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Interstellar Medium And The Milky Way
interstellar medium and the Milky Way.
http://www.astronomynotes.com/ismnotes/s1.htm

Extractions: This material (including images) is . See my for fair use practices. Our solar system is inside a large galaxy known as the Milky Way . All of the stars you can see at night and several hundred billion more are all bound together gravitationally into a huge cluster called a galaxy . Most of the stars in our galaxy are far enough away that they blend together in a thin band across the sky. If you are fortunate enough to view a dark sky outside of the glare of the city lights, you will see this milky band running through the constellations Cassiopeia, Perseus, Taurus, Monoceros, Vela, Crux, Norma, Sagittarius, Scutum, Aguila, Cygnus, and Lacerta. To people of long ago, this band looked like milk had been spilled along a pathway, so it was called the Milky Way. This chapter covers the radical discoveries made in the 20th century of the nature of the Milky Way and our place in it. The vocabulary terms are in boldface Go to next section last updated: 25 May 2001 Is this page a copy of Strobel's Astronomy Notes?
Interstellar Medium And The Milky Way
interstellar medium (ISM). This material is called the interstellarmedium. The interstellar medium makes up between 10 to 15% of
http://www.astronomynotes.com/ismnotes/s2.htm

Extractions: This material (including images) is . See my for fair use practices. Select the photographs to display the original source in another window. Most of the ground-based telescope pictures here are from the Anglo-Australian Observatory (AAO-used by permission). Links to external sites will be displayed in another window. Though the space between the stars is emptier than the best vacuums created on the Earth (those are enclosed spaces devoid of matter, not the household cleaning appliances), there is some material between the stars composed of gas and dust. This material is called the interstellar medium . The interstellar medium makes up between 10 to 15% of the visible mass of the Milky Way. About 99% of the material is gas and the rest is ``dust''. The interstellar medium affects starlight and stars (and planets) form from clouds in the interstellar medium, so it is worthy of study. Also, the structure of the Galaxy is mapped from measurements of the gas. The dust is made of thin, highly flattened flakes or needles of graphite (carbon) and silicates (rock-like minerals) coated with water ice. Each dust flake is roughly the size of the wavelength of blue light or smaller. The dust is probably formed in the cool outer layers of red giant stars and dispersed in the red giant winds and planetary nebulae.
The Interstellar Medium
Electronic Editor H. Payne. The interstellar medium. Deuterium in theLocal interstellar medium R. Ferlet, M. Lemoine, and A. VidalMadjar;
http://www.stsci.edu/stsci/meetings/shst2/node83.html
Interstellar Medium
next up previous Next Normal Galaxies Up BAAS Report for Space PreviousStars and Star. interstellar medium. R. Allen, McKellar
http://www.stsci.edu/stsci/baas96/node4.html

Extractions: Next: Normal Galaxies Up: BAAS Report for Space Previous: Stars and Star R. Allen, McKellar (NRC Ottawa), Loinard, and Lequeux (Paris), have carried out a search for the CO-H2 dimer in the ISM near 3 mm wavelength using frequencies computed from IR-absorption cell data supplied by McKellar. Since the binding energy of this ``van der Waals" complex is very low it is easily destroyed by collisions, and the abundance of this dimer may be a sensitive tracer of low temperatures in the ISM. The search was carried out using the 30m IRAM radio telescope; several different Galactic cold molecular clouds were examined for traces of emission, and an absorption experiment was done using the (presumed) extragalactic source 2013+370. No detections were recorded, and useful upper limits were obtained. A paper describing the experiment is in preparation. J. Kingdon and Williams completed a revision of Williams' Emission Line Chart, which was based on an extensive grid of photoionization models. The results of this grid were used to identify those line ratios which are insensitive to conditions in the gas and which are therefore good for deriving abundances in emission-line objects. Kingdon is continuing his investigation into temperature fluctuations in gaseous nebulae in order to explain the observed discrepancy between abundances derived from recombination and collisionally excited lines. He is currently studying whether radial variations in abundances can resolve the discrepancy.
Stars - Interstellar Medium
Stars interstellar medium. 4/2/98. Click here to start. Table of Contents.Stars - interstellar medium. interstellar medium Defined. PPT Slide.
http://www.physics.gmu.edu/classinfo/astr103/CourseNotes/Ppt/Lec04_pt7_interstel
According To An Interstellar Medium...
When she says virtually, she's serious The interstellar medium now has about 0.1hydrogen atom per cubic centimeter (and that's 1,000 times as dense as the
http://whyfiles.org/017planet/gas_cloud2.html

Extractions: It looks as if our trusty ol' solar system is poised to enter a "dense" cloud of interstellar gas, an event that would change our atmosphere in unpredictable ways. But not to worry it's not going to happen for several tens of thousands of years. Within about 50,000 years, the solar system could enter a much denser portion of the interstellar medium. How would that affect our atmosphere? Yellow arrow: sun's movement through space. White arrows: movement of gas cloud. Courtesy of Priscilla Frisch, the University of Chicago. Could the denser gas in "outer space" affect the atmosphere, and conditions on our planet? That's something that Priscilla Frisch, an astronomer at University of Chicago, wonders about. She notes that for the past 5 to 10 million years, Earth has occupied a region that's "virtually empty." When she says "virtually," she's serious : The interstellar medium now has about 0.1 hydrogen atom per cubic centimeter (and that's 1,000 times as dense as the last cloud). Astronomers don't bother comparing the density of the medium to that of liquid water, which weighs one gram per cubic centimeter (cc). Instead, they count the number of hydrogen atoms per cc. (For comparison, there are 700 billion billion hydrogen atoms in a cc of pure hydrogen gas at the pressure at Earth's surface). Frisch suggests that the vacuum-like interstellar medium may have promoted a stable atmosphere. "If the sun was being buffeted by a dense interstellar medium, it would probably affect our climate, although we don't know exactly how."
Interstellar Medium
interstellar medium Group. Welcome to our Webpages. The three members of the group are
http://www-obs.cnrs-mrs.fr/matiere/milieuanglais.html
CfA Star Formation/Interstellar Medium Group Home Page
This is the top page of the Star Formation/interstellar medium Group at the HarvardSmithsonianCenter for Astrophysics meta name=. Frame ALERT!
http://cfa-www.harvard.edu/sfgroup/
Radio Astronomy, The Interstellar Medium, Star Formation For
The interstellar medium (ISM) Radio Astronomy, Star Formation, the ISM.
http://cfa-www.harvard.edu/~rplume/vhs/vhs.html
NebulaIS - Interstellar Medium
nebulae, now called galaxies, which are enormous collections of stars and gas; andthe galactic nebulae, which are composed of the interstellar medium (the gas
http://www.nebulais.com/definition.html

Extractions: – (Latin: "mist," or "cloud"), plural NEBULAE, or NEBULAS, any of the various tenous clouds of gas and dust that occur in interstellar space. The term was formerly applied to any object outside the solar system that had a diffuse appearance rather than a pointlike image, as in the case of a star. This definition, adopted at a time when very distant objects could not be resolved into great detail, unfortunately includes two unrelated classes of objects: the extragalactic nebulae, now called galaxies, which are enormous collections of stars and gas; and the galactic nebulae, which are composed of the interstellar medium (the gas between the stars, with its accompanying small solid particles) within a single galaxy. Today the term nebula generally refers exclusively to the interstellar medium.
ISO Interstellar Medium Image Gallery
ISO interstellar medium Image Gallery. ISOCAM picture of the rho Ophiuchicloud ISOCAM picture of the rho Ophiuchi cloud. ISOCAM picture
http://www.iso.vilspa.esa.es/galleries/ism.html
Notes On The Interstellar Medium For Asph 503
This page gives links that are useful for the students in ASPH503,the interstellar medium course here at U of Calgary. Below are
http://www.iras.ucalgary.ca/~volk/asph503.html

Extractions: This page gives links that are useful for the students in ASPH503, the Interstellar Medium course here at U of Calgary. Below are links to PDF forms of my class notes; the PDF conversion is not always 100% correct for some reason that I have not been able to determine. However I think the files can be printed if desired. PDF (portable document format) is from Adobe Systems, and the Adobe Acrobat reader is needed to view them. The notes more or less replace a textbook, since the field is moving so rapidly and all the available textbooks that I know of are out of date. I have much more emphasis on molecular cloud properties and star formation than is normal in ISM textbooks, since these areas are two of the currently most active aspects of ISM research. The same is true of extragalactic ISM research, but there I was only able to put in a small amount of material mostly for comparison with the situation in the Galaxy. One thing that I could not make for the notes was a copy of the Columbia CO map of the Galaxy by Dame et al. This is refered to in the notes and there are some filler pages where I photocopied the original large-scale map from T. M. Dame et al. (1987; ApJ, 322, 706-720). A nice colour poster of this map is available from Dr. Dame. Some WWW images from the poster are found at this link These notes are free for the downloading, but I stress that they are by no means perfect or even polished. Some parts of them may reflect my ignorance rather than my knowledge. It was educational for me to put the notes together; things have changed a lot since I took this sort of course in 1981.
The Interstellar Medium
The interstellar medium (ISM). The Orion Nebula The interstellar mediumis the material that lies between the stars in a galaxy.
http://hea-www.harvard.edu/~juda/ism/ism.html

Extractions: The interstellar medium is the material that lies between the stars in a galaxy . This material can exist in several phases with a wide range in temperature (from tens of degrees to tens of millions of degrees Kelvin). In the coldest regions the material consists of molecular gas and dust; in the hottest regions the material is almost completely ionized. Return to my homepage Dr. Michael Juda
The Interstellar Medium
THE interstellar medium. The space between the stars is referred toas the interstellar medium, abbreviated ISM. By volume, the ISM
http://lep694.gsfc.nasa.gov/lepedu/terms/ism.htm

Extractions: THE INTERSTELLAR MEDIUM The space between the stars is referred to as the interstellar medium, abbreviated ISM. By volume, the ISM is the largest "object" in the Milky Way Galaxy. Although the mass of the interstellar medium is not known with certainty, the ISM has at least enough matter to make billions of stars like our Sun. The ISM is 99% gas and 1% dust. Hydrogen is by far the most abundant element in the ISM, accounting for about 90% of the gas. The remaining 10% of the gas is composed of other elements, with helium having by far the greatest abundance. Carbon- and silicate-grains make up the dust component of the ISM, with particle sizes ranging from 0.1 - 1 micrometers (4 - 40 millionths of an inch), although some grains are considerably smaller. Over a hundred different molecules have been found to date in interstellar space, both in clouds and on interstellar grains. Although the interstellar medium has an average density of about 1 atom for every cubic centimeter, the distribution of atoms is far from uniform. Most conspicuous are the clouds of gas and dust that populate the ISM. The clouds are called nebulae (singular = nebula), and three types are shown on this page. The first type is emission nebulae, among the most famous, most photographed, and most beautiful objects in the heavens. The Rosette Nebula (at left) is a good example, its characteristic red color being due to light released by hydrogen atoms around 10,000 K (17,500 F). The Orion Nebula, a favorite of backyard astronomers, is another example of an emission nebula. These objects are often found near young stars. Few molecules are hardy enough to exist at the high temperatures of emission nebulae, and so consequently scientists find that they contain mostly atoms and atomic ions.
The Violent Interstellar Medium Of Nearby Dwarf Galaxies
Next Section On Holes and Shells, Contents Page Volume 16, Number 1.The Violent interstellar medium of Nearby Dwarf Galaxies. Fabian Walter.
http://www.atnf.csiro.au/pasa/16_1/walter/paper/
SUPERNOVA REMNANTS, PULSARS AND THE INTERSTELLAR MEDIUM - SUMMARY OF A WORKSHOP
SUPERNOVA REMNANTS, PULSARS AND THE interstellar medium SUMMARY OF AWORKSHOP HELD AT U SYDNEY, MARCH 1999. SUPERNOVA REMNANTS, PULSARS
http://www.atnf.csiro.au/pasa/17_1/dwarkadas/paper/

Extractions: brian@mso.anu.edu.au We summarise the proceedings of the SRCfTA workshop on ``Supernova Remnants, Pulsars and the Interstellar Medium'' that was held at the University of Sydney on Mar 18 and 19, 1999. Keywords:masers shock waves turbulence supernovae: general supernovae: individual (SN 1987A, SN 1993J) pulsars: general supernova remnants gamma rays: bursts
Astronomy: Physics For The Interstellar Medium
Physics for the interstellar medium. KS de Boer. Structure and evolution of theinterstellar medium. Literature A full writeup in english is available Tel.
http://www.astro.uni-bonn.de/~deboer/class-ism.html

Extractions: K.S. de Boer A class in the ``Summersemester'' (as of SS02) This class is also part of the Bonn International Physics Programme The most important physical processes taking place in interstellar gas are presented, together with their relevance for observational astronomy (all wavelength domains). Specific topics include: Literature:
The Interstellar Medium
Deutsch The interstellar medium. On the other hand, we observe interstellar mediumfull of fissures, caused by the explosion of a dying star at the of its life.
http://www.astro.uni-bonn.de/~webaiub/Dozentenfuehrer/ISM/index-e.html

Extractions: A stronomische I nstitute der U B onn The space between the stars is not empty, but filled with interstellar matter. Interstellar matter displays many very different physical properties. On one hand, stars have their birthplaces in the densest parts of interstellar clouds, where we find molecules intermixed with dust. On the other hand, we observe interstellar medium full of fissures, caused by the explosion of a dying star at the of its life. The star returns mass and energy back to the interstellar medium. As a result, we see shock waves penetrating the interstellar medium and heating up the gas to millions of degrees Kelvin. The studies in particular the cold and the hot phase of the interstellar Medium of the Milky Way. In the framework of a "Sonderforschungsbereich" (SFB), in collaboration with the and the we study the interaction between star formation and the dynamics of galactic halos and galaxies with low mass content. Further information can be found on ISM Homepage , and the corresponding internet pages of the KOSMA X-ray and HI group At the Sternwarte investigations concentrate on the very local gas, gas in the Milky Way halo, and gas in the Magellanic Clouds, using visual and ultraviolet (
The Interstellar Medium
The interstellar medium. PHY410. ISM. Dyson, JE Williams, DR The Physics of theinterstellar medium Institute of Physics Publishing, (1997) ISBN 0-7503-0460-X.
http://www.ph.qmw.ac.uk/ughandbook/ism.htm
Planetary Nebulae And The Interstellar Medium: Table Of Contents
Translate this page Institut für Astronomie und Astrophysik. Abteilung Astronomie. Sand 1, D-72076Tübingen, Germany, Uni logo. Planetary Nebulae and the interstellar medium.
http://astro.uni-tuebingen.de/~wilms/teach/ism/

Extractions: Abteilung Astronomie werner@astro.uni-tuebingen.de wilms@astro.uni-tuebingen.de The following table contains links to gziped PS-files of the viewgraphs of the class on Planetary Nebulae and the Interstellar Medium Feedback concerning these slides is appreciated. Please email your comments to Klaus Werner ( werner@astro.uni-tuebingen.de wilms@astro.uni-tuebingen.de ). You are free to use these slides in your class, however, we would like to hear from you such that we can keep you informed concerning updates of these viewgraphs. Upon request and where available, we will also make the TeX sources of the viewgraphs available. Einführung Gziped Postscript (5.5 MB, uncompressed: 7.2 MB) and PDF (4.5 MB) of this chapter

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