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Posts Tagged ‘Astronomers’

NASA discovered the oldest galaxy

An international team of astronomers appointed to do research on the space has found the oldest galaxy which seems to exist before 13.2 billion years ago. They discovered this galaxy with the help of Hubble Space Telescope. They marked the existed galaxy and enlarged it to obtain a clear view. Astronomers found that the galaxy [...]

High-resolution images of dying giant star captured


An international team of astronomers has made the most high-resolution images of a dying giant star to date. 

Led by Keiichi Ohnaka at the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, the astronomers, for the first time showed how the gas is moving in different areas over the surface of a distant star known as Betelgeuse. 

This was made possible by combining three 1.8 metre telescopes as an interferometer, giving the astronomers the resolving power of a virtual, gigantic 48-metre telescope. 

Using the ESO VLT Interferometer in Chile, they discovered that the gas in the dying star’s atmosphere is vigorously moving up and down, but the size of such “convection cell or bubble” is as large as the star itself. 
 

These colossal bubbles are a key for pushing material out of the star’s atmosphere into space, before the star explodes as a supernova. 

Betelgeuse is a so-called red supergiant and approaching the end of its short life of several million years. 

Red supergiants shed a large amount of material made of various molecules and dust, which are recycled for the next generation of stars and planets possibly like the Earth. 

Betelgeuse is losing material equivalent to the Earth’s mass every year. 

“Our AMBER observations mark the sharpest images ever made of Betelgeuse”, said Keiichi Ohnaka at the MPIfR. 

“And for the first time, we have spatially resolved the gas motion in the atmosphere of a star other than the Sun. Thus, we could observe how the gas is moving in different areas over the star’s surface,” he added. 

The AMBER observations have revealed that the gas in Betelgeuse’s atmosphere is moving vigorously up and down. 

The size of these “bubbles” is also gigantic, as large as the supergiant star itself. 

While the origin of these bubbles is not yet entirely clear, the AMBER observations have shed new light on the question about how red supergiant stars lose mass: such colossal bubbles can expel the material from the surface of the star into space. 

It also means that the material is not spilling out in a quiet, ordered fashion, but is flung out more violently in arcs or clumps. 

The death of the gigantic star, which is expected in the next few thousand to hundred thousand years, will be accompanied by cosmic fireworks known as a supernova like the famous SN1987A.

Amazing footage of lunar probe's final moments before it crashes into Moon

Footage showing the dramatic descent of a probe minutes before it crashes into the surface of the Moon has been released by the Japanese space agency.

The final moments of the Kaguya lunar probe were caught by its on-board high-definition camera as it hurtled downwards on June 11 and as it fell the images were beamed back to Earth 

As it sinks lower and lower the desolate and pockmarked landscape is seen looming ever larger as the spacecraft tumbles toward its final resting place.

This is one of the final images taken by the probe before it hits the Moon, revealing its pock-marked surface

The white spot in the centre of the far left image shows the impact made by the probe. In the images centre and right it gradually fades from view

 
 

This artist’s impression shows the Kaguya orbiting the moon

Long shadows are visible on the surface because the probe landed on the near side of the Moon in an area where the Sun had just set.

Unfortunately at the end of the sequence the film blacks out because the probe entered a ‘shaded’ area where there was no sunlight and as a result its impact was not recorded.

However, its disappearance was picked up back on Earth by astronomers Jeremy Bailey and Steve Lee using the Anglo-Australian Telescope in New South Wales, Australia. The probe caused a flash of light as it exploded on impact and this light was seen fading away.

The ‘controlled crash’ completed the Kaguya’s Moon observation mission, which was launched two years ago on September 14 and cost £353million.

In that time the 3 ton probe which measured 2.1m long and 4.8m wide, carried out a survey of the moon and mapped its topography and magnetic field. Furthermore, a month after its launch it jettisoned two 110lb ‘baby’ satellites to create a map detailing gravitational forces.

Astonishingly, it was powered by just 3.5kW, which is equivalent to the energy used by two standard hairdryers.

Another of the probe’s final images before it landed on the near side of the Moon

On April 5, 2008, Kaguya captured a sequence of images showing the Earth rise above the Moon’s horizon

During the mission is also took clear videos of the lunar surface, breath-taking views of the Earth appearing on the horizon as the probe skims across the surface. In another stunning sequence it captures the Earth eclipsing the Sun. At first all that can be seen is blackness but then suddenly a halo appears as the Earth moves away to reveal the Sun.

Researchers hope that the data it has collected on this mission could shed further light on the Moon’s origin and evolution.

The planet remains under close scrutiny as India’s Chandrayaan 1 orbiter, launched in October last year, continues to circle it.

 
 Nasa’s Lunar Reconnaissance Orbiter reached its orbit around the Moon today

This month Nasa launched two Moon missions of its own to find potential landing sites for human exploration. One of them is the Lunar Reconnaissance Orbiter (LRO), which today successfully entered orbit around the Moon following a five-day journey. In four days’ time it will finalise its initial orbit.

Its job will be to explore the moon’s craters, examining sunlit and shadowed regions, and provide understanding of the effects of lunar radiation on people. Part of its mission will be to build up three-dimensional maps of the lunar surface.

The other mission is the Lunar Crater Observation and Sensing Satellite (LCROSS), which separated from LRO soon after they launched together. LCROSS is taking a separate path to the Moon and will split into two parts once in orbit. 

The first part will hit the moon near the South Pole and make a crater around a third the size of a football pitch. The second part will fly through the dust and ice raised by the impact and study them before landing several miles away.

Watch the last moments of the Japanese probe…

Watch a spectacular Earth rise observed the Kaguya probe…

Unseen Dark Comets 'Could Pose Deadly Threat To Earth'

‘Dark’ comets happen when the water on their surface has evaporated,
causing them to reflect less light Photo: GETTY

From The Telegraph:

Unseen “dark” comets could pose a deadly threat to earth, astronomers have warned.

The comets, of which there could be thousands, are not currently monitored by observatories and space agencies.

Most comets and asteroids are monitored in case they start to travel towards earth.

But Bill Napier, from Cardiff University, said that many could be going by unnoticed.

“There is a case to be made that dark, dormant comets are a significant but largely unseen hazard,” he said

Scientists estimate that there should be around 3,000 comets in the solar system, but only 25 have so far been identified.

“Dark” comets happen when the water on their surface has evaporated, causing them to reflect less light.

Read more ….

Top 5 Most Extreme Exoplanets


From Wired Science:

Searching for planets beyond our solar system is a bit like playing Goldilocks — we keep looking for that one that will be just right to host life. While astronomers haven’t found a perfect fit yet, they have found plenty that are too big, too hot, too cold, too dense, too close to their star, or too distant.

The first exoplanet discovery was in 1988, though it was controversial at the time and wasn’t officially confirmed until 2003. Over the years, more than 330 extrasolar planets have been found, nearly all of them using indirect methods such as detecting the wobble of a star due to the gravitational pull of an orbiting planet or the slight dimming of the star’s light as a planet passes in front of it.

Read more ….

Super-Neptune Planet Found

This artist’s conception reveals the newly discovered Super-Neptune planet orbiting a star 120 light years away from Earth. Normally blue in color, its red hue is caused by the illumination from the nearby Red Dwarf star. Credit: David A. Aguilar (CfA)

Astronomers have discovered a planet somewhat larger and more massive than Neptune orbiting a star 120 light-years from Earth. 

While Neptune has a diameter 3.8 times that of Earth and a mass 17 times Earth’s, the new world (named HAT-P-11b) is 4.7 times the size of Earth and has 25 Earth masses.

HAT-P-11b was discovered because it passes directly in front of its parent star, thereby blocking about 0.4 percent of the star’s light. This periodic dimming, called a transit, was detected by a network of small, automated telescopes known as “HATNet,” which is operated by the Harvard-Smithsonian Center for Astrophysics in Arizona and Hawaii. 

More than 300 extrasolar planets are now known to exist.

HAT-P-11b is the 11th extrasolar planet found by HATNet, and the smallest yet discovered by any of the several transit search projects underway around the world.

Transit detections are particularly useful because the amount of dimming tells the astronomers how big the planet must be. By combining transit data with measurements of the star’s “wobble” (radial velocity) made by large telescopes like Keck, astronomers can determine the mass of the planet.

A number of Neptune-like planets have been found recently by radial velocity searches, but HAT-P-11b is only the second Neptune-like planet found to transit its star, thus permitting the precise determination of its mass and radius.

The newfound world orbits very close to its star, revolving once every 4.88 days. As a result, it is baked to a temperature of around 1100 degrees F. The star itself is about three-fourths the size of our Sun and somewhat cooler.

There are signs of a second planet in the HAT-P-11 system, but more radial velocity data are needed to confirm that and determine its properties.

Another team has located one other transiting super-Neptune, known as GJ436b, around a different star. It was discovered by a radial velocity search and later found to have transits.

“Having two such objects to compare helps astronomers to test theories of planetary structure and formation,” said Harvard astronomer Gaspar Bakos, who led the discovery team.

HAT-P-11 is in the constellation Cygnus, which puts in it the field of view of NASA’s upcoming Kepler spacecraft. Kepler will search for extrasolar planets using the same transit technique pioneered by ground-based telescopes. This mission potentially could detect the first Earth-like world orbiting a distant star. “In addition, however, we expect Kepler to measure the detailed properties of HAT-P-11 with the extraordinary precision possible only from space,” said Robert Noyes, another member of the discovery team.

Hubble Captures Outstanding Views Of Mammoth Stars


From E! Science News:

The image shows a pair of colossal stars, WR 25 and Tr16-244, located within the open cluster Trumpler 16. This cluster is embedded within the Carina Nebula, an immense cauldron of gas and dust that lies approximately 7500 light-years from Earth. The Carina Nebula contains several ultra-hot stars, including these two star systems and the famous blue star Eta Carinae, which has the highest luminosity yet confirmed. As well as producing incredible amounts of heat, these stars are also very bright, emitting most of their radiation in the ultraviolet and appearing blue in colour. They are so powerful that they burn through their hydrogen fuel source faster than other types of stars, leading to a “live fast, die young” lifestyle. WR 25 is the brightest, situated near the centre of the image. The neighbouring Tr16-244 is the third brightest, just to the upper left of WR 25. The second brightest, to the left of WR 25, is a low mass star located much closer to the Earth than the Carina Nebula. Stars like WR 25 and Tr16-244 are relatively rare compared to other, cooler types. They interest astronomers because they are associated with star-forming nebulae, and influence the structure and evolution of galaxies.

Read more ….