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Orion Nebula binary star resolved by VLTI

... astronomers have plunged into the heart of the Orion Trapezium Cluster to produce the sharpest image ever obtained of the young double star Theta 1 Ori C...

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Hubble finds hidden exoplanet in archival data

...A powerful image processing technique may allow astronomers to seek out exoplanets that could be lurking in over a decade's worth of Hubble Space Telescope data...

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100 hours of astronomy

...Another great Cornerstone Project of the International Year of Astronomy kicks off this week with 100 hours of astronomy - the largest single science public outreach event ever organised...

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Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.


STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.


STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.


Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

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Hubble: You Decided Arp 274



Posted: 06 April, 2009

The Hubble Space Telescope imaged the winning target in the “You Decide” competition last week, revealing a triplet of galaxies called Arp 274 in unprecedented detail.

Arp 274, also known as NGC 5679, attracted 67,021 votes of the 140,000 that were cast towards six different galactic objects.

Hubble’s Wide Field Planetary Camera 2 was used to image Arp 274. Blue, visible, and infrared filters were combined with a filter that isolates hydrogen emission. The colours reflect the intrinsic colour of the different stellar populations. Image: NASA, ESA, M. Livio and the Hubble Heritage Team (STScI/AURA).

The first close-up view of the system revealed the galactic trio in striking detail. Previously thought to be a set of interacting galaxies, this may have been an optical illusion since there is no evidence for the galaxies becoming distorted due to gravitational forces.

The entire system resides at about 400 million light years away from Earth in the constellation Virgo, but the galaxies themselves may be separated by some distance.

Although they appear to be partially overlapping, the spiral shapes of the two largest galaxies appear mostly intact. The smallest galaxy, located on the far left, is the most compact, but shows evidence of star formation, betrayed by the bright blue knots of stars illuminating the galaxy.

Arp 274 in relation to nearby constellations. Image: NASA, ESA, and Z. Levay (STScI), A. Fujii for STScI.

The right hand galaxy also displays much evidence of star formation, with blue beads of star formation strung across the spiral arms along with pinkish nebulae that are illuminated by young stars. Interstellar dust is silhouetted against the starry population. Older, yellow stars form the main population of the galaxies’ central bulges, especially in the middle galaxy, which may have a central bar.

The release of this new image was part of the International Year of Astronomy's 100 Hours of Astronomy initiative, a global project aimed at encouraging as many people as possible to look at the night sky.