Space

Astronomers have spied a faraway star system that is so unusual, it was one of a kind - and then its discovery helped them pinpoint a second one much closer to home.

They discovered the first star system 13 million light years away, tucked inside Holmberg IX, a small galaxy that is orbiting the larger galaxy M81. They studied it between January and October 2007 with the Large Binocular Telescope (LBT) on Mt. Graham in Arizona.

The star system is unusual, because it’s what the astronomers have called a “yellow supergiant eclipsing binary” -- it contains two very bright, massive yellow stars that are very closely orbiting each other. In fact, the stars are so close together that a large amount of stellar material is shared between them, so that the shape of the system resembles a peanut.


UC Irvine scientists have discovered a cluster of galaxies in a very early stage of formation that is 11.4 billion light years from Earth – the farthest of its kind ever to be detected. These galaxies are so distant that the universe was in its infancy when their light was emitted.

The galaxy proto-cluster, named LBG-2377, is giving scientists an unprecedented look at galaxy formation and how the universe has evolved. Before this discovery, the farthest known event like this was approximately 9 billion light years away.

“When you observe objects this far away, you are actually seeing the universe as it was a very long time ago,” said Jeff Cooke, a McCue Postdoctoral Fellow in physics and astronomy at UCI and lead author of this study. “It is as if a timeline is just sitting out there in front of you. These galaxies represent what the universe looked like well before the Earth existed.”

NGC 2397, pictured in this image from Hubble, is a classic spiral galaxy with long prominent dust lanes along the edges of its arms, seen as dark patches and streaks silhouetted against the starlight. Hubble’s exquisite resolution allows the study of individual stars in nearby galaxies.

Located nearly 60 million light-years away from Earth, the galaxy NGC 2397 is typical of most spirals, with mostly older, yellow and red stars in its central portion, while star formation continues in the outer, bluer spiral arms. The brightest of these young, blue stars can be seen individually in this high resolution view from the Hubble’s Advanced Camera for Surveys (ACS).


Astrophysicists say may be one step closer to understanding how new planets form. A circumstellar disk with telltale signs of planet formation around the star AB Aurigae could be a new planet in the works.

Ben R. Oppenheimer, assistant curator in the American Museum of Natural History's Department of Astrophysics, and colleagues have used the Lyot Project coronograph attached to a U.S. Air Force telescope on Maui, Hawaii, to construct an image of material that seems to be coalescing into a body from the gas and dust cloud surrounding AB Aurigae, a well-studied star.

The body is either a planet or a brown dwarf - something with mass between a star or a planet. Brown dwarfs have been found orbiting stars since a team that included Oppenheimer first discovered one in 1995.


March 19,2008 marked the brightest ever cosmic explosion observed from Earth ( see Georg von Hippel's article here and the news article here). The outburst denoted as GRB 080319B was probably the death of a massive star leading to the creation of a black hole.

For the first time the birth of a black hole has been filmed. Cameras of the "Pi of the Sky" project recorded this remarkable event with a 4 minutes sequence of 10-second images. In under 20 seconds the object became so bright that it was visible with the naked eye. Then it began fading and in 4 minutes was 100 times fainter. At that time the observation was taken over by larger telescopes.

GRB 080319B brightnes measured by "Pi of the Sky" collaboration


White dwarfs are good timekeepers, and as such, hold clues about the age of the cosmos.

“Once a white dwarf forms, all it does is sit and cool, so we can measure the temperature of a white dwarf, and, using some theoretical understandings, figure out how long it took the star to cool to that temperature, and hence determine how old it is,” says Judi Provencal, assistant professor of physics and astronomy at the University of Delaware, director of the Delaware Asteroseismic Research Center (DARC), and resident astronomer at Mt. Cuba Astronomical Observatory in Greenville, Del.. “The coolest white dwarf we know of is about 2,500 degrees,” she notes. “This corresponds to an age for the galaxy of about 10 billion years.”


NASA's Cassini spacecraft tasted and sampled a surprising organic brew erupting in geyser-like fashion from Saturn's moon Enceladus during a close flyby on March 12. Scientists are amazed that this tiny moon is so active, "hot" and brimming with water vapor and organic chemicals.

New heat maps of the surface show higher temperatures than previously known in the south polar region, with hot tracks running the length of giant fissures. Additionally, scientists say the organics "taste and smell" like some of those found in a comet. The jets themselves harmlessly peppered Cassini, exerting measurable torque on the spacecraft, and providing an indirect measure of the plume density.


Astronomers using data from NASA’s Chandra X-ray Observatory, the Gemini Observatory and ESA’s XMM-Newton Observatory have made the best determination of the power of a supernova explosion long after it was visible from Earth.

By observing the remnant of a supernova that occurred about 400 years ago and a light echo from the initial explosion, the teams have established the validity of a new method for studying a type of supernova that produces most of the iron in the universe. The researchers studied the supernova remnant and the supernova light echo that are located in the Large Magellanic Cloud (LMC), a small galaxy about 160,000 light years from Earth

This combination of X-ray and optical images shows the aftermath of a powerful supernova explosion in the Large Magellanic Cloud (LMC), a small galaxy about 160,000 light years from Earth. The debris from this explosion (upper inset) shows the lowest energy X-rays are shown in red, the intermediate energies are green and the highest energies are blue. The light echo image (lower inset) shows light from the original supernova explosion that has bounced off dust clouds in the neighboring regions of the LMC (the light echoes are shown in blue and stars in orange). The large optical image shows emission lines of hydrogen (H-alpha) in red, singly-ionized sulfur in green and doubly-ionized oxygen in blue. The image highlights regions of star formation in the LMC, including supernova remnants and giant structures carved out by multiple supernovas. Credits:Chandra: NASA/CXC/Princeton/C.Badenes et al. MCELS: NOAO/AURA/NSF/S.Points, C.Smith & MCELS team. Light echo: NOAO/CTIO/Harvard/A.Rest et al.


As Georg von Hippel wrote about here, a powerful stellar explosion detected March 19 by NASA's Swift satellite has shattered the record for the most distant object that could be seen with the naked eye.

The explosion was a gamma ray burst. The Very Large Telescope in Chile and the Hobby-Eberly Telescope in Texas measured the burst's redshift at 0.94. A redshift is a measure of the distance to an object. A redshift of 0.94 translates into a distance of 7.5 billion light years, meaning the explosion took place 7.5 billion years ago, a time when the universe was less than half its current age and Earth had yet to form. This is more than halfway across the visible universe.

CLICK ABOVE FOR LARGER IMAGE. The extremely luminous afterglow of GRB 080319B was imaged by Swift's X-ray Telescope (left) and Optical/Ultraviolet Telescope (right). This was by far the brightest gamma-ray burst afterglow ever seen - and from 7.5 billion light years away. Credit: NASA/Swift/Stefan Immler, et al.


Located at the University of Utah, the High Resolution Fly's Eye (HiRes) is an experiment to study the highest energy cosmic rays to determine the energy, direction, and chemical composition of the incident particle.

Final results show that the most energetic particles in the universe rarely reach Earth at full strength because they come from great distances, so most of them collide with radiation left over from the birth of the universe.

The findings are based on nine years of observations at the now-shuttered observatory on the U.S. Army’s Dugway Proving Ground. They confirm a 42-year-old prediction – known as the Greisen-Zatsepin-Kuzmin (GZK) “cutoff,” “limit” or “suppression” – about the behavior of ultrahigh-energy cosmic rays, which carry more energy than any other known particle.