This solar eclipse happens only once every 27 years, and John Monnier was there to see it.
Epsilon Aurigae is a star system about 2,000 light years from Earth. Astronomers have been able to see it for nearly two centuries, and noticed that it dims every 27 years or so. It made sense to assume that they were dealing with a binary star system, with a larger primary star and a smaller secondary star circling around the first. But that didn’t answer all their questions. Why, for instance, did the primary star normally appear dimmer than it should? And if there is a smaller star orbiting the main star, why can’t we see it? To explain that, astronomers developed the unlikely theory that a thick disk of dust was orbiting the smaller star in the same plane as the smaller star’s orbit of the larger star [UPI].
Stardust just can’t seem to stay out of the news. NASA’s comet chaser, named Stardust, returned a sample of celestial material to Earth in 2006 that has produced numerous fascinating findings. Those include the study we covered last week, in which scientists showed that materials that formed near our sun made it out to the far reaches of the solar system to collect on comets. This week, it’s not NASA astronomers making the headlines, but rather citizen scientists who appear to have found the first evidence of interstellar dust in the Stardust samples.
Stardust’s main mission was to gather material from the comet called Wild 2. But on the way, the team deployed a secondary panel of aerogel to try to catch interstellar dust. The researchers hoped to catch 100 or so interstellar grains from the weak but continuous flux in open space. The elements in these grains were forged in stars, but coalesced into grains in the empty space between stars [Nature News]. However, there’s much less dust in interstellar space than there is in a comet tail, and it moves faster, making it harder to catch. When scientists started looking at the sample dropped down to the Utah desert in 2006, it wasn’t clear if Stardust had nabbed any interstellar dust at all.
Waltzing black holes, star-destroying black holes; it’s a black hole bonanza as the American Astronomical Society meets this week in Washington DC.
First, the orbiting pairs: Just about every galaxy has a supermassive black hole at its heart that is millions if not billions the size of our sun. Logic would suggest that when two galaxies merge, astronomers would see the two great black holes orbiting each other, but so far they’ve had tough luck, astronomer Julie Comerford says. “We expect the universe to be littered with these waltzing black holes,” Comerford said. “But until recently, only a few had ever been found.” Those missing black hole pairs posed problems for theories of how galaxies merge and grow [Wired.com].
And the exoplanet count marches on. A few days ago astronomers announced they had found a handful of new planets around sun-like stars, some only 29 light years away. Now, in a study published today in Nature, a team led by David Charbonneau unveils a new super-Earth that’s hot, watery, and only 2.68 times the size of our own world.
The planet currently bares the name GJ 1214b, and while Charbonneau says it’s probably not habitable (because of the 400-degree Fahrenheit surface temperature), it’s not too far off the mark. Geoffrey W. Marcy, a planet hunter from the University of California, Berkeley, wrote in an accompanying article in Nature that the new work provided “the most watertight evidence so far for a planet that is something like our own Earth, outside our solar system” [The New York Times].
As the tally of known planets beyond our solar system continues to grow, so does the number of them that look familiar—planets close to Earth’s size around stars that resemble our sun. Today astronomers announced that they’ve found a new batch of planets that not only fit that description but also reside in our cosmic neighborhood.
Three planets with masses ranging from 5.3 to 24.9 Earth masses were found orbiting the star 61 Virginis, which is 28 light years from Earth in the constellation of Virgo [Herald Sun]. That star can be seen with the naked eye under dark skies, and team member Chris Tinney says the system is strikingly like our own, noting that Neptune is only 17 Earth masses. In addition, NASA’s Spitzer Space Telescope recently found a ring of dust around 61 Virginis that’s about twice the distance from that star as Pluto is from our sun. The region between the newly discovered planets and that disk remains unexplored, the astronomers say, and could be the home of even more planets.
Astronomers want you… to help them match pictures of cosmic collisions, which are known as “galactic mergers.” Studying these mergers could explain why the universe has the mix of galaxy types – from those with wound-up spiral arms to compact balls of stars – that it does. And it turns out that the human eye is much better than a computer at matching up images of real mergers with randomly-selected images of simulated mergers [SPACE.com]. So naturally, astronomers want to enlist the eyes of Internet users to help them.
The website, Galaxy Zoo Mergers, features a new game that bears (it must be said) only a mild resemblance a Vegas slot machine, with a real galactic merger image in the middle and eight randomly selected images of simulated mergers in the slots around it. Players pick out the best matches and can even manipulate the number of stars they see or an image’s orientation to make a better match. Says researcher Chris Lintott: “By randomly cycling through the millions of simulated possibilities and selecting only the very best matches, they are helping to build up a profile of what kinds of factors are necessary to create the galaxies we see in the universe around us – and, hopefully, having fun, too” [SPACE.com].
This is the latest project from Galaxy Zoo to rely on crowdsourcing. Over the past two years, Galaxy Zoo has enlisted 250,000 Internet users to classify hundreds of thousands of galaxies from the Sloan Digital Sky Survey – an effort that so far has resulted in 15 scientific papers, either submitted or published [MSNBC]. This new project will focus on 3,000 merger images, including some new ones taken by the Hubble Space Telescope. The researchers say their attempts to understand the dynamics of a galactic merger is like trying to understand a car crash– they hope to find out what caused it, and what the final outcome will be for the galaxies involved.
A supernova that was observed in 1680 by Britain’s first Astronomer Royal, John Flamsteed, has been revealed to have produced a strange little neutron star that will give astronomers insight into how such stars are born and mature. The remains of the supernova, known as Cassiopeia A, have been something of a mystery to astronomers. Supernovae usually leave behind an extremely dense object such as a black hole or neutron star. But for decades no such object was seen at the centre of Cassiopeia A [Nature News]. Now new observations suggest that the 330-year-old neutron star escaped detection because of its odd atmosphere.
Instead of resembling more mature neutron stars, which are surrounded by hydrogen, this baby star is blanketed in carbon gas – a discovery that could provide important new insights into the evolution of neutron stars [Physics World]. The new study, published in Nature, suggests that the star is still extremely hot in the aftermath of the supernova–about 2 billion degrees Fahrenheit. This overheated condition caused a nuclear fusion reaction on the star’s surface that converts all the hydrogen and helium into carbon gas, researchers say. As time goes on, and as the star cools, the researchers think the surface fusion reaction will stop and the star will develop a more traditional hydrogen atmosphere.
The quest to find a second Earth–a potentially habitable planet that’s about the size of our home, but that lies in a distant solar system–has hit a snag. The Kepler space telescope was expected to be well on its way to detecting Earth-sized exoplanets by now, but an electronic glitch is slowing it down. The delays are caused by noisy amplifiers in the telescope’s electronics. The team is racing to fix the issue by changing the way data from the telescope is processed, but the delay could mean that ground-based observers now have the upper hand in the race to be the first to spot an Earth twin [Nature News].
Kepler, which was launched in March, uses the transit method to detect exoplanets; it’s watching a patch of 100,000 stars in hopes of detecting the brief dimming of a star’s light, which indicates that a planet has passed in front of the star. Kepler focuses light onto 42 light-detecting chips, called CCDs, each of which monitors stars in a different part of the telescope’s field of view. Each CCD is split into two for the purposes of sending data back to Earth, for a total of 84 data channels. Three of these channels are plagued by electronic noise that makes stars in their field of view appear to flicker – “like it’s changing its brightness at a rapid rate”, says Kepler chief scientist William Borucki [New Scientist]. That’s awkward, since the artificial flickers could obscure the real dimming that occurs during a planet’s transit.
Talk about a long trip. An exploding star‘s burst of light traveled 13 billion years, from the early days of the universe to the present day, before being detected by astronomers here on Earth. Researchers say this exploding star is the most distant blast ever seen.
The light from the distant explosion, called a gamma-ray burst, first reached Earth on April 23 and was detected by NASA’s Swift satellite. Gamma-ray bursts are thought to be associated with the formation of star-sized black holes as massive stars collapse. Within hours, telescopes around the world were turned on the burst — the most violent explosions in the universe — observing its fading afterglow to glean clues about its source and location [SPACE.com].
Planets, planets, everywhere! Astronomers have announced the discovery of 32 new planets orbiting distant stars, bringing the list of known exoplanets up to more than 400. The batch of freshly discovered worlds include four that are only five or six times the mass of Earth, an encouraging sign in the quest for a truly Earth-like world that could support life. Researcher Stephane Udry says the discovery is exciting because it suggests that low-mass planets could be numerous in our galaxy. “From [our] results, we know now that at least 40% of solar-type stars have low-mass planets. This is really important because it means that low-mass planets are everywhere, basically” [BBC News].
The discovery was made with the HARPS telescope at the European Southern Observatory‘s facility in Chile. HARPS uses the so-called wobble method to detect planets, in which researchers look for the slight quiver in a star’s regular movements that indicates the gravitational tug of an orbiting planet.
Planets were found around a surprising variety of star types. Gas giant planets were found orbiting “metal-poor” stars — those lacking in elements other than hydrogen and helium — which until now had been considered unlikely places for planets to form [Washington Post]. Researchers also located four exoplanets around relatively cool, small stars known as M-class red dwarfs, and will continue to examine such stars for signs of Earth-like planets. The team expects to keep spotting planets by the dozen, says Udry: “Nature doesn’t like a vacuum so if there is space to put a planet it will put a planet there” [Reuters].
Image: European Southern Observatory. Artist’s impression of a newly discovered planet orbiting the star Gliese 667 C, which is part of a triple star system.
It was a tough repair job that one astronaut called brain surgery in space, but it sure was worth it. NASA has just released the first images taken by the refurbished Hubble Space Telescope following the five-day servicing mission carried out by the crew of the space shuttle Atlantis in May, and it's clear that the mission went off without a hitch. Both the two new cameras and the repaired equipment are producing stunningly clear pictures of galaxies, nebulas, and stars. The breathtaking images that follow will both delight the public and allow astronomers to probe the universe's deepest mysteries.
This celestial "butterfly" is actually the pattern made by a dying star, which ejected vast clouds of gas that were then set glowing by ultraviolet radiation. The two "wings" of the nebula stretch across two light-years of space.
The Mount Wilson Observatory has allowed astronomers to gaze at the heavens for more than a century from a peak in the San Gabriel Mountains, just northeast of Los Angeles, but the devastating conflagration known as the Station Fire that ripped through the Angeles National Forest over the past week had stargazers wondering if the historic facility was about to go up in smoke. The flames got so close at one point that firefighters abandoned the facility, but now L.A. County Deputy Fire Chief Jim Powers has assured astronomers that he foresees “another hundred years for Mount Wilson Observatory.” This is the story of how firefighters saved the birthplace of modern astronomy as well as a virtual forest of communication towers that serve the region [AP].
On Monday night, the scene was grim. The observatory had been hastily evacuated that day, and only two-dozen firefighters stood overnight sentry, positioned along the gloomy perimeters of the observatory and towers. A greater number might have been deployed, but there were more pressing priorities in the urban elevations — the protection of hillside homes [Los Angeles Times]. By daybreak, fire chiefs made the call to retreat from the mountaintop, where firefighters could easily be trapped by the oncoming flames. “It’s not worth dying for,” said Los Angeles County Fire Department Battalion Chief Steve Martin [Los Angeles Times].
It’s a galaxy-eat-galaxy world out there. A new study of the Andromeda galaxy, the closest neighbor to our own Milky Way at 2.5 million light years away, has mapped Andromeda in unprecedented detail and found evidence that it grew through devouring smaller galaxies. Stars and dwarf galaxies that got too close to Andromeda were ripped from their usual surroundings. “What we’re seeing right now are the signs of cannibalism,” said study lead author Alan McConnachie…. “We’re finding things that have been destroyed … partly digested remains” [AP].
Astronomers had already posited the “hierarchical model” in which small galaxies combine to form large ones, but the new study shows the model in action. The map shows stars in bright streams and clumps that were also likely ripped from dwarf galaxies that once orbited Andromeda [New Scientist]. Researchers say the clumps of stars around the edge of Andromeda couldn’t have formed there, because there wouldn’t have been enough gas to give birth to them.
Looking for the best place on Earth to gaze at the stars? Scientists have identified the exact spot on the planet that provides the greatest view of the heavens. The location, called Ridge A, is deep in the Antarctic interior, according to a study published in the Publications of the Astronomical Society.
You’ll want to bundle up, though, because the 13,297-foot-high location has an average winter temperature of about -94 degrees Fahrenheit. It’s so inhospitable that researchers say that no human has ever set foot on Ridge A.
To search for the perfect site to take pictures of the heavens, a U.S.-Australian research team combined data from satellites, ground stations and climate models in a study to assess the many factors that affect astronomy — cloud cover, temperature, sky-brightness, water vapor, wind speeds and atmospheric turbulence [LiveScience]. Scientists believe that a telescope set in place on Ridge A could take pictures as well as the Hubble Space Telescope, which is orbiting the Earth, thanks to the area’s lack of wind and weather.
In a star system 330 light years away from Earth, astronomers have spotted a giant planet that booms around its parent star in tight, fast circles, completing an orbit (the planet’s “year”) in less than one Earth day. The exoplanet, known as Wasp-18b, is so close to its star that researchers say it appears to be spiraling inwards to its fiery doom. But the odds of seeing a planet in its death throes are so low that researchers are searching for alternate explanations, and say the planet could force scientists to rethink established ideas about planetary forces known as tidal interactions [National Geographic News].
The planet is known as a “hot Jupiter,” meaning that it’s a massive gas giant like our own solar system’s Jupiter, but it orbits in close proximity to its star. Current theories say that such a massive planet so close to its star should be pulling on the host star, creating a tidal effect similar to the moon’s pull on Earth. At that range the planet’s pull would be so strong that it would drain energy from its orbit, causing the planet to rapidly fall into the star [National Geographic News]. But if that’s the case, the planet would meet its death in less than a million years. Since the star system is thought to be about 1 billion years old, the odds of catching the planet in its last stages are one in a thousand.
80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles on the day's most compelling topics.
80beats is written by Veronique Greenwood and Valerie Ross. This team darts through each day's science news faster than the ruby-throated hummingbird that beats its wings 80 times per second. Send ideas, tips, suggestions, and complaints to [azeeberg at discovermagazine dot com].
Stardust just can’t seem to stay out of the news. NASA’s comet chaser, named Stardust, returned a sample of celestial material to Earth in 2006 that has produced numerous fascinating findings. Those include the study 
Waltzing black holes, star-destroying black holes; it’s a black hole bonanza as the American Astronomical Society 
And the 
As the tally of known planets beyond our solar system continues to grow, so does the number of them that look familiar—planets close to Earth’s size around stars that resemble our sun. Today 
Astronomers want you… to help them match pictures of cosmic collisions, which are known as “galactic mergers.”
A supernova that was observed in 1680 by Britain’s first Astronomer Royal, John Flamsteed, has been revealed to have produced a strange little neutron star that will give astronomers insight into how such stars are born and mature. 
The quest to find a second Earth–a potentially habitable planet that’s about the size of our home, but that lies in a distant solar system–has hit a snag. The 
Talk about a long trip. An exploding 
Planets, planets, everywhere! Astronomers have announced the discovery of 32 new planets orbiting distant stars, bringing the list of known 
The Mount Wilson Observatory has allowed astronomers to gaze at the heavens for more than a century from a peak in the San Gabriel Mountains, just northeast of Los Angeles, but the devastating conflagration known as the Station Fire that ripped through the Angeles National Forest over the past week had stargazers wondering if the historic facility was about to go up in smoke. The flames got so close at one point that firefighters abandoned the facility, but now L.A. County Deputy Fire Chief Jim Powers has 
It’s a galaxy-eat-galaxy world out there. A new study of the Andromeda galaxy, the closest neighbor to our own Milky Way at 2.5 million light years away, has mapped Andromeda in unprecedented detail and found evidence that it grew through devouring smaller galaxies. Stars and dwarf galaxies that got too close to Andromeda were ripped from their usual surroundings. “What we’re seeing right now are the signs of cannibalism,” said study lead author Alan McConnachie…. “We’re finding things that have been destroyed … partly digested remains” [
Looking for the best place on Earth to gaze at the 
In a star system 330 light years away from Earth, astronomers have spotted a giant planet that booms around its parent 
