The black hole pulled the outer star away from the tight binary system. The doomed star's momentum was transferred to the stellar twosome, boosting the duo to escape velocity from the galaxy. As the pair rocketed away, they went on with normal stellar evolution. The more massive companion evolved more quickly, puffing up to become a red giant. It enveloped its partner, and the two stars spiraled together, merging into one superstar, the blue straggler that Hubble observed.
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A blue straggler is a relatively young, massive star produced by the merger of two lighter-weight stars. Astronomers used the sharp vision of Hubble's Advanced Camera for Surveys to make two separate observations of the wayward star 3. Team member Jay Anderson of the Space Telescope Science Institute in Baltimore developed a technique to measure the star's position relative to each of 11 distant background galaxies.
These background galaxies form a reference frame in which Anderson compared the star's position in and to calculate how far it had moved. But the quantity of stars in the outer region is much less than in the core, so we have a better chance of finding these unusual objects. Following the extraordinarily successful Servicing Mission 4 SM4 of Hubble Space Telescope HST in May of , the Observatory is now fully equipped with a broad array of powerful science instruments that put it at the pinnacle of its scientific power. Relevant to the subject matter of the Beyond Conference, HST will be well-placed over the next five-plus years to advance our knowledge of the formation of high-redshift galaxies and their growth with cosmic time; the emergence of structure in the early universe via Dark Matter-driven gravitational instability; and the universe's expansion history and any resulting implications for the temporal character of Dark Energy.
These are fitting projects for the iconic facility now celebrating its 20th anniversary in orbit. This mysterious force, discovered in , is pushing our universe apart at ever-increasing speeds. For the first time, astronomers using NASA's Hubble Space Telescope were able to take advantage of a giant magnifying lens in space -- a massive cluster of galaxies -- to narrow in on the nature of dark energy.
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Their calculations, when combined with data from other methods, significantly increase the accuracy of dark energy measurements. This may eventually lead to an explanation of what the elusive phenomenon really is. Scientists aren't clear about what dark energy is, but they do know that it makes up a large chunk of our universe -- about 72 percent. Another chunk, about 24 percent, is thought to be dark matter, also mysterious in nature but easier to study than dark energy because of its gravitational influence on matter that we can see.
The rest of the universe, a mere four percent, is the stuff that makes up people, planets, stars and everything made up of atoms. In their new study, the science team used images from Hubble to examine a massive cluster of galaxies, named Abell , which acts as a magnifying, or gravitational, lens. The gravity of the cluster causes galaxies behind it to be imaged multiple times into distorted shapes, sort of like a fun house mirror reflection that warps your face.
Using these distorted images, the scientists were able to figure out how light from the more distant, background galaxies had been bent by the cluster -- a characteristic that depends on the nature of dark energy. Their method also depends on precise ground-based measurements of the distance and speed at which the background galaxies are traveling away from us. The team used these data to quantify the strength of the dark energy that is causing our universe to accelerate.
They spent the last several years developing specialized mathematical models and precise maps of the matter -- both dark and "normal" -- constituting the Abell cluster. An international team of astronomers using the Hubble Space Telescope reports a significant brightening of the emissions from Supernova A. The results, which appear in this week's Science magazine, are consistent with theoretical predictions about how supernovae interact with their immediate galactic environment.
The team observed the supernova remnant in optical, ultraviolet, and near-infrared light. They studied the interaction between the ejecta from the stellar explosion and a glowing 6-trillion-mile-diameter ring of gas encircling the supernova remnant.
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The gas ring was probably shed some 20, years before the supernova exploded. Shock waves resulting from the impact of the ejecta onto the ring have brightened 30 to 40 pearl-like "hot spots" in the ring. These blobs likely will grow and merge together in the coming years to form a continuous, glowing circle. Source with accompanying image.
One of the biggest, Pluto, is classified as a dwarf planet. The region also supplies us with comets such as famous Comet Halley.
Most TNOs are small and receive little sunlight, making them faint and difficult to spot. Their method promises to turn up hundreds more.
As TNOs slowly orbit the sun, they move against the starry background, appearing as streaks of light in time exposure photographs. The team developed software to analyze hundreds of Hubble images hunting for such streaks. After promising candidates were flagged, the images were visually examined to confirm or refute each discovery. Most TNOs are located near the ecliptic -- a line in the sky marking the plane of the solar system since the solar system formed from a disk of material.
Therefore, the team searched within 5 degrees of the ecliptic to increase their chance of success. They found 14 objects, including one binary two TNOs orbiting each other like a miniature Pluto-Charon system. All were very faint, with most measuring magnitude more than million times fainter than objects visible to the unaided eye.
By measuring their motion across the sky, astronomers calculated an orbit and distance for each object. Combining the distance and brightness plus an assumed albedo or reflectivity , they then estimated the size.
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The newfound TNOs range from 25 to 60 miles km across. Unlike planets, which tend to have very flat orbits known as low inclination , some TNOs have orbits significantly tilted from the ecliptic high inclination.
The team examined the size distribution of TNOs with low- versus high-inclination orbits to gain clues about how the population has evolved over the past 4. Generally, smaller trans-Neptunian objects are the shattered remains of bigger TNOs. Over billions of years, these objects smack together, grinding each other down. The team found that the size distribution of TNOs with low- versus high-inclination orbits is about the same as objects get fainter and smaller.
Therefore, both populations low and high inclination have similar collisional histories. This initial study examined only one-third of a square degree of the sky, meaning that there is much more area to survey. Hundreds of additional TNOs may lurk in the Hubble archives at higher ecliptic latitudes. Fuentes and his colleagues intend to continue their search. This research has been accepted for publication in The Astrophysical Journal and is available online.
Headquartered in Cambridge, Mass. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe. Are they now too cold to do so? Can accreation only occur when the debris is molten? Breaking Waves in the Stellar Lagoon.
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Seen as a massive cloud of glowing dust and gas, bombarded by the energetic radiation of new stars, this placid name hides a dramatic reality. This spectacular object is named after the wide, lagoon-shaped dust lane that crosses the glowing gas of the nebula. This structure is prominent in wide-field images, but cannot be seen in this close-up.
Located four to five thousand light-years away, in the constellation of Sagittarius the Archer , Messier 8 is a huge region of star birth that stretches across one hundred light-years. Clouds of hydrogen gas are slowly collapsing to form new stars, whose bright ultraviolet rays then light up the surrounding gas in a distinctive shade of red. In recent years astronomers probing the secrets of the Lagoon Nebula have found the first unambiguous proof that star formation by accretion of matter from the gas cloud is ongoing in this region.
Young stars that are still surrounded by an accretion disc occasionally shoot out long tendrils of matter from their poles. The Lagoon Nebula is faintly visible to the naked eye on dark nights as a small patch of grey in the heart of the Milky Way.
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