Astronomers were surprised when they spotted these stars because physical models show that only an unusual type of old star can be as hot and as bright in ultraviolet light.

While Hubble has spied these ultra-blue stars before in Andromeda, the new observation covers a much broader area, revealing that these stellar misfits are scattered throughout the galaxy's bustling center.

Astronomers used Hubble's Wide Field Camera 3 to find roughly 8,000 of the ultra-blue stars in a stellar census made in ultraviolet light, which traces the glow of the hottest stars. The study is part of the multi-year Panchromatic Hubble Andromeda Treasury survey to map stellar populations across the galaxy.

"We were not looking for these stars. They stood out because they were bright in ultraviolet light and very different from the stars we expected to see," said Julianne Dalcanton of the University of Washington in Seattle, leader of the Hubble survey.

The team's results are being presented at the American Astronomical Society meeting in Austin, Texas. A paper describing the finding will be published in The Astrophysical Journal.

The telescope spied the stars within 2,600 light-years of the core. After analyzing the stars for nearly a year, Dalcanton's team determined that they were well past their prime. "The stars are dimmer and have a range of surface temperatures different from the extremely bright stars we see in the star-forming regions of Andromeda," said Phil Rosenfield of the University of Washington, the paper's lead author.

As these stars evolved, puffing up to become red giants, they ejected most of their outer layers to expose their blue-hot cores. When normal sun-like stars swell up to become red giants, they lose much less material and therefore never look as bright in the ultraviolet.

"We caught these stars when they're the brightest, just before they become white dwarfs," said team member Leo Girardi of the National Institute for Astrophysics's Astronomical Observatory of Padua. "It is likely that there are many other similarly hot stars in this central part of Andromeda at earlier stages of their lives. But such stars are too dim for Hubble to see because they're mixed in with a crowd of normal stars."

The astronomers have proposed two possible scenarios to explain why these blue stars evolve differently. According to Rosenfield, the most likely scenario is that the stars are rich in chemical elements other than hydrogen and helium. Observations with ground-based telescopes have shown the stars in the galaxy's hub have an abundant supply of "heavy elements," which makes it easier for stars to eject lots of material into space late in life.

In this scenario radiation from the star is more efficient at pushing on gas laced with heavy elements, which drives away the material, like wind moving a thick sail. Although all the stars in the core are enriched in heavy elements, the bright blue stars may contain especially high amounts, which help trigger the mass loss.

The study also shows that the number of blue stars decreases with distance from the core, tracing the drop in the amount of heavy elements.

Another possible explanation is that the blue stars are in close binary systems and have lost mass to their partners. This mass loss would expose the stars' hot cores. The astronomers were surprised to find that the ultra-blue stars are distributed in the galaxy in the same way as a population of binary stars with similar masses that were found in X-ray observations by NASA's Chandra X-ray Observatory.

The astronomers' next step is to create simulations of these stars to try to determine which scenario is the one that leads them on a different evolutionary path.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

]]> Fri, 03 FEB 2012 13:11:18 AEST Onsala, Sweden (SPX) Oct 06, 2011 - The discovery proves what astronomers have long believed: that the galaxies which are the universe's most efficient star-factories are also supernova factories. The astronomers used a worldwide network of radio telescopes in five countries, including Sweden, to be able to create extremely sharp images of the galaxy Arp 220.

The scientists observed around 40 radio sources in the center of the galaxy Arp 220. These radio sources are hidden behind thick layers of dust and gas and invisible in ordinary telescopes. To discover the nature of these radio sources, they made measurements at different radio wavelengths and watched how they changed over several years.

"With all the data in place, we can now be certain that all seven of these sources are supernovae: stars that exploded in the last 60 years," says Fabien Batejat, main author of the article about the discovery.

So many supernovae have never before been detected in the same galaxy. The number is nevertheless consistent with how fast stars are forming in Arp 220.

"In Arp 220, we see far more supernovae than in our galaxy. We estimate that a star explodes in Arp 220 once every quarter. In the Milky Way, there is only one supernova per century," says Rodrigo Parra, astronomer at the European Southern Observatory in Chile and member of the team.

John Conway is professor of observational radio astronomy at Chalmers and deputy director of Onsala Space Observatory.

"Arp 220 is well-known as a place where star formation is very efficient. Now we have been able to show that star factories like this are also supernova factories," he says.

The radio measurements have also given researchers insight into how radio waves are generated in supernovae and their remnants.

"Our measurements show that a supernova's own magnetic field is what gives rise to its radio emission, not the magnetic fields in the galaxy around it," says Fabien Batejat.

]]> Fri, 03 FEB 2012 13:11:18 AEST Washington DC (SPX) Oct 04, 2011 - The detailed views of star-formation in the Antennae Galaxies are the first astronomical test images released to the public from the growing Atacama Large Millimeter/submillimeter Array (ALMA) and confirm that this new telescope has surpassed all others of its kind.

In celebration of the start of the Atacama Large Millimeter/submillimeter Array's (ALMA) Early Science observations, the National Radio Astronomy Observatory (NRAO) has released an image of a merging pair of galaxies as seen by the growing ALMA telescope. The detailed views of star-formation in the Antennae Galaxies confirm that this new telescope, while far from completed, and with only a fraction of its ultimate imaging capability, will surpass all others of its kind.

The image gives but a hint of ALMA's promise to make unprecedented contributions to understanding the once-hidden activities of the early Universe.

The Observations
"We chose the impressive interacting system called the Antennae galaxies as a test subject," said Dr. Alison Peck, an astronomer from the NRAO who is serving in Chile as ALMA Deputy Project Scientist during its years of careful construction and rigorous testing, "because it is in the process of undergoing the type of spectacular, violent merger that many galaxies may have undergone since their formation, but that we can rarely catch in action."

This image is a composite of views of the Antennae taken with several different types of telescopes, including test data from ALMA (orange and yellow, and shown alone in the inset). Like the view from an ultrasound of an expectant mother's womb, ALMA reveals hidden starbirth nestled inside otherwise obscuring dust clouds.

"ALMA's test views of the Antennae show us star-forming regions on a level of detail that no other telescope on Earth or in space has attained. This capability can only get much better as ALMA nears completion," said Dr. Mark McKinnon, North American ALMA Project Manager from the NRAO in Charlottesville, Virginia.

The inset boxes show regions imaged in additional, higher detail. With this weekend's start of ALMA's first official cycle of observing, called Early Science, a team of North American astronomers is poised to make even more detailed observations of the Antennae.

"The collision of these two galaxies has turned them into an impressive star-making factory. With Hubble, we've seen the formation of thousands of massive super star clusters, each with thousands or even millions of young stars in them," said team leader, Dr. Brad Whitmore of the Space Telescope Science Institute.

"With ALMA, we will focus on the heart of the collision, the interaction region where the two galaxies are crashing together. We can then study the formation of the Antennae's most impressive fireworks and look into the cores of the giant molecular clouds where the star clusters are born."

By 2013, ALMA will have more than tripled its current number of telescopes to 66. With the telescopes combined into a single system by one of the world's fastest, special-purpose supercomputers, and aimed at many more objects all across the sky, ALMA will reveal a Universe never before seen.

The Antennae Galaxies
About six hundred million years ago, this peculiar object was two separate, beautiful spiral galaxies passing by each other for the first time. Now, it captivates astronomers as the youngest and nearest colliding galaxy pair ever found.

Spiral galaxies are a spectacular example of gravity's beautiful geometries, stunning structures created when swirling gas and dust are drawn together. In a spiral galaxy's center, a central massive black hole hoards a giant glowing bulge of gas and stars for itself, while out in the spinning disk, rippling compression waves trigger stars to form along its dusty, gas-rich arms. In isolation, a spiral galaxy would make stars like this until its gas was too thinly spread to fuel any new ones.

In contrast, colliding galaxies like the Antennae are an equally spectacular example of gravity's jumbled catastrophes. If two spirals form too near each other, their centers will slowly tug each other closer, and the gas and stars from their outer disks will lag behind, eventually trailing off into tails. As the central denser parts of the galaxies slowly collide over millions of years, their gas and dust clouds often compress together, eventually producing clumps of new stars.

For guided video tours of ALMA, please enjoy our ALMA Explorer.

]]> Fri, 03 FEB 2012 13:11:18 AEST Boston MA (SPX) Oct 05, 2011 - High-mass stars are important because they are responsible for much of the energy pumped into our galaxy over its lifetime.

Unfortunately, these stars are poorly understood because they are often found relatively far away and can be obscured by gas and dust. The star cluster NGC 281 is an exception to this rule.

It is located about 9,200 light years from Earth and, remarkably, almost 1,000 light years above the plane of the Galaxy, giving astronomers a nearly unfettered view of the star formation within it.

NGC 281 is known informally as the "Pacman Nebula" because of its appearance in optical images. In optical images the "mouth" of the Pacman character appears dark because of obscuration by dust and gas, but in the infrared Spitzer image the dust in this region glows brightly.

]]> Fri, 03 FEB 2012 13:11:18 AEST Geauga County OH (SPX) Aug 31, 2011 - An overcast sky in Geauga County, Ohio, did not dampen the enthusiasm of the 1,500 people attending Observatory Park's dedication on 20 August, when it announced its full status as an International Dark Sky Park (IDSPark). The new park is the latest member of the growing IDSPlaces program, the flagship of the International Dark-Sky Association's ongoing efforts to promote stewardship of the night sky.

The idea for Observatory Park began with the donation of a 25-inch telescope and a small parcel of land. Several years later, the park acquired nationally recognized Nassau Observatory and the land adjacent to it. Ironically, Nassau Observatory was moved from Cleveland to Geauga County in 1957 due to increasing light pollution, but has not been used since the early 1990s.

The finished park, with an observatory, two telescopes, and permanent astronomy-themed exhibits on a 1,034-acre preserve in Monteville Township, provides an exciting link to the history of astronomy in Ohio while creating resources for the future. Refurbishment of Nassau is anticipated.

In 2008, the park earned provisional dark sky status during construction for its ambitious plans for lighting, education, and conservation. Observatory Park is the first park of the Geauga Park District to apply for full International Dark Sky Park status and the first park ever to receive provisional status. It is the eighth International Dark Sky Park in the world, and one of just over a dozen to earn the prestigious IDSPlace distinction.

GPD has a mission of protecting wildlife habitat, including unspoiled forests and wetlands. The IDA commends park officials for recognizing that preservation of the nighttime environment is an essential ingredient for the protection of natural spaces.

Science professionals from numerous universities, the Great Lakes Science Center, and the Cleveland Museum of Natural History collaborated with local astronomy organizations and school districts for Observatory Park's programs and design. Astronomy-inspired interactive sculptures adorn the site. A seismograph and weather station displays live feeds of local atmospheric conditions, and five telescope pads with electrical outlets invite stargazing.

The telescope in the central plaza will be open for public events including star parties, celestial occurrences, and collaborations with local groups and non-profit organizations.

All park lighting is fully shielded and task specific. Terry McGowan, lighting designer and member of the IDA Board of Directors, adds "The lighting was not only designed to be dark sky friendly and efficient; it was designed to be a prototype of what outdoor lighting can now do to reduce existing sky glow without compromising safety and function."

LED fixtures in the public event center and parking lot have source controls to adjust automatically, dimming during a full Moon. More than two-dozen pine trees border the parking lot to shield stargazers from incoming headlights. Facilities also utilize living roofs, solar panels, and waterless sanitation.

The entire park is funded by philanthropic dollars. Observatory Park admirably leveraged their provisional status to garner publicity, funding, and programming. An innovative "lighting naming right" was presented to donors to fund the desired fixtures.

Park promoters lead the community in dark sky preservation efforts. During construction, exhibits throughout northeast Ohio in 2009 reached an estimated combined audience of 22,000. Geauga Park District management is attempting to retrofit all of the lights in its many parks to conform to IDSPark guidelines and GPD staffers are working with Monteville Township to encourage passage of a lighting ordinance. GPD Executive Director Tom Curtin proposed the idea of a county-wide Dark Sky Reserve to county commissioners in December 2008.

Observatory Park is also a host site of one of the first IDA Night Sky Brightness Monitors. These Internet linked, solar-powered devices were developed to collect data on sky quality at astronomical sites.

The monitor, developed in part by the International Dark-Sky Association through a grant from the National Science Foundation, provides unprecedented educational opportunities, many administered locally by Observatory Park. Data from the SkyMonitor will allow park managers to make long-term measurements of the brightness of the sky over the park to ensure its continued protection.

As a host to a SkyMonitor, two telescopes, and numerous interpretative displays, Observatory Park provides rare educational opportunities that will change the outlook of night sky conservation in the region.

IDA executive director Bob Parks remarks, "The park's exceptional lighting plan represents the pinnacle of thoughtful design and embodies the ideals of conservation that are apparent throughout the park's facilities. IDA wholeheartedly commends the visionaries behind Observatory Park for their superb execution of a cutting-edge lighting design and persistent public outreach."

]]> Fri, 03 FEB 2012 13:11:18 AEST Munich, Germany (SPX) Aug 11, 2011 - The most distinctive features of the bright galaxy NGC 3521 are its long spiral arms that are dotted with star-forming regions and interspersed with veins of dust. The arms are rather irregular and patchy, making NGC 3521 a typical example of a flocculent spiral galaxy. These galaxies have "fluffy" spiral arms that contrast with the sweeping arms of grand-design spirals such as the famous Whirlpool galaxy or M 51, discovered by Charles Messier.

NGC 3521 is bright and relatively close-by, and can easily be seen with a small telescope such as the one used by Messier to catalogue a series of hazy and comet-like objects in the 1700s. Strangely, the French astronomer seems to have missed this flocculent spiral even though he identified several other galaxies of similar brightness in the constellation of Leo.

It was only in the year that Messier published the final version of his catalogue, 1784, that another famous astronomer, William Herschel, discovered NGC 3521 early on in his more detailed surveys of the northern skies.

Through his larger, 47-cm aperture, telescope, Herschel saw a "bright center surrounded by nebulosity," according to his observation notes.

In this new VLT picture, colourful, yet ill defined, spiral arms replace Herschel's "nebulosity". Older stars dominate the reddish area in the centre while young, hot blue stars permeate the arms further away from the core.

Oleg Maliy, who participated ESO's Hidden Treasures 2010 competition [1], selected the data from the FORS1 instrument on ESO's VLT at the Paranal Observatory in Chile that were used to create this dramatic image.

Exposures taken through three different filters that passed blue light (coloured blue), yellow/green light (coloured green), and near-infrared light (coloured red) have been combined to make this picture.

The total exposure times were 300 seconds per filter. Oleg's image of NGC 3521 was a highly ranked entry in the competition, which attracted almost 100 entries.

VISTA works in the infrared and is the world's largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

[1] ESO's Hidden Treasures 2010 competition gave amateur astronomers the opportunity to search through ESO's vast archives of astronomical data, hoping to find a well-hidden gem that needed polishing by the entrants. To find out more about Hidden Treasures, visit

]]> Fri, 03 FEB 2012 13:11:18 AEST Beijing (XNA) Aug 09, 2011 - About 3,000 astronomers will get together in Beijing in August 2012 to attend the 28th congress of the International Astronomical Union (IAU).

The Chinese Academy of Sciences (CAS) and the China Association for Science and Technology said the 28th congress will be held from August 20 to 31.

The China Astronomical Society representing China won the bid to host the congress for the first time at the 26th congress in Prague four years ago.

The 12-day Beijing congress will include eight large academic seminars, 25 small-scale symposiums, four lectures, as well as elections for the new IAU leadership.

Astronomical studies worldwide are booming, and major scientific issues, such as "dark matter" and "dark energy," possibly will fundamentally transform people's knowledge of the universe, said CAS Vice President Zhan Wenlong.

China's astronomical research has made "historical progress" in terms of observational studies, equipment and technological development, Zhan said.

Founded in 1919, the IAU promotes and safeguards astronomy through international cooperation. It has 10,077 individual members in 90 countries worldwide, 70 of which are national members.

]]> Fri, 03 FEB 2012 13:11:18 AEST Arlington VA (SPX) Jul 12, 2011 - With the deadline of the fundraising campaign approaching, the Friends of Arlington's David M. Brown Planetarium have been making an all out, last ditch effort to hit the goal set in April 2010 by Dr. Patrick Murphy, Superintendent of Arlington Public Schools (APS).

An online 10-day challenge to raise $25,000 was met with enthusiastic response - with over 200 people contributing $25,167.

In addition, a donor in Northern Virginia, who has chosen to remain anonymous, brought the campaign to a dramatic and successful conclusion with a grant of $50,000, deposited directly to the Friends bank account.

In the most recent count, over 3,500 individuals, businesses, and foundations have contributed over $435,000, far surpassing the goal of $402,800, and meeting the deadline for saving Arlington's planetarium.

The additional funds will go to excellent use, now that the survival of the planetarium is assured. The amount required by Dr. Murphy, $402,800, was the estimated cost of replacing the star projector with a state-of-the-art digital planetarium projector, replacing the seats, updating the lighting system, and repairing the interior of the dome.

The estimate was based on a 2009 study led by George Mason University professor, Dr. Harold Geller. It is entirely possible that the costs of these items will have changed in the two years since the study was completed.

The Friends of Arlington's Planetarium will continue to provide support, advocacy, and advice to APS in the future, to make sure the planetarium remains up-to-date, available to the community and schools alike, and fully integrated into the APS science, technology, engineering, and mathematics (STEM) curriculum.

]]> Fri, 03 FEB 2012 13:11:18 AEST Orlando FL (SPX) Jun 29, 2011 - Calling all amateur star gazers: Scientists need your help. A team from Southern Illinois University in Edwardsville has developed the website IceHunters, which challenges the public to discover potential destinations for a NASA mission at the very edge of the solar system set to happen around 2015.

"I think it's a great idea," said Yanga Fernandez, a University of Central Florida physics assistant professor and comet expert. "Actually that's kind of how I started. When I was 10, I used to search the sky for interesting objects with my dad. And in high school I worked hard to find Halley's Comet, which wasn't easy in suburban Florida. I learned a lot of astronomy along the way."

Today Fernandez holds a Ph.D. degree in astronomy and is among the world's experts on comets. He is part of an international team that recently published two articles about comets visited by spacecraft.

The articles appear in recent issues of Icarus and The Astrophysical Journal. Fernandez, who grew up in Washington and Florida, also is working with another international team to take a unique survey of about 100 comets using the Spitzer Space Telescope and Earth-bound telescopes to determine some of the properties of typical, run-of-the-mill comets.

Fernandez said the IceHunters challenge will not only excite people about space exploration, but it also gives scientists potentially hundreds of extra eyes.

"Up to now, what we know about comets is based on comets of opportunity," Fernandez said. "There are several comets like Halley that people can probably name. We know quite a bit about them because they have come close enough to earth or are bright enough for us to take a pretty good look. But we don't know much about the vast majority of comets out there because they are so far away."

For the contest, dozens of images from the Kuiper Belt - an area beyond Neptune at the outer edges of the solar system - have been taken by powerful telescopes and posted on the website. Participants are invited to view the images and mark potential targets of interest. Guidelines and a brief tutorial will help volunteers interpret what to look for in the images. The site is called IceHunters because objects far from the sun should be cold and icy.

But this isn't simply an academic exercise. The New Horizons mission that launched from the Kennedy Space Center in 2006 is on its way to the outer solar system. The spacecraft flew past Jupiter in 2007 giving scientists a wealth of new data. It is scheduled to rendezvous with Pluto in 2015.

If the right object or objects can be found - anything from comets to asteroids to other unknowns - the spacecraft will take images and other measurements and beam them back to Earth for study. After the rendezvous, scientists believe the spacecraft will have just enough fuel to head deeper into the Kuiper Belt.

"This type of amateur-professional approach benefits all of us," said Humberto Campins, an international expert on asteroids and colleague of Fernandez at UCF. "If this collaboration does identify an object accessible to a rendezvous with NASA's New Horizons spacecraft, the contributions to this mission and to our understanding of the outer Solar System will be significant."

For Fernandez, the challenge recalls that spark in his childhood that led to a lifelong career.

"Most of us start out as amateur astronomers whether it's in our backyards with a pair of binoculars or on a balcony with a low-powered telescope," he said.

"This is just a way to take advantage of all the passion and interest and, hopefully, inspire the next generation of space explorers."

]]> Fri, 03 FEB 2012 13:11:18 AEST Washington DC (SPX) Jun 24, 2011 - One of the most complicated and dramatic collisions between galaxy clusters ever seen is captured in this new composite image. This collision site, known officially as Abell 2744, has been dubbed "Pandora's Cluster" because of the wide variety of different structures seen. Data from NASA's Chandra X-ray Observatory are colored red, showing gas with temperatures of millions of degrees.

In blue is a map showing the total mass concentration (mostly dark matter) based on data from the Hubble Space Telescope (HST), the European Southern Observatory's Very Large Telescope (VLT), and the Japanese Subaru telescope. Optical data from HST and VLT also show the constituent galaxies of the clusters.

The "core" region shows a bullet-shaped structure in the X-ray emitting hot gas and a separation between the hot gas and the dark matter. (As a guide, local peaks in the distribution of hot gas and overall matter in the different regions are shown with red and blue circles respectively).

This separation occurs because electric forces between colliding particles in the clouds of hot gas create a friction that slows them down, while dark matter is unaffected by such forces.

In the Northwest ("NW") region, a much larger separation is seen between the hot gas and the dark matter. Surprisingly, the hot gas leads the "dark" clump (mostly dark matter) by about 500,000 light years.

This unusual configuration may require a slingshot scenario, as suggested previously by scientists, to fling the hot gas ahead of the dark matter during an earlier interaction. In the North ("N") and the West ("W") two additional examples of hot gas separated from dark matter may be visible. The latter appears to exhibit the largest separation seen to date between hot gas and dark matter.

The authors of this study retraced the details of the collision, and deduce that at least four different galaxy clusters coming from a variety of directions were involved. To understand this history, it was crucial to map the positions of all three types of matter in Abell 2744. Although the galaxies are bright, they make up less than 5% of the mass in Abell 2744. The rest is hot gas (around 20%) visible only in X-rays, and dark matter (around 75%), which is completely invisible.

Dark matter is particularly elusive as it does not emit, absorb or reflect light, but only makes itself apparent through its gravitational attraction. To pinpoint the location of this mysterious substance the team used a phenomenon known as gravitational lensing. This is the bending of light rays from distant galaxies as they pass through the gravitational field present in the cluster.

The result is a series of telltale distortions in the images of galaxies in the background of optical observations. By carefully plotting the way that these images are distorted, a map is constructed of where the mass - and hence the dark matter - actually lies (shown in blue).

Galaxy clusters are the largest gravitationally bound objects in the Universe and have become powerful tools in cosmology studies. Further studies of Abell 2744 may provide a deeper understanding of the way that these important objects grow and provide new insight into the properties of dark matter.

]]> Fri, 03 FEB 2012 13:11:18 AEST Subscribe to our daily selection of space, military, environment and energy newsletters responseText http://visitor.constantcontact.com/manage/optin/ea?v=0016gbbKsaiGSpQFojVO8ZoHw%3D%3D