Bok Globules

Jun 04, 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: Exomoons Could Be Abundant Sources Of Habitability

Related Stories

Birth of a star predicted

Jun 09, 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 ...

Spitzer Reveals New Wonders in the Familiar Orion Nebula

Aug 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 ...

Studying a Star Before it is Born

Dec 04, 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 ...

Flaring Young Stars

Jan 04, 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.

Massive Stars Near the Galactic Center

Aug 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, ...

Recommended for you

Big black holes can block new stars

10 hours ago

Massive black holes spewing out radio-frequency-emitting particles at near-light speed can block formation of new stars in aging galaxies, a study has found.

POLARBEAR seeks cosmic answers in microwave polarization

10 hours ago

An international team of physicists has measured a subtle characteristic in the polarization of the cosmic microwave background radiation that will allow them to map the large-scale structure of the universe, ...

New radio telescope ready to probe

13 hours ago

Whirring back and forth on a turning turret, the white, 40-foot dish evokes the aura of movies such as "Golden Eye" or "Contact," but the University of Arizona team of scientists and engineers that commissioned ...

Exomoons Could Be Abundant Sources Of Habitability

Oct 20, 2014

With about 4,000 planet candidates from the Kepler Space Telescope data to analyze so far, astronomers are busy trying to figure out questions about habitability. What size planet could host life? How far ...

Partial solar eclipse over the U.S. on Thursday, Oct. 23

Oct 17, 2014

People in most of the continental United States will be in the shadow of the Moon on Thursday afternoon, Oct. 23, as a partial solar eclipse sweeps across the Earth. For people looking through sun-safe filters, from Los Angeles, ...

User comments : 1

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