ESO ALMA: Supernova 1987A's super dust factory

This is a composite image of supernova 1987A. 

ALMA data (in red) shows newly formed dust in the center of the remnant. 

HST (in green) and Chandra (in blue) show the expanding shockwave. 

Credit: Alexandra Angelich (NRAO/AUI/NSF); NASA Hubble; NASA Chandra

Galaxies can be remarkably dusty places and supernovas are thought to be a primary source of that dust, especially in the early Universe.

Direct evidence of a supernova's dust-making capabilities, however, has been slim and cannot account for the copious amount of dust detected in young, distant galaxies.

Striking new observations with the ESO Atacama Large Millimeter/submillimeter Array (ALMA) telescope capture, for the first time, the remains of a recent supernova brimming with freshly formed dust.

If enough of this dust makes the perilous transition into interstellar space, it could explain how many galaxies acquired their dusty, dusky appearance.

Remy Indebetouw

"We have found a remarkably large dust mass concentrated in the central part of the ejecta from a relatively young and nearby supernova," said Remy Indebetouw, an astronomer with the National Radio Astronomy Observatory (NRAO) and the University of Virginia, both in Charlottesville.

"This is the first time we've been able to really image where the dust has formed, which is important in understanding the evolution of galaxies."

The results are being reported at the January meeting of the American Astronomical Society (AAS). They also are accepted for publication in the Astrophysical Journal Letters.

An international team of astronomers used ALMA to observe the glowing remains of supernova 1987A, which is in the Large Magellanic Cloud, a dwarf galaxy orbiting the Milky Way approximately 168,000 light-years from Earth.

Light from this supernova arrived at Earth in 1987, inspiring its name. This makes 1987A the closest observed supernova explosion since Johannes Kepler's observation of a supernova inside the Milky Way in 1604.

This artist's illustration of supernova 1987A reveals the cold, inner regions of the exploded star's remnants (in red) where tremendous amounts of dust were detected and imaged by ALMA.

This inner region is contrasted with the outer shell (lacy white and blue circles), where the energy from the supernova is colliding with the envelope of gas ejected from the star prior to its powerful detonation. 

Credit: Alexandra Angelich (NRAO/AUI/NSF)

Astronomers predicted that as the gas cooled after the explosion, large amounts of molecules and dust would form as atoms of oxygen, carbon, and silicon bonded together in the cold central regions of the remnant.

However, earlier observations of 1987A with infrared telescopes, made within the first 500 days after the explosion, detected only a small amount hot dust.

With ALMA's unprecedented resolution and sensitivity, the research team was able to image the far more abundant cold dust, which glows brightly in millimeter and submillimeter light.

The astronomers estimate that the remnant now contains about 25 percent the mass of our Sun in newly formed dust. They also found that significant amounts of carbon monoxide and silicon monoxide have formed.

More information: J. Kamenetzky et al. 2013 ApJ 773 L34. doi:10.1088/2041-8205/773/2/L34

ESO ALMA Giant Radio Telescope Reaches Full Power with 66 Antennas

The Atacama Large Millimeter/submillimeter Array (ALMA) consists of 66 antennas and is located in the Atacama Desert of northern Chile. 

North America and Asia each provided 25 and East Asia gave 16. They will helps answer cosmic origin questions.

Credit: ESO/M. Marchesi

The antenna was delivered Monday (Sept. 30) to the Atacama Large Millimeter/submillimeter Array (ALMA), and is expected to be installed by the end of the year. ALMA has been in operation for years, adding antennas as it goes.

With this last antenna one — No. 66 of the dozens provided by Europe, North America and Asia — the telescope will reach its maximum sensitivity.

Phil Jewell

"This is an important milestone in a project that has already expanded our understanding of the universe," Phil Jewell, the North American ALMA project director, said in a statement.

"Since the delivery of the first antenna in 2009, ALMA has enabled unprecedented research and made startling discoveries. The international scientific community eagerly awaits the new capabilities ALMA will provide now that it is reaching its full potential."

The giant ALMA radio telescope officially opened for business in March, when all major systems were put online and the heaviest phase of construction finished.

When complete, the radio telescope array will stretch across nearly 10 miles (16 kilometers) of Chile's Atacama Desert.

The $1.3 billion ALMA telescope is over seen by the European Southern Observatory and is by far the largest instrument capable of making observations in the submillimeter wavelength.

Submillimeter astronomy uses wavelengths that are longer than radio waves, but shorter than visible light. It allows astronomers to peer through dust to see stars and planets being born, among other phenomena.

ALMA's huge antennas pick up sky signals individually. A supercomputer then combines their observations and calculates the signals' direction, similar to how humans use their two ears to pinpoint the location of the sound.