Bok Globules

June 4, 2010
An optical image of a Bok globule, a dark cloud of gas and dust in which a young star is forming. A new paper reports on young stars forming inside these small clouds. Credit: Anglo-Australian Telescope

(PhysOrg.com) -- Bok globules are small interstellar clouds of very cold gas and dust that are so thick they are nearly totally opaque to visible light, although they can be studied with infrared and radio techniques. They were originally discovered as black splotches in front of dense fields of stars, and were even dubbed "holes in the heaven" because they appeared like holes in the stellar background.

Bok globules are typically less than 100 solar-masses in size, are relatively isolated, and often contain cores thought to be the embryos of new stars. It is this last feature that makes Bok globules particularly interesting to astronomers who want to use their relative simplicity to examine the very early stages of star formation under conditions much less confused than those in giant molecular cloud complexes like the . Moreover, the nearest Bok globules are as much as four times closer than the closest giant complexes, allowing more detailed observations.

CfA astronomer Tyler Bourke was part of an international team of nine scientists who studied thirty-two Bok globules with a suite of infrared, submillimeter, and millimeter telescopes, including the . They report in this month’s Supplement that warm cores were found in twenty-six of these globules, and eighteen of them could be approximately age dated based on their dust emission characteristics, and are from about one hundred thousand to two million years old.

Moreover, the team found that nearly two-thirds of these globules showed evidence of multiple stars, and in most of these cases the several stars appeared to be of different ages, with only three cases of coeval young . This latter result suggests that slow, sequential star formation is underway in these relatively isolated dark clouds.

Explore further: Hubble finds 'dust clouds' in Milky Way

Related Stories

Spitzer Reveals New Wonders in the Familiar Orion Nebula

August 15, 2006

The Orion nebula is one of the most famous and easily viewed deep-sky sights. Located in the sword of Orion the Hunter, this distant cloud of gas and dust holds hundreds of young stars. At its center, a cluster of four bright, ...

Birth of a star predicted

June 9, 2009

The astrophysicist João Alves, director of the Calar Alto Observatory in Almeria, and his colleague Andreas Bürkert, from the German observatory in the University of Munich, believe that "the inevitable future of the starless ...

Massive Stars Near the Galactic Center

August 28, 2009

The Central Molecular Zone (CMZ) of our galaxy is a giant complex of molecular gas and dust situated in the innermost 700 light-years of the Milky Way. Although the galaxy is over 100,000 light-years in size, nearly 10% of ...

Studying a Star Before it is Born

December 4, 2009

(PhysOrg.com) -- The first phase of a star's formation are thought to begin deep inside a natal cloud of gas and dust. In the earliest stages, material coalesces under the influence of gravity into so-called "dense cores," ...

Flaring Young Stars

January 4, 2010

(PhysOrg.com) -- The constellation of Vela (visible only from the southern hemisphere) contains a set of giant clouds of gas and dust known collectively as the Vela Molecular complex.

Recommended for you

Dense star clusters shown to be binary black hole factories

July 29, 2015

The coalescence of two black holes—a very violent and exotic event—is one of the most sought-after observations of modern astronomy. But, as these mergers emit no light of any kind, finding such elusive events has been ...

First detection of lithium from an exploding star

July 29, 2015

The chemical element lithium has been found for the first time in material ejected by a nova. Observations of Nova Centauri 2013 made using telescopes at ESO's La Silla Observatory, and near Santiago in Chile, help to explain ...

New names and insights at Ceres

July 29, 2015

Colorful new maps of Ceres, based on data from NASA's Dawn spacecraft, showcase a diverse topography, with height differences between crater bottoms and mountain peaks as great as 9 miles (15 kilometers).

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

TimESimmons
1 / 5 (2) Jun 05, 2010
Bok globule average density appears to decrease as total mass increases. Here's evidence for that and an explanation why:-

http://www.presto...ndex.htm

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.