Archive
Shedding Light On The Power Of M 82′s Superwinds
An international team of astronomers, led by Dr. Kazuya Matsubayshi (Kyoto University), has discovered that outflows of gas from starburst galaxy M 82 collide with a “cap” of gas clouds 40,000 light years away from the galactic disk. Shockwaves from M 82′s central starburst region are the most likely source of the bright clouds within the cap. The large light-gathering power of Subaru Telescope’s 8.2-m mirror and its ability to produce highly detailed images enabled the researchers to make these findings, which provide important clues about the wind’s power.
The central regions of starburst galaxies are sites of immense star formation. They give birth to thousands of massive stars, which are dozens of times heavier than the Sun and then explode as supernovae when they die. Many supernovae explosions heat the gas around them to temperatures of more than a million degrees, and this hot gas flows out from the galaxy as galactic wind. These winds are so powerful that they may play an important role in the evolution of galaxies and the inter-galactic medium.
Full Story: http://www.naoj.org/Pressrelease/2012/12/26/index.html
A Hidden Treasure In The Large Magellanic Cloud
Credit: NASA, ESA. Acknowledgement: Josh Lake
The Large Magellanic Cloud (LMC) is ablaze with star-forming regions. From the Tarantula Nebula, the brightest stellar nursery in our cosmic neighbourhood, to LHA 120-N 11, part of which is featured in this Hubble image, the small and irregular galaxy is scattered with glowing nebulae, the most noticeable sign that new stars are being born.
The LMC is in an ideal position for astronomers to study the phenomena surrounding star formation. It lies in a fortuitous location in the sky, far enough from the plane of the Milky Way that it is neither outshone by too many nearby stars, nor obscured by the dust in the Milky Way’s centre. It is also close enough to study in detail (less than a tenth of the distance of the Andromeda Galaxy, the closest spiral galaxy), and lies almost face-on to us, giving us a bird’s eye view.
LHA 120-N 11 (known as N11 for short) is a particularly bright region of the LMC, consisting of several adjacent pockets of gas and star formation. NGC 1769 (in the centre of this image) and NGC 1763 (to the right) are among the brightest parts.
Full Story and Photos: http://www.spacetelescope.org/news/heic1301/
Light From The Darkness
Credit: ESO/F. Comeron
An evocative new image from ESO shows a dark cloud where new stars are forming, along with a cluster of brilliant stars that have already emerged from their dusty stellar nursery. The new picture was taken with the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile and is the best image ever taken in visible light of this little-known object.
On the left of this new image there is a dark column resembling a cloud of smoke. To the right shines a small group of brilliant stars. At first glance these two features could not be more different, but they are in fact closely linked. The cloud contains huge amounts of cool cosmic dust and is a nursery where new stars are being born. It is likely that the Sun formed in a similar star formation region more than four billion years ago.
This cloud is known as Lupus 3 and it lies about 600 light-years from Earth in the constellation of Scorpius (The Scorpion). The section shown here is about five light-years across.
Full Story, Photo & Links: http://www.eso.org/public/news/eso1303/
A Cloudy Mystery
Mysterious galactic cloud is the black object on the left. Galactic center is the bright spot on the right. Credit: NASA/Spitzer/Benjamin et al., Churchwell et al.
It’s the mystery of the curiously dense cloud. And astronomers at the California Institute of Technology (Caltech) are on the case.
Near the crowded galactic center, where billowing clouds of gas and dust cloak a supermassive black hole three million times as massive as the sun—a black hole whose gravity is strong enough to grip stars that are whipping around it at thousands of kilometers per second—one particular cloud has baffled astronomers. Indeed, the cloud, dubbed G0.253+0.016, defies the rules of star formation.
According to conventional wisdom, clouds of gas that are this dense should clump up to create pockets of even denser material that collapse due to their own gravity and eventually form stars. One such gaseous region famed for its prodigious star formation is the Orion Nebula. And yet, although the galactic-center cloud is 25 times denser than Orion, only a few stars are being born there—and even then, they are small. In fact, the Caltech astronomers say, its star-formation rate is 45 times lower than what astronomers might expect from such a dense cloud.
“It’s a very dense cloud and it doesn’t form any massive stars—which is very weird,” says Jens Kauffmann, a senior postdoctoral scholar at Caltech.
Full Story: http://www.caltech.edu/content/cloudy-mystery
NASA’s Hubble Reveals Rogue Planetary Orbit For Fomalhaut B
Newly released NASA Hubble Space Telescope images of a vast debris disk encircling the nearby star Fomalhaut and a mysterious planet circling it may provide forensic evidence of a titanic planetary disruption in the system.
Astronomers are surprised to find the debris belt is wider than previously known, spanning a section of space from 14 to nearly 20 billion miles from the star. Even more surprisingly, the latest Hubble images have allowed a team of astronomers to calculate the planet follows an unusual elliptical orbit that carries it on a potentially destructive path through the vast dust ring.
The planet, called Fomalhaut b, swings as close to its star as 4.6 billion miles, and the outermost point of its orbit is 27 billion miles away from the star. The orbit was recalculated from the newest Hubble observation made last year.
“We are shocked. This is not what we expected,” said Paul Kalas of the University of California at Berkeley and the SETI Institute in Mountain View, Calif.
Full Story: http://www.nasa.gov/mission_pages/hubble/science/rogue-fomalhaut.html
Also: http://hubblesite.org/newscenter/archive/releases/2013/01
Wide Binary Stars Can Wreak Havoc In Planetary Systems
An international team of astrophysicists has shown that planetary systems with very distant binary stars are particularly susceptible to violent disruptions, more so than if the systems had two stellar companions with tighter orbits around each other.
The team, led by Northwestern University’s Nathan Kaib, conducted 3,000 computer simulations to study the effects of binary stellar companions (some with tight orbits around each other and others with wide or distant orbits) on the formation and evolution of planetary systems.
The researchers found that wide binary stars in planetary systems can lead to dramatic events over time. In one hypothetical system, the researchers added a wide binary companion to the Earth’s solar system. This triggered at least one of four giant planets (Jupiter, Saturn, Uranus and Neptune) to be ejected in almost half of the simulations.
ALMA Shows How Young Star And Planets Grow Simultaneously
Astronomers have used the ALMA telescope to get their first glimpse of a fascinating stage of star formation in which planets forming around a young star are helping the star itself continue to grow, resolving a longstanding mystery. The young system, about 450 light-years from Earth, is revealing its complex gravitational dance to the ever-sharpening vision of the Atacama Large Millimeter/submillimeter Array (ALMA), scheduled for completion this year.
As the planets pull in more material, they also leave a wake in their trail that clears out a gap in the disk. Such gaps have been observed in the dust disks surrounding a number of still-forming solar systems. During this process, the star also continues to grow more massive, leading to the question of how material can get through the gap cleared by the protoplanets and onto the star.
“This has been a bit of a mystery, but now we have found a process that allows the star to continue to grow despite the gap,” said Simon Casassus, of the University of Chile and the Millennium Nucleus for Protoplanetary Disks, who led an international research team.
Full Story: http://www.nrao.edu/pr/2013/protogap/
Also: http://www.eso.org/public/news/eso1301/
Exploding Star Missing From Formation Of Solar System
A new study published by University of Chicago researchers challenges the notion that the force of an exploding star prompted the formation of the solar system.
In this study, published online last month in Earth and Planetary Science Letters, authors Haolan Tang and Nicolas Dauphas found the radioactive isotope iron 60 — the telltale sign of an exploding star—low in abundance and well mixed in solar system material. As cosmochemists, they look for remnants of stellar explosions in meteorites to help determine the conditions under which the solar system formed.
They discovered that levels of iron 60 were uniform and low in early solar system material. They arrived at these conclusions by testing meteorite samples.
Full Story: http://news.uchicago.edu/article/2012/12/14/exploding-star-missing-formation-solar-system
Astronomers Go Infrared To Map Brightest Galaxies In Universe
A group of astronomers from the University of Hawaii at Manoa, the U.S. Mainland, Canada, and Europe recently used the twin telescopes of the W. M. Keck Observatory on Mauna Kea, Hawaii, to conduct a census of the brightest, but until now unseen, galaxies in the distant Universe, bringing astronomers one step closer to understanding how galaxies form and evolve.
These galaxies glow so brightly at infrared wavelengths that they would outshine our own Milky Way by hundreds, maybe thousands, of times. They are forming stars so quickly that between 100 and 500 new stars are born in each galaxy every year, and have been coined “starbursts” by astronomers.
While it’s not clear what gives these galaxies their intense luminosity, it could be the result of a collision between two spiral-type galaxies, similar to the Milky Way and Andromeda Galaxies. Or they could be in a particularly gas-rich region of space, where galaxies form stars quickly due to constant bombardment from gas and dust.
Despite their brightness, these galaxies are nearly invisible at the wavelengths our eyes and most telescopes on Earth can see because they contain huge amounts of dust, which absorbs visible starlight. But they were detectable directly in the infrared from observations at the Herschel Space Observatory, said Dr. Caitlin Casey, a Hubble fellow at the UH Manoa Institute for Astronomy and the lead scientist behind the new results. “Herschel is an infrared space telescope sensitive to wavelengths not observable from within Earth’s atmosphere,” she said.
Full Story: http://keckobservatory.org/news/astronomers_go_infrared_to_map_brightest_galaxies_in_universe
Also: http://www.esa.int/esaSC/SEMXN4F16AH_index_0.html
Also: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=51199
Astronomers Discover And “Weigh” Infant Solar System
Astronomers have found the youngest still-forming solar system yet seen, an infant star surrounded by a swirling disk of dust and gas more than 450 light-years from Earth in the constellation Taurus.
The star currently has about one-fifth the mass of the Sun, but, the scientists say, will likely pull in material from its surroundings to eventually match the Sun’s mass. The disk surrounding the young star contains at least enough mass to make seven Jupiters, the largest planet in our Solar System.
“This very young object has all the elements of a solar system in the making,” said John Tobin, of the National Radio Astronomy Observatory. Tobin and his colleagues used the Submillimeter Array and the Combined Array for Millimeter-wave Astronomy to study the object, called L1527 IRS, residing in a stellar nursery called the Taurus Cloud.
Full Story: http://www.nrao.edu/pr/2012/youngsystem/
