Posted on by Tammy Plotner

Asteroid Lutetia… A Piece Of Earth?

This image of the unusual asteroid Lutetia was taken by ESA’s Rosetta probe during its closest approach in July 2010. Lutetia, which is about 100 kilometres across, seems to be a leftover fragment of the same original material that formed the Earth, Venus and Mercury. It is now part of the main asteroid belt, between the orbits of Mars and Jupiter, but its composition suggests that it was originally much closer to the Sun. Credit: ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

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According to data received from ESA’s Rosetta spacecraft, ESO’s New Technology Telescope, and NASA telescopes, strange asteroid Lutetia could be a real piece of the rock… the original material that formed the Earth, Venus and Mercury! By examining precious meteors which may have formed at the time of the inner Solar System, scientists have found matching properties which indicate a relationship. Independent Lutetia must have just moved its way out to join in the main asteroid belt…

A team of astronomers from French and North American universities have been hard at work studying asteroid Lutetia spectroscopically. Data sets from the OSIRIS camera on ESA’s Rosetta spacecraft, ESO’s New Technology Telescope (NTT) at the La Silla Observatory in Chile, and NASA’s Infrared Telescope Facility in Hawaii and Spitzer Space Telescope have been combined to give us a multi-wavelength look at this very different space rock. What they found was a very specific type of meteorite called an enstatite chondrite displayed similar content which matched Lutetia… and what is theorized as the material which dates back to the early Solar System. Chances are very good that enstatite chondrites are the same “stuff” which formed the rocky planets – Earth, Mars and Venus.

“But how did Lutetia escape from the inner Solar System and reach the main asteroid belt?” asks Pierre Vernazza (ESO), the lead author of the paper.

It’s a very good question considering that an estimated less than 2% of the material which formed in the same region of Earth migrated to the main asteroid belt. Within a few million years of formation, this type of “debris” had either been incorporated into the gelling planets or else larger pieces had escaped to a safer, more distant orbit from the Sun. At about 100 kilometers across, Lutetia may have been gravitationally influenced by a close pass to the rocky planets and then further affected by a young Jupiter.

“We think that such an ejection must have happened to Lutetia. It ended up as an interloper in the main asteroid belt and it has been preserved there for four billion years,” continues Pierre Vernazza.

Asteroid Lutetia is a “real looker” and has long been a source of speculation due to its unusual color and surface properties. Only 1% of the asteroids located in the main belt share its rare characteristics.

“Lutetia seems to be the largest, and one of the very few, remnants of such material in the main asteroid belt. For this reason, asteroids like Lutetia represent ideal targets for future sample return missions. We could then study in detail the origin of the rocky planets, including our Earth,” concludes Pierre Vernazza.

Original Story Source: ESO News Release.

Posted on by Tammy Plotner

Tarantula Nebula Is Growing!

Don’t like spiders? Well, here’s one that will grow on you! Located about 160,000 light years in the web of the Large Magellanic Cloud, star-forming region 30 Doradus is best known as the “Tarantula Nebula”. But don’t let it “bug” you… this space-born arachnid is home to giant stars whose intense radiation causes stellar winds to blast through surrounding gases to give us an incredible view!

When seen through the eyes of the Chandra X-ray Observatory, these huge shockwaves of x-ray energy heat the encompassing gaseous environment up to multi-millions of degrees and show up as blue. The supernovae detonations blast their way outward… gouging out “bubbles” in the cooler gas and dust. They show up hued as orange when observed through infra-red emissions and recorded by the Spitzer Space Telescope.

What’s so special about the Tarantula? Because it is so close, it’s a prime candidate for studying an active HII region. This stellar nursery is the largest in our Local Group and a perfect laboratory for monitoring stellar evolution. Right now astronomers are intensely interested in what causes growth on such a large scale – and their curent findings show it doesn’t have anything to do with pressure and radiation from the massive stars. However, an earlier study had opposing conclusions when it came to 30 Doradus’ central regions. By employing the Chandra Observatory observations, we may just find different opinions!

“Observations show that star formation is an inefficient and slow process. This result can be attributed to the injection of energy and momentum by stars that prevents free-fall collapse of molecular clouds. The mechanism of this stellar feedback is debated theoretically; possible sources of pressure include the classical warm H II gas, the hot gas generated by shock heating from stellar winds and supernovae, direct radiation of stars, and the dust-processed radiation field trapped inside the H II shell.” says Laura Lopez (et al). “By contrast, the dust-processed radiation pressure and hot gas pressure are generally weak and not dynamically important, although the hot gas pressure may have played a more significant role at early times.”

Original Story Source: Chandra News Release. For Further Reading: What Drives the Expansion of Giant H II Regions?: A Study of Stellar Feedback in 30 Doradus.

Posted on by Steve Nerlich

Astronomy Without A Telescope – Orphan Supernovae?

Supernova G292.0+1.8. Like most supernovae it detonated within a host galaxy - in fact ours. Credit: Chandra.

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For some years now astronomers have been scratching their heads over the appearance of supernovae that detonate out in the middle of nowhere – rather than within a host galaxy.

Various hypotheses have been proposed, notably that they might be hypervelocity stars – which are stars flung out of their host galaxy due to an unfortunate coincidence of gravitational interactions. It’s thought that such interactions may accelerate those stars up to a velocity of more than 100 kilometers a second – that is, more than the escape velocity of your average galaxy.

But Zinn et al suggest a more mundane suggestion for their particular orphan supernovae of interest, which is SN 2009z. They propose that it is in a galaxy, it’s just a galaxy that is very difficult to see.

They propose the supernova actually detonated within a low surface brightness galaxy, N271. From the images they have produced, this seems a reasonable claim – it’s just that low surface brightness galaxies (or LSBs) aren’t meant to have supernovae.

Left frame: Sloan Digital Sky Survey image showing the location of the Type IIB supernovae SN 2009z. Right frame: Close-up of the rectangular area taken by the New Technology Telescope (ESO), showing the location of SN 2009z at the cross marks. It seems closely associated with the small galaxy N271, even though such a galaxy is not usually thought capable of supporting massive star formation. Credit: Zinn et al.

Since galaxies can appear as extended objects, rather than as point-like stars, we refer to them as having ‘surface brightness’ – which can vary across the object’s apparent surface. LSB’s are generally isolated field galaxies, rather than being grouped in amongst dense galaxy clusters. They are most often dwarf galaxies as well, but at least one spiral LSB has been identified.

The dimness of LSB galaxies is suggestive of them having almost no active star formation – either being too old, with no free hydrogen remaining for new star formation – or just not dense enough for much star formation to ever have taken off.

But here you have supernova SN 2009z that was most likely was contained within LSB galaxy N271. And SN 2009z was a Type II supernova – a massive and short-lived star that underwent core collapse. Indeed, it was a Type IIb with only a small shell of hydrogen when it detonated. Type IIb supernovae are probably massive stars which lose most, but not all, of their hydrogen shell through having it stripped off by a companion star in a binary system.

This all seems quite unusual behaviour for a galaxy that does not support active star formation. Zinn et al propose that LSB galaxies must go through short bursts of active star formation followed by long quiescent phases of almost no activity. This then suggests that the progenitor star of supernova SN 2009z was formed in the previous starburst period, before N271 quietened down again.

Of course, none of this need suggest that hypervelocity stars don’t exist – indeed several have been discovered since the first confirmed finding in 2005. All those known are associated with the Milky Way, since finding a single isolated hypervelocity star ejected by a distant galaxy is probably beyond the detection of our current technology – unless of course they go supernovae.

But given what we know so far:
• a hypervelocity star arises from a binary system’s unfortunate interaction with a galaxy’s central supermassive black hole;
• one binary member is captured, the other flung violently outwards at escape velocity.
• but, massive stars that go supernovae only have a main sequence life span of the order of millions of years;
• so, even at more than 100 kilometers a second, it’s unlikely that any are going to make it across the many light years distance from the center of a galaxy to its outer boundary before they detonate.

Putting all this together… orphan supernovae? Busted (well, unless we find one anyway).

Further reading: Zinn et al. Supernovae without host galaxies? The low surface brightness host of SN 2009Z.

Posted on by Tammy Plotner

Keck Observatory Locates Two Clouds Of Pristine Gas From The Beginning of Time

Credit: Simulation by Ceverino, Dekel & Primack

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Is there any place in space which hasn’t been affected by time? The answer is yes. Thanks to some very awesome research, the W. M. Keck Observatory and a team of scientists have recently located two clumps of primordial gas which may very well have had its origin within minutes of the Big Bang.

How do we know these gas clouds are so special? In this case, they are simply too disseminated to enable stellar birth and contain no heavy metals which would support it. These diaphanous regions are pure hydrogen and helium… along with a heavier isotope, deuterium. This combination could mean the two billion year old regions are pure – never involved in the star-forming process. An exciting discovery? You bet. The clouds could have possibly survived in an unchanged state – giving us a look at what may have occurred at the dawn of time.

“Despite decades of effort to find anything metal-free in the universe, Nature has previously set a limit to enrichment at no less than one-thousandth that found in the Sun,” said astronomer J. Xavier Prochaska of the University of California Observatories-Lick Observatory, U.C. Santa Cruz. “These clouds are at least 10 times lower than that limit and are the most pristine gas discovered in our universe.”

Prochaska is part of the Keck team and has coauthored a paper reporting on the discovery with Michele Fumagalli of the U.C. Santa Cruz and John O’Meara of Saint Michael’s College in Vermont. “We’ve searched carefully for oxygen, carbon, nitrogen and silicon – the things that are found on Earth and the Sun in abundance,” Fumagalli said. “We don’t find a trace of anything other than hydrogen and deuterium.”

According to the Keck Observatory news release exactly how they can detect dark, cold, diffuse gas about 12 billion light-years away is a story in itself.

“In this case we actually have to do a bit of a trick,” Prochaska explained. “We study the gas in silhouette.” A more distant quasar provides the light for this. The quasar light shines though the gas and the elements in the gas absorb very specific wavelengths of light, which can only be found by splitting the light into very detailed spectra to reveal the dark lines of missing light.

In other words, said Fumagalli, “All of the analysis is on the light we didn’t get.” The clouds absorb only a small fraction of the quasar light that makes it to Earth. “But the signatures of hydrogen absorption are obvious, so there’s no doubt there’s a lot of gas there.”

While some folks might not get excited over the location of immaculate gases, astronomers think differently. This revelation supports their theories of what may have occurred within moments after the Big Bang and what formed at the time of nucleosynthesis. It’s a look back at when hydrogen, helium, lithium and boron originated.

The two pristine gas clouds found by astronomers could sit in one of the filamentary regions visible around galaxies in this image, which are from computer simulations. Credit: Simulation by Ceverino, Dekel & Primack

“That theory has been very well tested at Keck as regards to hydrogen and its isotope deuterium,” said O’Meara. “One of the conundrums of that previous work, however, is that the gas also showed at least trace amounts of oxygen and carbon. The clouds that we have discovered are the first to match the full predictions of BBN.”

What’s more, Keck’s two 10-meter optical/infrared telescopes have shown us what the early universe may have been like. This is the very first time that science has been able to peer into regions where no metals have influenced the environment and no stars have formed.

“What excites me about this discovery is that there is an almost a range of 1,000,000 in the metallicity in gases at that time in the universe,” said Fumagalli. In other words, there were places like our Solar system – where metals are very abundant – and there were also places very unlike today, where metals were still virtually non-existent and the gases were unchanged since almost the beginning of time.”

Original Story Source: Keck Observatory News Release. For Further Reading: Detection of Pristine Gas Two Billion Years After the Big Bang.

Posted on by Jason Rhian

Orion Spacecraft to Launch in 2014

NASA has announced that it will conduct an unmanned test flight called the Exploration Flight Test-1 or EFT-1 in 2014. Image Credit: NASA.gov

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CAPE CANAVERAL, Fla – NASA has announced its intention to launch an unmanned flight of the Orion Spacecraft atop a United Launch Alliance (ULA) Delta IV Heavy launch vehicle – by 2014. This flight test will be added to the contract that the space agency has with aerospace firm Lockheed Martin. The Orion Multi-Purpose Crew Vehicle or Orion MPCV as it is more commonly known – will test out systems that will be employed on the Space Launch System (SLS). If successful, this will allow astronauts to travel beyond low-Earth-orbit (LEO) for the first time in over four decades.

“This flight test will provide invaluable data to support the deep space exploration missions this nation is embarking upon,” said NASA Associate Administrator for Communications David Weaver.

The flight has been dubbed Exploration Flight Test or EFT-1 and will be comprised of two high-apogee orbits that will conclude with a high-energy reentry into the Earth’s atmosphere. Like the Mercury, Gemini and Apollo capsules before it, the Orion MPCV will conduct a water landing.

The test mission will lift off from Cape Canaveral Air Force Station located in Florida. It is designed to provide the space agency with vital flight data regarding how the vehicle handles re-entry and other performance issues.

The test flight will be comprised of two high-apogee orbits followed by a splash down. This flight will provide NASA with crucial information that could potentially lead to changes in the Orion spacecraft's design. Image Credit: NASA

“The entry part of the test will produce data needed to develop a spacecraft capable of surviving speeds greater than 20,000 mph and safely return astronauts from beyond Earth orbit,” said Associate Administrator for Human Exploration and Operations William
Gerstenmaier. “This test is very important to the detailed design process in terms of the data we expect to receive.”

Presumably the use of a Delta IV Heavy would allow NASA to accelerate its human exploration objectives at an accelerated rate. Since the flight will be unmanned, there is no need to man-rate the launch vehicle and given the current economic issues facing the United States, the use of so-called “legacy” hardware could ensure that costs are kept down.

The past year has seen the development of the Orion spacecraft proceed at an accelerated pace. Photo Credit: NASA/Lockheed Martin

NASA has also stated its intention to release competitive solicitations for design proposals for new, advanced liquid or solid boosters to be used on the SLS. Another contract that will be opened for competition will be for payload adaptors for both crewed as well as cargo missions.

The Orion spacecraft was originally part of the Constellation Program. Its design has since been modified – but its mission to one day fly astronauts to the Moon, Mars and beyond – remains. The EFT-1 test flight will allow technicians and NASA officials to better determine what further changes need to be made to best aid the completion of NASA’s exploration goals.

The EFT-1 test flight could pave the way for flights back to the Moon, to the planet Mars and to other destinations throughout the solar system. Image Credit: NASA.gov
Posted on by Nancy Atkinson

Portraits of Our Sun on 11/11/11 at 11:11 UTC

The Sun captured by NASA's Solar Dynamics Observatory Spacecraft.
The Sun captured by NASA's Solar Dynamics Observatory Spacecraft.

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The Solar Dynamics Observatory takes images of the Sun about every 10 seconds, so it easily was able to capture the Sun when the clocks and calendars lined up for a mathematically synchronous readout. Below is another image at the same time in different wavelength.

You can check out what the Sun looks like at anytime of the day or year the the SDO website.

The Sun at 11:11 UTC on 11/11/11 in a different wavelength. Credit: NASA

Posted on by Jason Rhian

ASF 2011 Autograph Show: To Be the Shoulders of Tomorrow’s Titans

KENNEDY SPACE CENTER, Fla – Every year the Astronaut Scholarship Foundation (ASF) hosts its “Astronaut Autograph Show” at Kennedy Space Center in Florida. This year it was held on Nov. 5-6 at the Kennedy Space Center Visitor Complex’s Debus Center. The ASF coordinated with the operators of the Cocoa Beach Air Show to ensure that the show had a very dramatic ending. Continue reading “ASF 2011 Autograph Show: To Be the Shoulders of Tomorrow’s Titans”

Posted on by Nancy Atkinson

Astronomy Cast Ep. 238: Solar Activity

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The Solar Cycle

The Sun looks like a harmless burning ball of fire in the sky: warm, life-giving and forever unchanging. But we know better, don’t we. It’s really a massive ball of churning hydrogen plasma, encased in twisting magnetic field lines, speckled with sunspots, and constantly disgorging vast plumes of radiation and charged particles. The Sun is very active indeed.

Click here to download the episode.

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

“Solar Activity” shownotes on the Astronomy Cast website.

Posted on by Nancy Atkinson

Giant Sunspot Turns to Face the Earth

The full face of the Sun as seen on Nov. 6, 2011, showing AR 1339 and several other sunspots. Credit: Alan Friedman. Click for a stunning larger version.

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What has been billed as the largest sunspot observed in several years has now rotated around to stare straight at Earth. How large is it? Active Region 1339 and the group of sunspots adjacent to it extends more than 100,000 km from end to end and each of the several dark cores is larger than Earth. The now very active Sun has already blasted out several medium- to large-sized solar flares and has the potential to hurl out more.

And the Sun is now dotted with several smaller sunspots as well. Above is an amazing image of all this activity, as captured by astrophotographer Alan Friedman. “This has been a glorious week for solar observers!” Friedman said. “Led by large sunspot region AR1339, the sun’s disk is alive with activity… the most dynamic show in many years.”

Take a look below for an incredible closeup of AR1339 taken by Friedman, as well as a movie from the Solar Dynamics Observatory showing the sunspots rotating into view.

Click on the image for a larger version on Friedman’s website, AvertedImagination.com

From all this activity, there may be a good chance for viewing aurorae. On November 9 at around 1330 UT, a magnetic filament in the vicinity of sunspot complex 1342-1343 erupted, producing a M1-class solar flare and hurling a CME into space, which will probably deliver a glancing blow to Earth’s magnetic field on Nov 11 or 12, according to SpaceWeather.com

A portrait of Active Region 1339 in the wavelength of hydrogen alpha light showing the large sunspot group and the maelstrom of chromosphere that surrounds it. Credit Alan Friedman

And here’s an image from astrophotographer Raymond Gilchrist showing a labeled version of all the current sunspots: 1338, 1339, 1340, 1341, 1342, 1343, 1344.

The 'spotty' Sun on Nov. 10, 2011. Credit: Raymond Gilchrist. Click for version on Flickr.

Raymond used a Baader Solar Continuum Filter and Thousand Oaks Full Solar Filter with a Skywatcher 120mm S/T Refractor,
with a Canon 350D, 1/15th Sec Exp. at ISO400. You can see more of his images at his Flickr page.

Posted on by Nancy Atkinson

Swift Satellite Captures Asteroid 2005 YU55’s Tumbling Flyby

If you want to photograph something in space, what better way than to have a spacecraft take the picture? The Swift Telescope – better known for its study of high-energy outbursts and cosmic explosions – was able to observe the flyby of 2005 YU55, the asteroid that came within 324,600 kilometers (201,700 miles) of Earth this week, and captured its tumbling, rapid motion across the sky.

“Swift’s ultraviolet and X-ray capability gives scientists a unique perspective on comets and asteroids, expanding the spectral window beyond the radio, infrared and optical observations so well handled by big ground-based facilities,” said Sergio Campana, a Swift team member at Brera Observatory in Merate, Italy.” Campana requested that the spacecraft train its telescopes on the asteroid as a target of opportunity.
Continue reading “Swift Satellite Captures Asteroid 2005 YU55’s Tumbling Flyby”