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Topic: Bok globule


  
  Bok globule   (Site not responding. Last check: 2007-10-20)
An image of Bok globules in the [[H II region IC 2944, taken with the WFPC2 instrument on the Hubble Space Telescope]] A Bok globule is a dark cloud of dense dust and gas in which star formation is taking place.
Bok globules are found within H II regions, and typically have a mass of about 10–50 solar masses contained within a region about a light year or so across
Bok globules were first observed by astronomer Bart Bok in the 1940s.
bok-globule.iqnaut.net   (347 words)

  
  Bok globule - Wikipedia, the free encyclopedia
A Bok globule is a dark cloud of dense dust and gas in which star formation is sometimes taking place.
Bok globules are found within H II regions, and typically have a mass of about 10–50 solar masses contained within a region about a light year or so across
Bok globules were first observed by astronomer Bart Bok in the 1940s.
en.wikipedia.org /wiki/Globule   (473 words)

  
 globule
A small, dense, round cloud of dust and gas that absorbs radiation and appears as a fl blob when seen against the background of a bright nebula or star field; also known as Bok globule after Bart Bok who first drew attention to them and suspected they might be protostars.
While it is generally assumed they are the cores of fragments of molecular clouds that are in the process of collapsing to form individual stars, they could also be fragments that have become hung up by a combination of internal magnetic and turbulent pressure and are failed star-forming cores.
Globules are the smallest and most regular features of the interstellar medium.
www.daviddarling.info /encyclopedia/G/globule.html   (225 words)

  
 Bok, Bart J(an) - Hutchinson encyclopedia article about Bok, Bart J(an)
Bok, born in Hoorn, was educated at Leiden and Groningen in the Netherlands and in the USA at Harvard, where he remained and became professor 1947.
Bok also discovered small, circular dark spots, which were best observed against a bright background.
Bok suggested that the globules were clouds of gas in the process of condensation and that stars might be in the early stages of formation there.
encyclopedia.farlex.com /Bok%2c+Bart+J(an)   (226 words)

  
 Bok globule: Facts and details from Encyclopedia Topic   (Site not responding. Last check: 2007-10-20)
A Bok globule is a dark cloud of dense dust and gas in which star formation Star formation quick summary:
Bok globules are found within H II region[For more facts and a topic of this subject, click this link]s, EHandler: no quick summary.
Bok globules were first observed by astronomer Bart Bok[For more facts and a topic of this subject, click this link] in the 1940s[For more facts and a topic of this subject, click this link].
www.absoluteastronomy.com /encyclopedia/b/bo/bok_globule.htm   (879 words)

  
 mobileCatalog: Stellar Evolution
Bok suggested that certain isolated and distinct globules obscuring background light in space were in fact evidence of an important preliminary stage in the formation of protostellar disks leading to the birth of stars such as our sun.
The team started by selecting ten Bok globules for observation based on small apparent size, near-circular shape, distance from neighboring nebulosity, proximity to the Earth (less than 1700 LYs away), and accessibility to near-infrared and radio wave collecting instruments located in both the northern and southern hemispheres.
Once candidate Bok globules were selected, the team subjected each of them to a battery of observations designed to determine their mass, density, temperature, size, and if possible, the amount of pressure applied on them by the ISM and neighboring starlight.
www.astrobio.net /cgi-bin/mobileCatalog.cgi?sid=1617&ext=.html   (1116 words)

  
 Universe Today - Star Forming Dust Clouds Imaged by Hubble
These opaque, dark knots of gas and dust are called "Bok globules," and they are absorbing light in the center of the nearby emission nebula and star-forming region, NGC 281.
Bok hypothesized that giant molecular clouds, on the order of hundreds of light-years in size, can become perturbed and form small pockets where the dust and gas are highly concentrated.
The Bok globules in NGC 281 are located very close to the center of the IC 1590 cluster.
www.universetoday.com /am/publish/ngc_281_hubble.html?442006   (593 words)

  
 * Bok Globule - (Astronomy): Definition
In 1947, Bart Bok suggested that the small dark globules of interstellar gas and dust were undergoing collapse on their way to forming new stars.
Recent observations at radio wavelengths of a gas cloud known as Bok Globule B335 have produced images of material collapsing onto a newly born star (only about 150,000 years old).
The clouds, which are known as Bok globules after the astronomer who first described them, are so thick that they absorb the light from stars or gas clouds behind them.
en.mimi.hu /astronomy/bok_globule.html   (294 words)

  
 Bok, Derek (Curtis) - Hutchinson encyclopedia article about Bok, Derek (Curtis)   (Site not responding. Last check: 2007-10-20)
Bok taught labour and antitrust law at Harvard Law School, where he was also a reformist dean.
Bok's books include Beyond the Ivory Tower (1982) and Universities and the Future of America (1990).
This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.
encyclopedia.farlex.com /Bok%2c+Derek+(Curtis)   (104 words)

  
 H II region - Wikipedia, the free encyclopedia
Before then, the dense regions which contain the new stars are often seen in silhouette against the rest of the ionised nebula — these dark patches are known as Bok globules, after astronomer Bart Bok, who proposed in the 1940s that they might be stellar birthplaces.
Confirmation of Bok's hypothesis had to wait until 1990, when infrared observations finally penetrated the thick dust of Bok globules to reveal young stellar objects within.
It is now thought that a typical Bok globule contains about 10 solar masses of material in a region about a light year or so across, and that Bok globules most commonly result in the formation of double or multiple star systems
en.wikipedia.org /wiki/H_II_region   (2408 words)

  
 * Globule - (Astronomy): Definition
A globule is an interstellar cloud of dust and hydrogen gas that contracts and undergoes gravitational collapse to form a star.
Tiny globules of carbonates (minerals rich in carbon and oxygen) in the meteorite probably formed at temperatures below 200 degrees Fahrenheit, which makes it more likely they were produced by biological processes, according to a team led by John W. Found that some Bok globules contain protostars
Bok globules have characteristic radii of 103-105 AU.
en.mimi.hu /astronomy/globule.html   (496 words)

  
 ArcadeWater Web Search   (Site not responding. Last check: 2007-10-20)
Bok globules, named after astronomer Bart Bok who studied them extensively,..
An image of Bok globules in the, taken with the instrument on the..
A Bok globule is a dark cloud of dense dust and gas in which star formation is..
www.loans-in-cities.com /b/bok_globule.html   (184 words)

  
 [No title]   (Site not responding. Last check: 2007-10-20)
Globule poprvé nalezl v IC 2944 astronom A. Thackeray v roce 1950.
Globule se jeví jako těžce popraskané útvary,kterými projela velká vojska.
Takto možná by mohl vypadat zdroj ultrafialové radiace, hmotných hvězd, které také rozehřívají plyn v HII oblasti, což může mít za následek expanzní pohyb globulí a jejich destrukci.
astro.sci.muni.cz /pub/hst2002/prc02-01.html   (308 words)

  
 APOD: December 29, 1996 - Dark Bok Globules in IC 2944   (Site not responding. Last check: 2007-10-20)
Explanation: The dark spots in the above picture are not photographic defects but an unusual type of interstellar cloud known as a Bok globule.
Bok globules, named after astronomer Bart Bok who studied them extensively, are small dark clouds made of gas and dust that are typically condensing to form a star or stars.
These Bok globules are found in front of a glowing H II region known as IC 2944.
apod.gsfc.nasa.gov /apod/ap961229.html   (113 words)

  
 BBC - h2g2 - Four Types of Bok
Professor Bart Jan Bok (1906 - 1983) was a noted astronomer whose name has been immortalised with the Bok Globule.
The Bok Tower in central Florida is the centre piece of a large expanse of carefully sculpted gardens.
Bok choy is the American spelling of pak choi.
www.bbc.co.uk /dna/h2g2/A436321   (444 words)

  
 Astron. Astrophys. 350, 659-671 (1999)   (Site not responding. Last check: 2007-10-20)
Bok and Reilly 1947, Clemens and Barvainis 1988, Clemens et al.
In this scenario, the globule CB3 (Clemens and Barvainis 1988; LBN594), associated with the IRAS source 00259+5625, stands out for its distance (2500 pc according Launhardt and Henning 1997, while the average distance for Bok globules is around 600 pc) and for its high luminosity: 930
CO observations, concluding that CB3 is a candidate globule for collapse.
aa.springer.de /papers/9350002/2300659/sc1.htm   (476 words)

  
 Jahrbuch-CD der MPG 2003 - Active star formation in the la
A central concentration of reddened stars and a lower density halo of less reddened stars within the globule are revealed by JHK photometry.
A weak diffuse emission halo is detected in the near infrared with colours consistent with either scattered light or a ro-vibrational H-2 cascade.
This supports a scheme in which this Bok globule has formed independently rather than through dislocation from a nearby molecular cloud.
www.mpg.de /forschungsergebnisse/wissVeroeffentlichungen/archivListenJahrbuch/2002/21/publZIM62.html   (332 words)

  
 [20.22] Magnetic structure of a dark Bok globule   (Site not responding. Last check: 2007-10-20)
We have mapped the polarization and magnetic field of a dark Bok globule, within a radius of 66" centered on the dust peak.
The thermal dust continuum emission at 848 microns from the globule CB068, a Class-0 young stellar object (YSO), reveals strong linear polarization percentage values in two polarized-intensity regions located on both sides of the center, away from the twin CO outflows.
The two polarized regions are located on both sides of the axis of the twin CO outflows, with polarization contours paralleling the outflows.
www.aas.org /publications/baas/v34n4/aas201/1106.htm   (423 words)

  
 [No title]
Due to their relatively isolated location, Bok globules are well suited to study the direct interplay between protostellar collapse, fragmentation, and magnetic fields since they are less affected by strong turbulence and other nearby star-forming events.
The observations are not sensitive to the low-density material along the path length between the observer and the Bok globule.
The polarization maps of the Bok globules CB 26, CB 54, and DC 253-1.6 at 850 micron are shown in Figs.
www.jach.hawaii.edu /JCMT/publications/newsletter/n17/bok.html   (1178 words)

  
 Astron. Astrophys. 326, 329-346   (Site not responding. Last check: 2007-10-20)
Individual distances of the globules are derived with a method which associates the globules with larger molecular cloud complexes.
Using the detection rates and the relative frequencies of the globule groups, lifetimes of the different evolutionary stages are derived.
Assuming that all globules form stars at some time of their evolution, the typical lifetime of a Bok globule is derived to be some 10
aa.springer.de /bibs/7326001/2300329/small.htm   (385 words)

  
 bogol: bok globule!
a bok globule is a blob of glop in deap space.
The Bok crater on the Moon is named after him, as is the asteroid 1983 Bok.
There is a Bok crater on Mars as well, but it is named for a geographical location in Papua New Guinea and not after Mr.
bogol.blogspot.com /2005/02/bok-globule.html   (453 words)

  
 THE INFRARED UNIVERSE - Star Formation
Bok globules are also found in star forming regions.
In visible light, Bok globules are seen in dark silhouette against bright nebulae.
For example, Barnard 5 is a Bok globule that contains at least four protostars.
www.ipac.caltech.edu /Outreach/Edu/sform.html   (673 words)

  
 globule Globule: the Open-Source Content Distribution Network
Globule is a third-party module for the Apache Web server that allows a given server to replicate its documents to other Globule servers.
Cometary globule CG 4 Their energy is gradually destroying the dusty head of the globule, sweeping away tiny particles that scatter the starlight as a faint, bluish reflection nebula.
Globule Globule is a module for the Apache Web server that allows a given server to replicate its documents to other Globule servers.
trichosporon.host6.usaken.com /1141026384.html   (433 words)

  
 Astronomy For Kids - Nebulae - KidsAstronomy.com
A Bok Globule is different than the other types of clouds we have been learning about.
This means that there is a lot of dust and gas close together inside of the cloud.
In front of the reflection nebulae is a dark bok globule blocking the view.
www.kidsastronomy.com /nebulae.htm   (577 words)

  
 NationMaster - Encyclopedia: Wide Field and Planetary Camera 2
Triangulum is a small northern constellation whose three brightest stars, of third and fourth magnitude, form an elongated triangle.
Bok globules Download high resolution version (746x750, 90 KB)Bok globules in IC2944, as seen by the Hubble Space Telescopes WFPC2.
An image of Bok globules in the H II region IC 2944, taken with the WFPC2 instrument on the Hubble Space Telescope A Bok globule is a dark cloud of dense dust and gas in which star formation is taking place.
www.nationmaster.com /encyclopedia/Wide-Field-and-Planetary-Camera-2   (1549 words)

  
 Nebula NGC 1999
In this case, the source of illumination is the bright, young star V380 Orionis, which is visible just to the left of the center of the image.
The dark, "tilted T-shaped" cloud visible just to the right of the center of the image is a "Bok globule," which is a dense cloud of molecular gas and dust that may be forming new stars.
The Bok globule appears fl because it is so dense that it blocks almost all light from the background reflection nebula.
www.astrographics.com /GalleryPrintsIndex/GP0047.html   (260 words)

  
 Images of Our Galaxy   (Site not responding. Last check: 2007-10-20)
This dark cloud is an example of a "Bok globule," named after the late University of Arizona astronomer Bart Bok.
The globule is a cold cloud of gas, molecules, and cosmic dust, which is so dense it blocks all of the light behind it.
As the pillars themselves are slowly eroded away by the ultraviolet light, small globules of even denser gas buried within the pillars are uncovered.
www.cosmiclight.com /imagegalleries/ourgalaxy.htm   (5313 words)

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