Tag Archives: star cluster

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Universe at your fingertips – 3D prints of Hubble photos let the blind ‘see’

NGC 609 is one of the many small galactic star clusters located in the Milky Way in Cassiopia. It shines at magnitude 11.0, is 4 arc minutes in diameter and contains over 100 stars. Photo: Hubble telescope.

NGC 609 is one of the many small galactic star clusters located in the Milky Way in Cassiopia. It shines at magnitude 11.0, is 4 arc minutes in diameter and contains over 100 stars. Photo: Hubble telescope.

Captioned above is one of Hubble‘s most famous and beautiful space photos. The photo features NGC 609 – a magnificent star cluster, which Hubble captured complete with colored gas, dust and a slew of stars of various brightness. Pictures like these remind people of the tremendous gift they have – sight. How can one share and hope to convey a fraction of the stunning beauty one experiences when looking at pictures like NGC 609 to those less fortunate, deprived of sight?

The full valor of visual beauty may never be reproduced to the blind (one can imagine however relaying electrical signals through an EEG directly to the brain, creating an accurate mental picture. this is SciFi at the moment, however), nevertheless some scientists are trying their best. A team of astronomers and computer engineers at the Space Telescope Science Institute in Baltimore, Md have made 3D printed models of NGC 609, specially designed so the blind can have a mental picture of how the star cluster looks like using their sense of touch.

ngc-star-cluster-for-blind

Some 100 volunteers aged 8 to 81 were asked to give feedback, and eventually a rather accurate tactile model was made. Made of plastic, the models includes features like stars, gas and dust differentiated not by color or other visual cues, but through texture. The varying heights of the features correspond to varying levels of brightness.

“We found we were able to create mental models for these people,” astronomer Carol Christian says. “They would say, ‘I can see it, I can see it,’ and then they would describe what they were seeing in their head.”

Still, these model are representations of flat, 2-D images. A fantastic upgrade would be making a 3D spherical model of NGC 609, if the various technical and artistic challenges are overcome.

“Our ultimate goal is for anyone who would like to hold a piece of the universe in their hands, can get the data files that we will process from the Hubble archive, and they can print them at home, at school, or in a library,” Christian says.

Billions of glowing stars from the brightest part of the Milky Way have been imaged this photo. At it's center lies a contrasting pair - a star cluster and a dark nebula. (c) ESO

Milky Way’s brightest star patch imaged [FANTASTIC ASTROPHOTO]

A telescope in Chile recently imaged one of the brightest spots at the core of the Milky Way, beautifully illustrating a star cluster and its neighboring dark nebula. The latter offers a stunning contrast for the billions of stars present in this patch of our galaxy.

Billions of glowing stars from the brightest part of the Milky Way have been imaged this photo. At it's center lies a contrasting pair - a star cluster and a dark nebula. (c) ESO

Billions of glowing stars from the brightest part of the Milky Way have been imaged this photo. At it’s center lies a contrasting pair – a star cluster and a dark nebula. (c) ESO

This fantastic view was made possible using the Wide Field Imager from ESO’s La Silla Observatory in Chile. This particular patch is called the  the Large Sagittarius Star Cloud, located in the the constellation of Sagittarius (The Archer), and is one of the  richest star fields in the whole sky.

A small, isolated dark area, described as “a drop of ink on the luminous sky” by U.S. astronomer Edward Emerson Barnard, who discovered it in 1913, sits in the middle of the image. This is a dark nebula called Barnard 86, that’s made out of small dust grains that scatter and block starlight, letting the region appear opaque.

The brightest object in the photo is actually a star cluster – a group of gravitationally bound stars that can be by the thousands in number- called NGC 6520.

Hubble takes brilliant picture of young star population in elderly company

The great pics from Hubble just never end! This time, the brave telescope offered an impressive view of the center of globular cluster NGC 6362. The image of this spherical collection of stars takes a deeper look at the core of the globular cluster, which contains a high concentration of stars with different colors.

Click the pic for full size.

Seeing what appears to be young stars came as quite a surprise, considering that globular clusters are composed of old stars, which, at around 10 billion years old, are way older than the Sun. These clusters are quite common both in our galaxy (over 150 found so far) and in other galaxies. Also, globular clusters are among the oldest objects directly observable in the known Universe, making them living fossils, extremely useful in understanding how galaxies work.

The accepted theory at the moment is that all stars in a globular cluster are about the same age; however, new, high precision measurements performed in numerous globular clusters, primarily with the Hubble Space Telescope have made some astrophysicists doubt this theory. In particular, there appear to be younger, bluer stars, amidst older ones. Researchers dubbed them blue stragglers and NGC 6362 has lots of them.

It’s unclear at the moment how they appear, but since they are usually found in the core regions of clusters, where the concentration of stars is large, the most plausible explanation seems to be that they form as a result of stellar collisions or transfer of material between stars in binary systems.

NGC 6362 is located about 25 000 light-years from Earth in the constellation of Ara (The Altar), and it was discovered all the way back in 1826 by British astronomer James Dunlop.

An artist's conception of a black hole in globular cluster. (c) NRAO/AUI/NSF

Black hole pair in star cluster defy scientific expectations

Black holes are simply the worst neighbors to have around, as they wreck havoc in their vicinity. Scientific belief states, however, that in a globular cluster, which is a massive spherical conglomeration of thousands of thousands of stars, you can’t have more than one black hole, if any. New findings however show that there’s no safe neighborhood, as data suggests black holes may reside in pairs in star clusters.

“Before this work, there were zero black holes known in Milky Way globular clusters, so even finding one would have been exciting,” said lead study author Jay Strader, an astronomer at Michigan State University in East Lansing.

An artist's conception of a black hole in globular cluster. (c) NRAO/AUI/NSF

An artist’s conception of a black hole in globular cluster. (c) NRAO/AUI/NSF

Initially, the researchers used the recently upgraded Very Large Array (VLA), a network of radio dishes near Socorro, N.M., to look for an intermediate-mass black hole at the center of M22, a globular cluster 10,000 light years away. Now, although they didn’t find the central black hole they were after in the first place, they stumbled across something a whole lot more valuable. Intermediate-mass black holes have a mass of around a few thousand times that of our sun. Supermassive blackholes, commonly found at the center of galaxies, weigh millions to billions times the mass of our sun. In M22 the astronomers found a pair of even lighter black holes that form from the collapse of massive stars – each are only 10 to 20 times the mass of the sun.

These black holes are both binary systems, each possessing a companion star from which they are ripping matter from like a vampire. Matter from the stars, like gas and dust, is drained and collected by the black hole, much like water swirling down a drain.

“One of the most interesting aspects of this work is that we found the black holes via radio emission,” Strader said. “All the other stellar-mass black holes in our galaxy have been discovered by X-ray emission rather than radio. We hypothesize that the reason our sources haven’t been seen in previous X-ray searches is that they aren’t accreting very much matter at all, so they don’t produce the hot accretion disks that glow in the optical and X-rays.

Theories say that that there may be few or no black holes in a globular cluster, as gravitational interactions between black holes in the cluster would eject almost all the black holes in short order. The two black holes, named M22-VLA1 and M22-VLA2, provide counter evidence to these theories. Strader and colleagues estimate that there could be as many as 100 low-mass black holes in the globular cluster.

“Future computer simulations of the evolution of globular clusters with populations of black holes should help address this issue,” Strader said.

He added, “My personal view is that it’s likely that other clusters also have black holes that we just haven’t found yet.”

The astronomers from the U.S., England and Australia announced their discovery in a study published in the October 4 issue of Nature.

An artist impression of one of the two gas giants discovered orbiting a sun-like star, part of a star cluster. (c) NASA/JPL-Caltech

First evidence of planet formation around sun-like stars in clusters

An artist impression of one of the two gas giants discovered orbiting a sun-like star, part of a star cluster. (c) NASA/JPL-Caltech

An artist impression of one of the two gas giants discovered orbiting a sun-like star, part of a star cluster. (c) NASA/JPL-Caltech

Astronomers, financially backed by NASA, have for the first time ever discovered tantilizing evidence that planets can form and exist around sun-like stars, densly packed together in star clusters. The finding is of significant importance, as scientists claim that it shows that planet can indeed exist in extremely harsh environments, like star clusters.

The two planets, Pr0201b and Pr0211b, were discovered each circling their own sun-like star in the Beehive Cluster, also known as the Praesepe – a cluster containing more than 1000 stars very close to one another which orbit around a center. The planets, discovered and analyzed by the 1.5-meter Tillinghast telescope located at the Smithsonian Astrophysical Observatory’s Fred Lawrence Whipple Observatory near Amado, Arizona, are not habitable – far from it.

The planets are in class called Hot Jupiters, massive gas giants with boiling hot environments, because of a very tight orbit.

“We are detecting more and more planets that can thrive in diverse and extreme environments like these nearby clusters,” says Mario R Perez, NASA astrophysics program scientist in the Origins of Solar Systems Program.

“Our galaxy contains more than 1,000 of these open clusters, which potentially can present the physical conditions for harboring many more of these giant planets.”

These aren’t the first planets discovered orbiting around stars in a cluster, however they’re the first to be found orbiting around stars similar to our sun. The astronomers involved in the study hope this latest discovery might help answer how hot Jupiters wind up so close to their stars. Also, it offers proof that planets can form in harsh environments.

“This has been a big puzzle for planet hunters,” says Sam Quinn, a graduate student in astronomy at Georgia State University.

“We know that most stars form in clustered environments like the Orion nebula, so unless this dense environment inhibits planet formation, at least some sun-like stars in open clusters should have planets. Now, we finally know they are indeed there.”

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Celestial fireworks from dying stars

A new image of the nebula NGC 3582, which was captured by the Wide Field Imager on the MPG/ESO 2.2-metre telescop at ESO’s La Silla Observatory in Chile shows giant loops of gas that resemble what you would see for New Year’s Eve; however, there probably isn’t much joy in that sector, as these loops are believed to be emitted by dying stars. What’s interesting is that new stars are also being born in the same area, so this makes it a stellar nursery, as well as a stellar cemetery.

NGC 3582 is part of a large star-forming region in the Milky Way, called RCW 57 which is close to the constellation of Carina. Stars born in that sector are typically much larger and heavier than the Sun, and these giants emit radiation at incredible rates, which is why we get to see this magnificent display of colour, but it’s also the reason why they have such short lived and explosive lives.

The image was processed by ESO using the observational data identified by Joe DePasquale, from the United States, who participated in ESO’s Hidden Treasures 2010 astrophotography competition.

We now know the birth place of the biggest guitar in the galaxy

guitarIn case you’re wondering, the biggest ‘guitar’ in our galaxy is in fact a pulsar that was nicknamed The Guitar Pulsar. It’s basically a stellar corpse that emits a beam of electromagnetic radiation that just shreds interstellar gas, creating a wake of hot hydrogen shaped just like a guitar.

Little is known about these remnants, from any point of view. In order to track down it’s birthplace, Nina Tetzlaff at the University of Jena in Germany and her colleagues calculated the location of 140 groups of stars, as they were 5 millions ago.

The pulsar was practically launched from a cluster of massive stars, moving at about 1500 kilometres per second, which is just huge. They were able to pinpoint the exact location it was formed, but why it moved so fast still remains a mystery. Speeds over 1000 km/s are practically not used in current astronomy models, and are considered by many to be borderline impossible.

A Colourful Cosmic Jewel Box

A Snapshot of the Jewel Box cluster with the ESO VLT

A Snapshot of the Jewel Box cluster with the ESO VLT

Star clusters are among the pretties things you can see, when it comes to astrophysical observations. Recently, ESO provided some amazing pictures of one of the most beautiful nestles ever to be seen, located deep in the constellation of Crux.

Wide Field Image of the Jewel Box

Wide Field Image of the Jewel Box

The cluster is named Kappa Crucis Cluster and has been nicknamed ‘the jewel box’ (by Herschel, in 1830), for reasons easy to understand – it’s bright enough to be seen even with the naked eye.

Such open clusters can have from a few to thousands of stars that are loosely bound together by their own combined gravity. They’re really important for studies, because they were formed from the same cloud of gas (which means they have pretty much the same age and chemistry).

A Hubble gem: the Jewel Box

A Hubble gem: the Jewel Box

The FORS1 instrument on the ESO Very Large Telescope means we can look at this cluster in a whole different way, at extreme image quality.

Despite the chemical and age resemblance, stars in the cluster are extremely varied; there are pale blue supergiant stars, a solitary ruby-red supergiant and numerous brightly colored stars, as well as some that are more faint.

Digitized Sky Survey 2 Image of NGC 4755

Digitized Sky Survey 2 Image of NGC 4755

The huge variety in colors results from the mass difference: there are stars that are smaller than half of the Sun, while some are 20 times bigger than our star