Astronomers report mysterious giant star clusters

January 10, 2006
Astronomers report mysterious giant star clusters
Super star clusters and super nebulae in the nearby galaxy NGC 4214. A Keck Telescope infrared image is superimposed on a Hubble Space Telescope image, with visible star clusters shown in blue. The black dots, revealed in radiographs, are young super star clusters in the process of forming.

An international team of astronomers reported evidence for the formation of mysterious "super star clusters" Jan. 9 at the annual meeting of the American Astronomical Society in Washington, D.C. These star clusters are the likely precursors to the familiar globular clusters of the Milky Way; however in our galaxy, globular clusters are all believed to be older than 10 billion years -- close to the age of the universe itself -- and none are forming.

Using the Very Large Array Telescope, the astronomers detected radio-infrared "super nebulae" around giant star clusters in the process of formation in a dozen nearby galaxies.

"The super nebulae are gas clouds heated by intense ultraviolet light from young super star clusters," said Chao-Wei Tsai, UCLA astronomy graduate student and leader of the team. "The star clusters are young and still hidden within their birth clouds. Although we cannot see the clusters directly, we can clearly detect the infrared and radio emissions from the hot gas surrounding them."

"The super star clusters hidden within these super nebulae are probably a lot like globular clusters in our own Milky Way, only younger, and they can contain up to a million young stars," said Jean Turner, UCLA professor of physics and astronomy, and a member of the team, along with Sara C. Beck of Tel Aviv University. "The mystery is why our own Milky Way no longer forms globular star clusters and hasn't for 10 billion years. These galaxies still can. We want to know why. This is star formation on steroids."

Super star clusters pack a huge number of bright and blue stars into a very small volume of space, with a density of stars up to a million times higher than near the sun. The radiant power emitted by these clusters can be up to a billion times the sun's wattage, in a region only a few light years across.

"The brightest of even one of these stars at the distance of the sun could charge a solar powered car in one second with enough energy to drive from Los Angeles to San Francisco!" Turner said.

The researchers obtained their radio and infrared images of the super nebulae using the Very Large Array of the National Radio Astronomy Observatory, a facility of the National Science Foundation, and the W. M. Keck Observatory in Hawaii, operated jointly by the University of California and the California Institute of Technology, with support from NASA.

The discovery of young super nebulae around these potential proto-globular clusters was made by a team led by Beck and Turner several years ago. This latest result shows just how common young super clusters outside the Milky Way are.

"Life on a planet orbiting a star in a young super star cluster would be very different," mused Beck. "There would be light coming from every direction, and no darkness or night -- sunlight would be very blue -- it would be a strange place to live."

Source: University of California - Los Angeles

Explore further: How the universe's brightest galaxies were born

Related Stories

How the universe's brightest galaxies were born

September 23, 2015

The brightest galaxies in our universe are fuelled by what their gravity sucks in, not through explosive mergers of star systems as scientists previously argued, researchers said Wednesday.

Launch of Astrosat first Indian astronomy satellite

September 28, 2015

The first Indian astronomy satellite Astrosat was launched on 28th September, 2015, by the Indian Space Research Organisation (ISRO) from Sriharikota, on a PSLV (Polar Satellite Launch Vehicle) rocket. Astrosat has unprecedented ...

The turbulent birth of super star clusters in galaxy mergers

February 10, 2012

By combining two of the most advanced telescopes in the world -- the new Atacama Large Millimeter Array (ALMA) and the Very Large Telescope (VLT) of ESO -- a team of French astronomers from the Institut d'astrophysique spatiale ...

Recommended for you

Amazon deforestation leaps 16 percent in 2015

November 28, 2015

Illegal logging and clearing of Brazil's Amazon rainforest increased 16 percent in the last year, the government said, in a setback to the aim of stopping destruction of the world's greatest forest by 2030.

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...


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.