Category: Hubble

This latest image released from the Hubble Space Telescope shows the dwarf galaxy NGC 4449, located about 12.5 million light-years away. Although the galaxy has been around for billions of years, it recently went through a period of intense star formation.

Most starburst galaxies concentrate their stellar formation around the crowded galactic core, but in NGC 4449, the active regions extend out across more of the galaxy. This will only last for another billion years or so, when the gas supply that feeds the star forming regions runs out. It will then stay quiet until it has a close encounter with another galaxy, starting the process all over again.

A galaxy like NGC 4449 resembles what the first primordial galaxies probably looked like, formed shortly after the Big Bang when the Universe was young. Many small galaxies merged together forming larger and larger galaxies until they became the majestic spirals we see today. Each new merger brings in a fresh supply of raw materials as well as the gravitational interactions to force gas clouds to collapse.

Original Source:Hubble

Kaboom kaboom. That’s what an international team of astronomers saw when they tracked the death of one of the most massive stars that can exist.

Japanese supernova hunter, Koichi Itagaki, first discovered an exploding star in the galaxy UGC4904 back in 2004. It flared briefly and then faded away over the course of 10 days. Two years later, he discovered another supernova in exactly the same location.

Subsequent observations with larger telescopes confirmed that the supernova, named SN2006jc, did indeed happen at exactly the same location as the previous detonation. The 2004 event must have just been a large outburst, similar to what was seen on Eta-Carinae back in the 1850s.

The researchers think this kind of event could actually be more common than previously believed. A new survey called Pan-STARRS may check up on previous supernova events to see if there’s any new activity.

Original Source: Queen’s University Belfast News Release

Astronomers released this beautiful photograph of the grand spiral design galaxy, M81, captured by the Hubble Space Telescope. Although it looks like a single image, it was actually constructed by stitching together many images on computer, using three different wavelengths of light.

M81 is located about 11.6 million light-years in the constellation of Ursa Major. We’re fortunate that it’s turned at an oblique angle towards the Earth, so we can see a full view of the spiral structure. Hubble’s view of M81 is so crisp and clear that individual stars can be resolved, as well as open clusters and globular star clusters.

The older, redder stars are contained around the galaxy’s central bulge, and it has regions of star formation along its spiral arms. Astronomers suspect that its recent nearby encounter with another galaxy (M82) unleashed the period of star formation about 300 million years ago.

The image was released as part of the Americal Astronomical Society Meeting in Honolulu, which is currently going on in Hawaii.

Original Source: Hubble News Release

Astronomers have long believed that globular star clusters formed out of a single cloud of dust and gas. All the stars in the cluster should be roughly the same age. But new observations from the Hubble Space Telescope show this isn’t always the case – in cluster NGC 2808, there were three distinct periods of star formation.

Globular star clusters are some of the most ancient objects in the Universe, forming shortly after their parent galaxies came together. They’re compact swarms with hundreds of thousands of stars held together by mutual gravity. The traditional view is that these clusters formed together, from the same material, at the same time, and then evolved together over time.

These new Hubble observations show that there are clearly three different populations of stars in globular cluster NGC 2808. All of the stars formed within 200 million years of each other. Each generation contains a different mix of chemicals, with increasing quantities of helium.

One theory is that the clusters hung onto large quantities of gas, beyond that initial period of star formation. Some event, or shockwaves from supernovae might have collapsed this gas, mixing in heavier elements to create additional stars. Another possibility is that NGC 2808 isn’t a globular cluster at all, but an ancient dwarf galaxy that was stripped of most of its material when it was captured by the Milky Way.

Original Source: Hubble News Release