study. NASA will continue research in this area to determine
if these models are accurate.
The "greenhouse effect" is defined as the warming of
climate that results when the atmosphere traps heat radiating
from Earth toward space. Certain gases in the atmosphere --
such as water vapor, carbon dioxide, nitrous oxides and
chlorofluorocarbons -- act like glass in a greenhouse, allowing
sunlight to pass into the "greenhouse," but blocking Earth's
heat from escaping into space.
Ozone, a molecule made up of three atoms of oxygen,
comprises a thin layer of the upper atmosphere which absorbs
harmful ultraviolet radiation from the Sun and protects people,
animals and plants from too much ultraviolet sunlight.
Distribution and concentration of stratospheric ozone are
influenced in two ways by human-driven activity in addition to
natural, seasonal variations. Of first importance is the
direct impact of industrially produced chlorofluorocarbons.
Although ozone levels around the globe are expected to continue
to decline over the next several years, NASA is now detecting
decreasing growth rates of ozone-depleting compounds in the
upper part of the atmosphere, indicating that international
treaties to protect the ozone layer are working. The second
influence on stratospheric ozone levels is the indirect impact
of "greenhouse gases" on atmospheric temperatures. Ozone
destruction is quite sensitive to temperature increases in the
atmosphere.
Since upper atmospheric temperatures in the Northern
Hemisphere during winter and spring generally are warmer than
those in the Southern Hemisphere, ozone depletion over the
Arctic has been much smaller than over the Antarctic during the
1980s and early 1990s. The Arctic stratosphere, however,
gradually has cooled over the past few decades resulting in
very large ozone depletion, especially during 1996-97.
In the simulations performed by Shindell and his team,
temperature and wind changes, induced by increasing greenhouse
gases, clearly alter the dynamics of the atmosphere. According
to this model, as the abundance of greenhouse gases gradually
increases, the frequency of Northern Hemisphere sudden
stratospheric warming is reduced, leading to significantly
colder lower stratospheric temperatures. If proven correct,
this dynamic effect would add to the greenhouse cooling of the
stratosphere.
"Results suggest that the combination of these two cooling
effects causes dramatically increased ozone depletion so that
ozone loss in the Arctic by the year 2020 roughly is double
what it would be without greenhouse gas increases," said Dr.
David Rind of GISS, a co-author of the paper. Increasing
greenhouse gases therefore may be at least partially
responsible for the very large Arctic ozone losses in recent
winters.
The authors caution, however, that though the model
predicts a general trend towards increasing ozone depletion,
the year-to-year variability is quite large, especially in the
Arctic. For example, several years in the late 1990s and early
2000s show very little Arctic ozone depletion, while others
show record losses. In fact, the 1997-98 winter that just
occurred was characterized by significantly less ozone loss
than the preceding six winters. A factor that should be
considered, however, is the consistency in model predictions,
i.e. whether the same results can be reproduced by other models.
According to this model, the severity and duration of the
Antarctic ozone depletion also may increase due to greenhouse
gas-induced stratospheric cooling over the coming decades.
However, ozone in the Antarctic is already so depleted that any
additional losses may be relatively small, Rind added.
The research was conducted by scientists at GISS, The
Center for Climate Systems Research, Columbia University, and
Science Systems and Applications Inc., New York. The GISS
research is part of NASA's Earth Science Enterprise, a long-term
coordinated research effort to study the Earth as a global system.
-end-
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=SANA=
Дата: 09 апреля 1998 (1998-04-09)
От: Alexander Bondugin
Тема: JPL Evening Lectures Highlight Earth Exploration Missions
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MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov
Contact: Stephanie R. Zeluck
FOR IMMEDIATE RELEASE April 7, 1998
JPL EVENING LECTURES HIGHLIGHT EARTH EXPLORATION MISSIONS
"The Earth Observer: Understanding Our Planet from 400 Miles Up" will
be the theme for two free public lectures, one on Thursday, April 16 at 7
p.m. in JPL's von Karman Auditorium, the other on Friday, April 17 at 7 p.m.
in The Forum at Pasadena City College. Seating is limited and will be on a
first-come, first- served basis.
The lectures will be presented by Marguerite Syvertson, outreach
coordinator for the Earth Science Flight Experiments Program and the Earth
and Space Sciences Division. She has been involved as an engineer, scientist
and outreach specialist in the development of the Earth Observing System
(EOS).
Over the next decade, NASA is preparing to launch a suite of missions
that will greatly aid in a more comprehensive understanding of Earth and its
processes. The Earth Observing System AM-1 satellite, scheduled for launch
this summer, is the first of these missions and will provide unprecedented
amounts of data about Earth's surface, oceans and atmosphere that will allow
scientists to study and eventually model changes in Earth's environment and
climate.
EOS AM-1 will carry two instruments onboard: the Multi-Angle Imaging
Spectroradiometer (MISR) and the Advanced Spaceborne Thermal Emission and
Reflection Radiometer (ASTER), which is provided by Japan's Ministry of
International Trade and Industry with scientific support provided by JPL.
These instruments will monitor Earth's biosphere, volcanoes, oceans and
clouds.
Two more spacecraft, one carrying the Atmospheric Infrared Sounder
(AIRS), which will study weather and climate, and the other carrying the
Microwave Limb Sounder (MLS) and the Tropospheric Emission Specrometer
(TES), will study atmospheric composition and will be launched in 2000 and
2002 respectively.
This lecture is part of the von Karman Lecture Series sponsored
monthly by the JPL Media Relations Office. A web site on the lecture series
is located at http://www.jpl.nasa.gov/lecture. For directions and other
information, call the Media Relations Office at (818) 354-5011.
#####
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=SANA=
Дата: 09 апреля 1998 (1998-04-09)
От: Alexander Bondugin
Тема: 25 years of Spacelab -- Go for Space Station [1/2]
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European Space Agency
Press Information Note Nr 10-98
Paris, France 7 April 1998
25 years of Spacelab -- Go for Space Station
A live videotransmission of the Space Shuttle/Neurolab launch
On Thursday 16 April, the Space Shuttle will lift off from the Kennedy
Space Center in Florida, on the Neurolab/STS-90 mission. The flight will
bring together two of the last great frontiers of human exploration --
outer space and inner space -- as it delves into the effects of
weightlessness on the nervous system, one of the most complex and least
understood parts of the human body.
Research will be carried out in Spacelab, the laboratory carried in the
Shuttle's cargo bay. Developed by ESA and built by European industry
between the 1970s and early 1980s, Spacelab heralded a new approach to
the utilisation of space. Now it will be making its final scheduled
flight after 15 years of service.
Later this year, the International Space Station will take over. The
permanently inhabited research facility will begin to be assembled in
space. As of next year, it will provide scientists from around the world
with unique opportunities to research new solutions to Earth-bound
challenges.
To mark the occasion, press are invited to an evening at Noordwijk Space
Expo, next door to ESA/ESTEC in Noordwijk, The Netherlands. Events will
focus on a one-hour, live videotransmission, looking back at the 25
years of the Spacelab programme and looking forward to the beginning of
the Space Station era. The programme will culminate in the countdown to
the launch from Cape Canaveral, with live images of launch preparations
and the lift-off.
Wubbo Ockels, the second ESA astronaut to fly on a Spacelab mission will
be the presenter. Key people from government, industry and the science
community will tell how it was at the beginning, the successes that
Spacelab has encouraged, and their hopes for the future as Europe
prepares for the next step, the Space Station.
Press wishing to take part in the evening should complete the attached
form and return it by fax to ESA/ESTEC Public Relations, fax: (31)
71.565.5728.
25 years of Spacelab -- Go for Space Station
Live videotransmission from Noordwijk Space Expo
Thursday, 16 April 1998 - 8:30-22:00
Programme
18:30 Opening of guest centre at Noordwijk Space Expo
19:00 Welcome
19:40 Live videotransmission broadcast from the future International
Space Station Station European User Information Centre
20:15 Countdown to launch begins, with live feed from Cape Canaveral
20:19 Scheduled lift-off of Columbia (launch window is open for 2.5
hours)
21:40 Conclusions
21:00 Opportunities for interviews
Noordwijk Space Expo
Keplerlaan 3
2201 AZ Noordwijk
The Netherlands
Tel: (31) 71.364.6446
Fax: (31) 71.364.6453
Note to Editors
Neurolab (STS-90) mission
The European Space Agency (ESA) and European scientists are playing a
key role in the next Space Shuttle research mission that will bring
together two of the last great frontiers of human exploration -- outer
space and inner space.
The 16-day international Neurolab flight -- NASA's contribution to the
'decade of the brain' -- will focus on the effects of weightlessness on
the nervous system, one of the most complex and least understood parts
of the human body.
After almost 40 years of manned space flight, the effects of
weightlessness on the brain, spinal cord, peripheral nerves and sensory
organs remain largely unknown.
The Neurolab mission is designed to tackle questions like how the
absence of gravity affects the nervous system and how astronauts gain
their 'space legs', but the research will also have many applications
back on Earth.
A seven-member crew, including three medical doctors, will carry out a
series of neurological studies in Spacelab, the pressurised scientific
laboratory which rides in the Space Shuttle's payload bay. One of the
main items of equipment onboard is an ESA-developed rotating chair,
known officially as the 'off-axis rotator' and part of the VVIS (Visual
and Vestibular Investigation System). This 'human centrifuge' will be
used as a way of investigating the role of the inner ear in detecting
changes in motion and orientation.
Exploiting biomedical techniques and new combinations of sophisticated
measurement and recording devices, the goals of Neurolab are to:
* Use the unique environment of space flight to study fundamental
neurobiological processes.
* Increase understanding of the mechanisms responsible for neurologic and
behavioural changes that occur in space flight.
* Gain knowledge that will help understand how space flight affects human
biology.
* Apply results from space studies to the health, well-being and economic
benefit of people on Earth.
Scientists from France, Germany and Italy are leading seven of the 26
experiments that will take place during the flight, ranging from the
study of the inner ear and sleep patterns to a study of how well
astronauts can catch a ball in microgravity.
Crew members will serve as both subjects and operators in carrying out
the investigations coordinated by scientific teams back on Earth. STS-90
is scheduled for launch from the Kennedy Space Center on 16 April at
20.19 European time.
For more about the Neurolab mission, visit the ESA web site
http://www.esa.int or http://neurolab.jsc.nasa.gov/
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=SANA=
Дата: 09 апреля 1998 (1998-04-09)
От: Alexander Bondugin
Тема: Science Team Chosen For Mars Microprobes Mission (DS-2)
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Douglas Isbell
Headquarters, Washington, DC April 8, 1998
(Phone: 202/358-1547)
John Watson
Jet Propulsion Laboratory, Pasadena, CA
(Phone: 818/354-5011)
RELEASE: 98-59
SCIENCE TEAM CHOSEN FOR TECHNOLOGY VALIDATION MISSION TO EXPLORE
THE SUBSURFACE OF MARS
Nine researchers have been selected to be the Science Team
for the Mars Microprobes, a technology validation mission that
will hitchhike to the red planet aboard NASA's 1998 Mars Polar
Lander mission.
Two identical probes will be carried as a secondary payload
on the lander, due for launch in January 1999. Following an 11-
month cruise, the Microprobes will separate from the lander before
it enters the Martian atmosphere, and then hit the ground at
approximately 400 mph.
During the impact, each microprobe will separate into two
sections: the forebody and its instruments will penetrate up to
six feet (two meters) below the surface, while the aftbody will
remain near the surface to communicate with a radio relay on
NASA's Mars Global Surveyor orbiter while making meteorological
measurements.
The nine selected scientists are:
* David Catling, NASA Ames Research Center, Moffett Field, CA
* Ralph Lorenz, University of Arizona, Tucson
* Julio Magalhaes, NASA Ames Research Center
* Jeffrey Moersch, NASA Ames Research Center
* Paul Morgan, Northern Arizona Univ., Flagstaff
* James Murphy, NASA Ames Research Center
* Bruce Murray, California Institute of Technology, Pasadena
* Marsha Presley, Arizona State Univ., Phoenix
* Aaron Zent, NASA Ames Research Center
The scientific objectives of the Mars Microprobes include
searching for the presence of water ice in the soil and
characterizing its thermal and physical properties. A small drill
will bring a soil sample inside the probe, heat it, and look for
the presence of water vapor using a tunable diode laser. An
impact accelerometer will measure the rate at which the probes
come to rest, giving an indication of the hardness of the soil and
any layers present. Temperature sensors will estimate how well
the Martian soil conducts heat, a property sensitive to different
soil properties such as grain size and water content. A sensor at
the surface will measure atmospheric pressure in tandem with a
sensor on the Mars Polar Lander.
The Mars Microprobes mission, also known as Deep Space-2 (DS-
2), is scheduled to be the second launch in NASA's New Millennium
Program of technology validation flights, designed to enable
advanced science missions in the 21st century.
"I'm delighted with the selection of this excellent group of
investigators. The Mars Microprobe will give us a glimpse of the
subsurface of Mars, which in many ways is a window into the
planet's history," said Dr. Suzanne Smrekar, the DS-2 project
scientist at NASA's Jet Propulsion Laboratory, Pasadena, CA. "The
region of Mars we will explore is similar to Earth's polar regions
in that it is believed to collect ice and dust over many millions
of years. By studying the history of Mars and its climate, we are
likely to better understand the more complex system on our own
planet."
In addition to the miniaturized science instruments capable
of surviving high velocity impact, technologies to be tested on
DS-2 include a non-erosive, lightweight, single-stage atmospheric
entry system or aeroshell; power microelectronics with mixed
digital/analog advanced integrated circuits; an ultra-low
temperature lithium battery; an advanced three-dimensional
microcontroller; and flexible interconnects for system cabling.
"The combination of a single-stage entry vehicle with
electronics and instrumentation that can survive very high impact
loads will enable us to design a whole new class of very small,
rugged spacecraft for the in-situ exploration of the planets,"
explained Sarah Gavit, DS-2 project manager at JPL.
"Slamming high-precision science instruments into the surface
of Mars at 400 mph is very challenging, no doubt about it! But
once this type of technology is demonstrated, we can envision
future missions that could sample numerous regions on Mars or make
network measurements of global weather and possible Marsquakes,"
said DS-2 program scientist Dr. Michael Meyer of NASA
Headquarters, Washington, DC.
Further information on DS-2 is available on the Internet at
the following URL: http://nmp.jpl.nasa.gov/ds2/
The New Millennium Program is managed by JPL for NASA's
Office of Space Science in Washington, DC. JPL is a division of
the California Institute of Technology, Pasadena, CA.
-end-
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=SANA=
Дата: 09 апреля 1998 (1998-04-09)
От: Alexander Bondugin
Тема: Water Vapor On Titan And Remote Galaxies ... [1/2]
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European Space Agency
Press Information Note No. 09-98
Paris, France 7 April 1998
New water and remote galaxies complete ISO's observations
Water vapour detected on Saturn's largest moon, Titan, and infrared
galaxies identified at immense distances are among the latest results
from the European Space Agency's Infrared Space Observatory, ISO. At a
press briefing in London today (7 April) ESA's director of science,
Roger Bonnet, said "ISO is one of the most successful space
observatories, and in the infrared it has had no rival." Its discoveries
will change our views on the Universe.
ISO's operational teams at ESA's ground station at Villafranca near
Madrid have been hurrying to provide the world's astronomers with as
many observations as possible. They have long anticipated the exhaustion
of ISO's vital supply of liquid helium, which cooled the infrared
telescope and its instruments to their operating temperatures, close to
absolute zero. Two weeks after ISO was put into orbit on 17 November
1995 by an Ariane 44P launcher, the external parts of the cooling system
had settled to the operating temperature. The specification required
that ISO should then operate for at least 18 months -- implying that
operations might have to end in May 1997.
Thanks to superb engineering by European industry, which built the
spacecraft and its super-cool telescope, ISO has given astronomers
almost a year longer than that. During the extra time the count of ISO's
observations of cosmic objects has risen from 16,000 to about 26,000.
Among the benefits of ISO's longevity has been the chance to examine an
important region of the sky, in and around the constellation of Orion.
This was not accessible in the nominal mission but has now been observed
in two periods.
Four international teams, supported by national funding agencies,
supplied the instruments to analyse the infrared rays received by ISO's
telescope. The principal investigators leading the teams are Dietrich
Lemke (Heidelberg, Germany) for the versatile photometer ISOPHOT,
Catherine Cesarsky (Saclay, France) for the camera ISOCAM, Thijs de
Graauw (Groningen, the Netherlands) for the Short Wavelength
Spectrometer SWS, and Peter Clegg (London, UK) for the Long Wavelength
Spectrometer LWS.
Water vapour on Titan
A big difference between ISO and the only previous infrared astronomy
satellite (IRAS 1983) has been its ability to examine individual objects
across a wide range of accurately defined infrared wavelengths. Many
spectra showing patterns of intensities at the different wavelengths
have enabled astronomers to deduce the presence of diverse materials in
interstellar space, in the surroundings of stars, and in other
galaxies.
As previously reported, ISO has identified stony materials, tarry
compounds of carbon, and vapours and ices like water and carbon
monoxide. Together they give the first clear picture of how Mother
Nature prepares, from elements manufactured in stars, the ingredients
needed for planets and for life itself.
Particularly striking for the human imagination are ISO's repeated
discoveries of water in the deserts of space. They encourage
expectations of life elsewhere in the Universe. Water has turned up
around dying stars, newborn stars, in the general interstellar medium,
in the atmospheres of the outer planets and in other galaxies too. A
link to the Earth's oceans and the water we live by comes in the water-ice
long known to be a major ingredient of comets, which are relics from the
era of planet-building.
A further link to the investigation of the origin of life is the
apparent detection of water vapour in the mysterious atmosphere of
Saturn's largest moon, Titan. A preliminary announcement comes from an
international team headed by Athena Coustenis of Paris Observatory and
Alberto Salama of the ISO Science Operations Center at Villafranca.
The team used ISO's Short Wavelength Spectrometer during several hours
of observations last December, when Titan was at its farthest from
Saturn as seen by ISO. Emissions at wavelengths of 39 and 44 microns
showed up, as an expected signature of water vapour. The news will
excite the scientists involved in ESA's probe Huygens, launched last
year aboard NASA's Cassini spacecraft. It will parachute into Titan's
atmosphere to see what the chemistry of the Earth may have been like
before life began.
"Water vapour makes Titan much richer," comments Athena Coustenis. "We
knew there was carbon monoxide and carbon dioxide in Titan's atmosphere,
so we expected water vapour too. Now that we believe we've found it, we
can expect to better understand the organic chemistry taking place on
Titan and also the sources of oxygen in the Saturnian System. After ISO,
the Huygens probe will reveal the actual degree of complexity in a
mixture of elaborate organic molecules closely resembling the chemical
soup on the young Earth."
Ballet corps of young stars
Infrared images of the spectacular Orion star-forming regions, at a
distance of approximately 1500 light years, are bonuses from ISO's
extended life. In the Horsehead Nebula, visible light shows a large dark
dust cloud from which a black wisp shaped like a horse's head protrudes
into a luminous cloud of gas. When seen by ISO's camera ISOCAM, dense
parts of the dusty region appear as shiny filaments and the horse's head
almost disappears. Young stars are detected in the horse's forehead and
in the nearby nebula NGC 2023.
Other well-known nebulae in the Orion region include NGC 2068 and NGC
2071. Emission by carbon compounds (polycyclic aromatic hydrocarbons or
PAH) makes the infrared nebulae spectacular, as seen by ISOCAM. And
thanks to ISOCAM's sensitivity and the ability of infrared rays to
penetrate a dust cloud better than visible light, ballet corps of young
stars appear on the stage, seen as spots in the centre of these two
nebulae. This is not surprising, because the dense, dusty regions called
molecular clouds are often the breeding grounds of new stars, but ISOCAM
detects fainter and more obscured objects.
"We have used ISOCAM to make a census of families of young stars,"
comment Lennart Nordh and Goran Olofsson of Stockholm University, who
lead a team of astronomers from Sweden, France, Italy, the UK and ESA.
"By comparing the intensities of the point-like objects at different
infrared wavelengths we can efficiently identify the ensemble of young
stars still embedded in its parental molecular clouds."
>From their study of ISO's early observations of four star-forming
clouds, the astronomers report the detection of small stars. "Almost 300
young stars have been identified to date, many of which were previously
not recognized," Nordh and Olofsson say. "Most of the latter objects
have luminosities 10-100 times lower than revealed by earlier
observations. Our preliminary analysis indicates that at least ten per
cent of the embedded young stars will become small brown dwarfs, or
ownerless super-planets, less than one-tenth of the mass of the Sun."
Hа сегодня все, пока!
=SANA=
Дата: 09 апреля 1998 (1998-04-09)
От: Alexander Bondugin
Тема: Water Vapor On Titan And Remote Galaxies ... [2/2]
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Colliding galaxies
Some galaxies are unusually bright in the infrared because of cosmic
traffic accidents that bring them into collision with other galaxies.
The result is a frenzy of star formation called a starburst. The
explosion of short-lived stars then creates a pall of warm dust which
ISO observes in the infrared. The relative intensities of different
wavelengths enable astronomers to distinguish starburst events from
other sources of strong infrared rays, such as the environment of a
black hole in the nucleus of a galaxy. Collisions and starbursts play an
important part in the evolution of galaxies.
A famous pair of colliding galaxies called the Antennae was one of the
first objects to be examined by ISO. Continuing study of the Antennae
over the past two years has revealed a clear picture of a starburst
occurring exactly where the dense disks of the galaxies intersect. The
nuclei of the two galaxies are plainly distinguished too.
Centaurus A is a galaxy that first attracted the attention of
astronomers by its strong of radio emissions. In its visible appearance,
a large, round (elliptical) galaxy has a dark band across its face. This
too turns out to be the result of a galactic collision. The dark band is
a flat, disk-shaped galaxy seen almost edge-on. Centaurus A is the
nearest case of a phenomenon seen elsewhere by ISO, in which a flat
galaxy has merged with an elliptical galaxy while preserving its flat
configuration.
ISOCAM gives an image of Centaurus A in which the disk galaxy is the
more conspicuous object. The orientation of the disk becomes clear. It
is at right angles to the axis of the radio-emitting regions, which are
powered by jets of electrons driven by a black hole in the centre of the
galaxy. Excited emissions detected by ISO's Short Wavelength
Spectrometer also indicate the presence of an active black hole.
"Centaurus A is an example of ISO's magic," says Catherine Cesarsky of
CEA Saclay in France, leader of the ISOCAM instrument team. "It
transforms opaque clouds seen by visible light into glowing scenes in
the infrared. The same thing happens in dust clouds hiding newborn
stars, and on a huge scale in dusty starburst galaxies -- which become
infrared beacons lighting our way deep into the Universe."
Distant galaxies seen through the holes in the sky
When ISO was launched, one of the hopes for the space observatory was
that it would detect galaxies made luminous by starburst events, or by
black-hole activity, very far away in space and therefore far back in
time. Dust in our own Milky Way Galaxy usually obscures the remotest and
faintest galaxies. But when they look northwards and southwards, at
right-angles to the disk of the Milky Way, astronomers find holes in the
dust clouds through which distant galaxies are discernible.
Both for ISO and the Hubble Space Telescope these holes have been
special targets for observations with long exposures, to reveal faint
galaxies. ISOCAM results through the northern hole, by a Japanese-led
team, were reported last year in an ESA Information Note (25.97) and a
picture release (ESA/ISO 97:8/1). They revealed many infrared-luminous
galaxies billions of light-years away, from an era corresponding with
about half the present age of the Universe. Even more distant and
earlier galaxies may be present in ISO's observations, including some
objects not yet seen by visible light.
Results released at the London press briefing on ISO include "deep
field" examinations by groups of astronomers led by Catherine Cesarsky
of CEA Saclay and Michael Rowan Robinson of Imperial College, London,
analysing the northern and southern images respectively. In the northern
deep field, when ISOCAM observations are superimposed on a Hubble
picture of the same region, they pick out spiral galaxies experiencing
starbursts. A different signature comes from large elliptical galaxies
whose visible light has been shifted into the infrared by the expansion
of the Universe. The astronomers estimate that some of the objects seen
by ISOCAM are so far away that the Universe was only one-third of its
present age when they emitted the radiation seen today.
The first ISO images from the opposite direction in the sky, in the
southern deep field, show similar objects, again at great distances. A
preliminary analysis indicates the presence of of 30-40 remote galaxies
seen at a wavelength of 7 microns and 22-30 at 15 microns. One
interesting source, bright in the infrared, is not seen by visible light
even in a prolonged examination by the CTIO 4-metre telescope in Chile
(A. Walker). Astronomers suspect that this object is undergoing an
especially violent period of star formation. The interpretation can be
checked when Hubble and other telescopes have a chance to examine this
scene.
Besides illuminating the evolution of the galaxies, ISO's deep field
results are encouraging for scientists planning another of ESA's
astronomical space projects, FIRST. Its longer wavelengths will
penetrate even deeper into the unknown.
Non-stop discoveries
The extended life was not the only outcome that made ISO a triumph for
ESA, European industry and those responsible for its operations. The
pointing accuracy of the telescope turned out to be ten times better
than required in the specification and its jitter was one-fifth of what
was considered tolerable. Stray light in the optical system was too
small to measure. The scheduling systems achieved science observations
for 90-95 per cent of the available time. Much of the rest of the time,
when ISO was turning to new targets, was spent in mapping parts of the
sky at a wavelength of 200 microns.
Activity concerning ISO will continue at the Villafranca ground station
until the year 2001, long after the completion of the observational
phase of the mission. During the space operations, the main objective
was to make as many observations as possible. Thorough analysis and
interpretation of the results will take several years.
"We still have plenty to do," says Martin Kessler, ESA's project
scientist for ISO. "Our team at Villafranca is preparing a complete
archive of ISO data on 500-1000 compact disks, after reprocessing with
improved software. We'll release part of this archive to the world-wide
astronomical community in the autumn of this year, and the rest in 1999.
We shall also advise the astronomers who have used ISO, about the
particular requirements for handling the data from each instrument, and
we'll be doing some astronomy ourselves. There are far more results
still to come from ISO."
Europe's infrared astronomers are already busy preparing ESA's FIRST and
Planck missions, due for launch early in the new century. FIRST will
observe long infrared wavelengths in the sub-millimetre range, while
Planck will map the cosmic microwave background far more accurately than
NASA's COBE mission did, to reveal the clumps of matter from which
galaxies evolved. Also under study by ESA is a possible interferometer
mission using a combination of infrared telescopes. In principle it
might observe and characterize planets in orbit around other stars.
Meanwhile, Europe's space astronomy programme continues apace in other
directions. ESA's participation in the Hubble Space Telescope and its
eventual successor assures access to those important instruments for
Europe's astronomers. The release in 1997 of the catalogues from ESA's
unique star-mapping mission Hipparcos provided all astronomer with
amazingly precise data for sizing up the stars and the wider Universe.
Next year will see the launch of ESA's XMM satellite to observe X-rays
from the Universe with the most ingenious and sensitive X-ray telescopes
ever made. It will be followed by Integral in 2001, which will
investigate cosmic gamma-rays with clever imaging devices called coded
masks, and ultra-sensitive detectors.
"Our aim in space astronomy is that every ESA mission should be the best
in the world at the time of its launch," says Roger Bonnet, ESA's
director of science. "ISO is a shining example. It has revolutionized
infrared astronomy. It has given us wonderful insights into cool and
hidden places in the Universe, and into the origins of water and other
materials to which we owe our very existence. A mission of this scale
and complexity was feasible for Europe only through the multinational
collaboration coordinated by ESA."
See ISO's results on the World Wide Web, or on a CD
Immediate access to information about ISO and its results, including a
picture gallery, is available via the Internet: http://isowww.estec.esa.nl
For the assistance of journalists, ESA's ISO team has also prepared a
compact disk containing the same information as the website, together
with previously published information about ISO and its results.
For further information, contact ESA Public Relations Division Tel:
+33.(0)1.53.69.71.55 Fax: +33(0)1.53.69.76.90
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