Hubble snaps stunning view of Thackeray's Globules
SPACE TELESCOPE SCIENCE INSTITUTE PHOTO RELEASE
Posted: January 3, 2002

Hubble
Thackeray's Globules in IC 2944. Photo: NASA and The Hubble Heritage Team (STScI/AURA); Acknowledgment: Bo Reipurth (University of Hawaii)
 
Strangely glowing dark clouds float serenely in this remarkable and beautiful image taken with NASA's Hubble Space Telescope. These dense, opaque dust clouds - known as "globules" - are silhouetted against nearby bright stars in the busy star-forming region, IC 2944. These globules were first found in IC 2944 by astronomer A.D. Thackeray in 1950.

Although globules like these have been known since Dutch-American astronomer Bart Bok first drew attention to such objects in 1947, little is still known about their origin and nature, except that they are generally associated with large hydrogen-emitting star-formation regions, called "HII regions" due to their glowing light of hydrogen gas.

The largest of the globules in this image is actually two separate clouds that gently overlap along our line of sight. Each cloud is nearly 1.4 light-years (50 arcseconds) along its longest dimension, and collectively, they contain enough material to equal over 15 solar masses. IC 2944, the surrounding HII region, is filled with gas and dust that is illuminated and heated by a loose cluster of O-type stars. These stars are much hotter and much more massive than our Sun. IC 2944 is relatively close by, located only 5900 light-years (1800 parsecs) away in the constellation Centaurus.

Thanks to the remarkable resolution offered by the Hubble Space Telescope, astronomers can for the first time study the intricate structure of these globules. The globules appear to be heavily fractured, as if major forces were tearing them apart. When radio astronomers observed the faint hiss of molecules within the globules, they realized that the globules are actually in constant, churning motion, moving supersonically among each other. This may be caused by the powerful ultraviolet radiation from the luminous, massive stars, which also heat up the gas in the HII region, causing it to expand and stream against the globules, leading to their destruction. Despite their serene appearance, the globules may actually be likened to clumps of butter put onto a red-hot pan.

Globules
Ground view of Globules in IC 2944. Photo: Copyright Anglo-Australian Observatory, Photograph by David Malin
 
It is likely that the globules are dense clumps of gas and dust that existed before the massive O-stars were born. But once these luminous stars began to irradiate and destroy their surroundings, the clumps became visible when their less dense surroundings were eroded away, thus exposing them to the full brunt of the ultraviolet radiation and the expanding HII region. The new images catch a glimpse of the process of destruction. Had the appearance of the luminous O-stars been a bit delayed, it is likely that the clumps would actually have collapsed to form several more low-mass stars like the Sun. Instead they are now being toasted and torn apart.

The hydrogen-emission image that clearly shows the outline of the dark globules was taken in February 1999 with Hubble's Wide Field Planetary Camera 2 (WFPC2) by Bo Reipurth (University of Hawaii) and collaborators. Additional broadband images that helped to establish the true color of the stars in the field were taken by the Hubble Heritage Team in February 2001. The composite result is a four-color image of the red, green, blue and H-alpha filters.

Women Astronauts
Learn about women astronauts,what they do, and how they got to where they are today. Read their story and how attitudes towards women in space changed.
 U.S. STORE
 WORLDWIDE STORE

Apollo 11 special patch
Special collectors' patch marking the 35th anniversary of the historic Apollo 11 moon landing is now available.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Inside Apollo mission control
An insider's view of how Apollo flight controllers operated and just what they faced when events were crucial.
 Choose your store:
U.S.

The ultimate Apollo 11 DVD
This exceptional chronicle of the historic Apollo 11 lunar landing mission features new digital transfers of film and television coverage unmatched by any other.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Next ISS crew
Own a little piece of history with this official patch for the International Space Station's Expedition 11 crew. We'll ship yours today!
 Choose your store:
U.S.

Apollo patches
The Apollo Patch Collection: Includes all 12 Apollo mission patches plus the Apollo Program Patch. Save over 20% off the Individual price.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Current Shuttle Mission Patch
The official embroidered patch for shuttle Endeavour's flight to finish building Japanese section of the space station.
 U.S. STORE
 WORLDWIDE STORE

Hubble Patch
The official embroidered patch for mission STS-125, the space shuttle's last planned service call to the Hubble Space Telescope, is available for purchase.
 U.S. STORE
 WORLDWIDE STORE

Ares Patch
The Ares Project will develop two new rockets to launch astronauts back to the Moon under NASA's Vision for Exploration. The Ares 1 will employ a single space shuttle solid rocket booster to loft the Orion crew capsule. The gigantic Ares 5 will haul the equipment and cargo needed for such lunar voyages. This is the Ares emblem.
 U.S. STORE




Project Orion
The Orion crew exploration vehicle is NASA's first new human spacecraft developed since the space shuttle a quarter-century earlier. The capsule is one of the key elements of returning astronauts to the Moon.
 U.S. STORE


Fallen Heroes Patch Collection
The official patches from Apollo 1, the shuttle Challenger and Columbia crews are available in the store.
 U.S. STORE
 WORLDWIDE STORE

Spaceflight Now Plus
The web's best space video service! Get additional video, audio, image and virtual reality content for a low-cost monthly or annual subscription fee. Subscriptions start at $5.95/£3.50. Click here to see what's currently available.
 SUBSCRIBE (U.S. Dollars)
 SUBSCRIBE (U.K. Pounds)

Hubble Posters
Stunning posters featuring images from the Hubble Space Telescope and world-renowned astrophotographer David Malin are now available from the Astronomy Now Store.
 U.S. STORE
 U.K. & WORLDWIDE STORE

Get e-mail updates
Sign up for our NewsAlert service and have the latest news in astronomy and space e-mailed direct to your desktop (privacy note: your e-mail address will not be used for any other purpose).
Enter your e-mail address:

INDEX | PLUS | NEWS ARCHIVE | LAUNCH SCHEDULE
ASTRONOMY NOW | STORE

ADVERTISE

© 2009 Spaceflight Now Inc.