Posted on by Tammy Plotner

Primordial Black Holes, Dark Matter and Stellar Collisions… Oh, My!

Princeton and New York University researchers have simulated the effect of a primordial black hole passing through a star. Primordial black holes are among the objects hypothesized to make up dark matter -- the invisible substance thought to constitute much of the universe -- and astronomers could use the researchers' model to finally observe the elusive black holes. This image illustrates the resulting vibration waves as a primordial black hole (white dots) passes through the center of a star. The different colors correspond to the density of the primordial black hole and strength of the vibration. (Image by Tim Sandstrom)

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Well, we’re off to see the Wizard again, my friends. This time it’s to explore the possibilities of primordial black holes colliding with stars and all the implications therein. If this theory is correct, then we should be able to observe the effects of dark matter first hand – proof that it really does exist – and deeper understand the very core of the Universe.

Are primordial black holes blueprints for dark matter? Postdoctoral researchers Shravan Hanasoge of Princeton’s Department of Geosciences and Michael Kesden of NYU’s Center for Cosmology and Particle Physics have utilized computer modeling to visualize a primordial black hole passing through a star. “Stars are transparent to the passage of primordial black holes (PBHs) and serve as seismic detectors for such objects.” says Kesden. “The gravitational field of a PBH squeezes a star and causes it to ring acoustically.”

If primordial black holes do exist, then chances are great that these type of collisions happen within our own galaxy – and frequently. With ever more telescopes and satellites observing the stellar neighborhoods, it only stands to reason that sooner or later we’re going to catch one of these events. But, the most important thing is simply understanding what we’re looking for. The computer model developed by Hanasoge and Kesden can be used with these current solar-observation techniques to offer a more precise method for detecting primordial black holes than existing tools.

“If astronomers were just looking at the Sun, the chances of observing a primordial black hole are not likely, but people are now looking at thousands of stars,” Hanasoge said.”There’s a larger question of what constitutes dark matter, and if a primordial black hole were found it would fit all the parameters — they have mass and force so they directly influence other objects in the Universe, and they don’t interact with light. Identifying one would have profound implications for our understanding of the early Universe and dark matter.”

Sure. We haven’t seen DM, but what we can see are galaxies that are hypothesized to have extended dark-matter halos and to study the effects the gravity has on their materials – like gaseous regions and stellar members. If these new models are correct, primordial black holes should be heavier than existing dark matter and when they collide with a star, should cause a rippling effect.

“If you imagine poking a water balloon and watching the water ripple inside, that’s similar to how a star’s surface appears,” Kesden said. “By looking at how a star’s surface moves, you can figure out what’s going on inside. If a black hole goes through, you can see the surface vibrate.”

Using the Sun as a model, Kesden and Hanasoge calculated the effects a PBH might have and then gave the data to NASA’s Tim Sandstrom. Using the Pleiades supercomputer at the agency’s Ames Research Center in California, the team was then able to create a video simulation of the collisional effect. Below is the clip which shows the vibrations of the Sun’s surface as a primordial black hole — represented by a white trail — passes through its interior.

“It’s been known that as a primordial black hole went by a star, it would have an effect, but this is the first time we have calculations that are numerically precise,” comments Marc Kamionkowski, a professor of physics and astronomy at Johns Hopkins University. “This is a clever idea that takes advantage of observations and measurements already made by solar physics. It’s like someone calling you to say there might be a million dollars under your front doormat. If it turns out to not be true, it cost you nothing to look. In this case, there might be dark matter in the data sets astronomers already have, so why not look?”

I’ll race you to the door…

Original Story Source: Princeton University News. For Further Reading: Transient Solar Oscillations Driven by Primordial Black Holes.

Posted on by Ray Sanders

How to See the Brightest Supernova in a Generation

Astrophoto: Supernova PTF11kly in M101 by Rick Johnson
Supernova PTF11kly in M101. Credit: Rick Johnson

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Here at Universe Today, we’ve been providing plenty of coverage on the recent supernova in spiral galaxy M101 (AKA Pinwheel Galaxy). Readers have uploaded their images to our Flickr page and have been asking about the event, weeks after it was detected.

While the supernova has been dimming since its peak brightness, most supernova events brighten quickly, but fade slowly. This supernova is by no means visible with the naked eye, but here’s what you need to know to catch a glimpse of the brightest supernova in the past few decades.

First a short primer on M101: Nicknamed the “Pinwheel Galaxy” for its resemblance to the toy, M101’s distinct spiral arms can be imaged with modest amateur astronomy equipment. M101 is about six megaparsecs ( 1 parsec is just over three and one-quarter light years ) away from our solar system, which is over six times more distant than our closest neighbor, the Andromeda Galaxy. M101 is a galaxy that is much larger than our own galaxy – nearly double the size of the Milky Way.

What made M101 newsworthy as of late was the Type Ia supernova discovered inside the galaxy. Discovered nearly a month ago on August 24th, SN 2011fe (initial designation PTF 11kly) started off at around 17th magnitude and recently peaked around magnitude 10 (magnitude 6-7 is limit of “naked-eye” visibility with dark skies).

Scientists and amateur astronomers alike have scrambled to gather data on SN 2011fe. Some observers have even looked through data collected in late August only to see they captured the supernova without knowing it!

Supernova PTF11kly / SN 2011fe in Messier 101. Credit: Joe Brimacombe

By mid-September, though, SN 2011fe has become too faint for casual observers to see, but experienced amateur astronomers can still see it with telescopes. If you don’t have a good-sized “amateur” telescope, you might consider contacting a local astronomy club to see if they are having a “star party” or observing night in your area. To find an astronomy club, check out NASA’s Night Sky Network.

Viewing M101 and SN 2011fe isn’t terribly challenging, so long as you have a decent view to the North. You can find M101 by using the Big Dipper asterism (Ursa Major for the constellation purists). Look for the last two stars of the Big Dipper’s handle (Mizar and Alkaid). Above the midpoint between the two stars is M101. For those with motorized telescopes, start at Mizar, slew a little to the east and up a little. People who are lucky enough to have a computerized, “Go-To” scope can enter the RA and Dec coordinates of 14:03:05.81 , +54:16:25.4.

This week you’ll want to try viewing M101 in late evenings, otherwise you may find it too close to the horizon and washed out by the waning gibbous Moon. To your eyes, M101 will appear as a fuzzy “smudge” in the eyepiece. If you are at a very dark site and use averted (looking slightly to the side of the object) vision you might see some detail with a 12″ or larger telescope. You can certainly view M101 with a telescope as small as 6″, but you really do want to view M101 with as big of a telescope as possible. Don’t use higher power eyepieces to try and make up for a small telescope. Many galaxies, including M101 are best viewed with mid-to-low power eyepieces.

Below is an image generated by Stellarium. In the image are a few constellations and some guide stars you can use to guide your eyes and telescope to M101.

Clear skies and good luck!

Location of M101 at 9 PM ( 33 Degrees N. ) Image generated with Stellarium
Posted on by VirtualAstro

The Mission to Find the Missing Lunar Module

Apollo LM orbiting the sun, Credit: Adrian West http://twitter.com/virtualastro

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Where is the Apollo 10 Lunar lander module? It’s somewhere out there — orbiting the Sun — and there’s a new initiative to try and find it!

The Apollo 10 mission launched on May 18, 1968 and was a manned “dry run” for its successor Apollo 11, testing all of the procedures and components of a Moon landing without actually landing on the Moon itself.

After carrying out a successful lunar orbit and docking procedure, the Lunar Module (called “Snoopy”) was jettisoned and sent into an orbit around the Sun.

After 42 years, it’s believed to still be in a heliocentric orbit and a team of UK and international astronomers working with schools are going to try and find it.

The idea is the brainchild of British amateur astronomer Nick Howes who helped coordinate a very successful asteroid and comet project with schools and Faulkes Telescope during this past summer.

After consulting with people from NASA’s Jet Propulsion Laboratory and other orbital dynamics experts, the Howes has assembled a team of facilities and experts, including the Faulkes Telescope, Space Exploration Engineering Corp, astronomers from the Remanzacco Observatory in Italy and schools across the UK.

They know they have a massive undertaking ahead of them to find Snoopy.

“The key problem which we are taking on is a lack of solid orbital data since 1969,” Howes told Universe Today. “We’ve enlisted the help of the Space Exploration Engineering Corp who have calculated orbits for Apollo 10 and working closely with people who were on the Apollo mission team in the era will help us identify search coordinate regions.”

“We’re expecting a search arc anywhere up to 135 million kilometres in size which is a huge amount of space to look at, ” Howes continued. “We’re aware of the scale and magnitude of this challenge but to have the twin Faulkes scopes assist the hunt, along with schools, plus the fact that we’ll doubtless turn up many new finds such as comets and asteroids makes this a great science project too. We’re also encouraging anyone to have a go as we’ll be posting the coordinates on to the Faulkes Telescope website starting in a few days”

While the challenge ahead of Howes and the team is enormous, and the chances of the team finding Snoopy are very small, the team are enthusing thousands of people with their own “Apollo Mission” – the mission to find the missing Apollo Lunar module.

Credit: Faulkes Telescope
Posted on by Ray Sanders

How Can You See the Sun and the Moon at the Same Time?

A daytime Moon over New Zealand in August 2010. Credit: NASA/Phil Davis

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Did you know that you can see the Moon during the day?

Many people only notice our Moon at night, when there is considerably more contrast between the Moon and the night sky. Being the second brightest object in the sky (after the Sun, of course) and with Venus visible during the day to trained eyes, it’s no real surprise that the Moon is visible during the day.

Why then, do so many people act surprised when they notice the Moon during the day? What makes it possible for the Moon to be visible during the day?

Understanding how and when you can spot the Moon is a matter of knowing the different lunar phases, specifically the relationship between the Sun, Earth and the Moon during each phase. The image below shows the simple geometry responsible for each of the Moon’s distinct phases.

In the diagram it’s pretty easy to see that when Earth is between the Sun and the Moon, we see a full moon. When the Moon is between Earth and the Sun, we see a new Moon. The other phases are simply transitions from new to full and from full back to new.

Schedule of Moon Phases. Times shown indicate when the moon is overhead.
Schedule of Moon Phases. Times shown indicate when the moon is overhead.

Based on the orbital geometry of the Moon, there will certainly be times where the Sun will partially illuminate the Moon, during the day and at night. What makes the lunar cycle even more interesting is that the moon rises about an hour later each day, and yet invariably, a full moon rises near dusk and sets near sunrise. The reverse is true in that a new moon rises near sunrise and sets near dusk.

Looking at the above diagram though, a question comes to mind…
Why don’t we have a lunar eclipse during each full moon, or a solar eclipse each new moon?

I’ll explain the conditions needed for a solar or lunar eclipse in an upcoming article.

In the meantime enjoy the transition from waning gibbous to waning crescent over the next week and get your telescopes out during the weekend of the 25th. The Moon will almost be at its new phase.

If you’d like to learn more about moon phases and when the moon will be visible in your area, the US Naval observatory has a great calculator at: http://aa.usno.navy.mil/data/docs/RS_OneYear.php

Posted on by Tammy Plotner

Stellar Superburst: Neutron Star Blows Away Model

A detailed rendering of the neutron star surface and what the surface might look like during the explosion. Credit: NASA/Dana Berry

[/caption]Imagine an event so catastrophic that it pours more energy out in three hours than the Sun does in a hundred years. Now imagine it a reality. In a study done by Yuri Cavecchi et al. (2011), they’ve witnessed a neutron star outburst which has put all computer modeling for thermodynamic explosions on extreme objects back to square one.

Apparently a strong magnetic field around accreting pulsar IGR J17480-2446 is the culprit for some areas of the star to ignite in the extreme. X-ray binary IGR J17480-2446, as a general rule, should be about one and a half times the mass of the Sun confined in an area of about 25km. This creates a strong gravitational field which extracts gas from its orbiting companion. In turn, this collects on the surface of the primary and kindles a fast, high-energy thermonuclear reaction. In a perfect scenario, this reaction would be spread over the surface evenly, but for some reason in about 10% of case studies some areas burn brighter than others. Just why this happens is a true enigma.

In order to better understand the phenomena, theoretical models were created to test out spin rates. They suggest that rapid rotation stops the burning material from spreading uniformly – much like the Coriolis force develops terrestrial hurricanes. Another hypothesis proposes these conflagrations ride on global-scale waves where one side stays cool and dim as it rises, while the other remains hot and bright. But just which one is viable in the case of this strange pulsar?

“We explore the origin of Type I burst oscillations in IGR J17480–2446 and conclude that they are not caused by global modes in the neutron star ocean. We also show that the Coriolis force is not able to confine an oscillation-producing hot-spot on the stellar surface.” says lead author Yuri Cavecchi (University of Amsterdam, the Netherlands). “The most likely scenario is that the burst oscillations are produced by a hot-spot confined by hydromagnetic stresses.”

What makes the astronomers think this way? One explanation might be the strange properties of J17480 itself. While it obeys the rules when it comes to forming bright patches during thermonuclear events, it break them when it comes to spin rates. Why does this particular star only rotate about 10 times per second when the next slowest does it at 245? This is where the magnetic field theory comes into play. Perhaps when explosions occur, it’s held in place by this invisible, yet powerful, force.

“More theoretical work is needed to confirm this, but in the case of J17480 it is a very plausible explanation for our observations”, says Cavecchi. Co-author Anna Watts further explains their new models – while interesting – might not account for all non-uniform events seen in similar situations. “The new mechanism may only work in stars like this one, with magnetic fields that are strong enough to stop the flame front from spreading. For other stars with this odd burning behavior, the old models might still apply.”

Original Information Source: Netherlands Research School for Astronomy. For Further Reading: Implications of burst oscillations from the slowly rotating accreting pulsar IGR 17480-2446 in the globular cluster Terzan 5.

Posted on by Tammy Plotner

Even Small Galaxies Can Have Big Black Holes

Astronomers detected supermassive black holes in 28 distant, low-mass galaxies, including the four shown in these Hubble Space Telescope images. Image credit: A. Koekemoer, Space Telescope Science Institute.

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The Hubble Space Telescope has done it again. By utilizing a slitless grism, the Wide Field Camera 3 has uncovered evidence that supermassive black holes are right at home in some very small galaxies. Apparently these central black holes began their life when their host galaxies were first forming!

“It’s kind of a chicken or egg problem: Which came first, the supermassive black hole or the massive galaxy? This study shows that even low-mass galaxies have supermassive black holes,” said Jonathan Trump, a postdoctoral researcher at the University of California, Santa Cruz. Trump is first author of the study, which has been accepted for publication in the Astrophysical Journal.

It’s another cosmic conundrum. As we’ve learned, large galaxies are host to central supermassive black holes and many of them are the AGN variety. But the real puzzle is why do some smaller galaxies contain them when most do not? By taking a closer look at dwarf galaxies some 10 billion light-years away, astronomers are reaching back in time to when the Universe was about an estimated quarter of its current age.

“When we look 10 billion years ago, we’re looking at the teenage years of the universe. So these are very small, young galaxies,” Trump said.

If your mind is still wondering what a “slitless grism” is, then wonder no more. It’s part of Hubble’s WFC3 infrared camera that provides spectroscopic information. Thanks to highly detailed information on the different wavelengths of light, the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) team could achieve separate spectra from each sector of the candidate galaxies and identify emissions from black hole sources.

“This is the first study that is capable of probing for the existence of small, low-luminosity black holes back in time,” said coauthor Sandra Faber, University Professor of astronomy and astrophysics at UC Santa Cruz and CANDELS principal investigator. “Up to now, observations of distant galaxies have consistently reinforced the local findings–distant black holes actively accreting in big galaxies only. We now have a big puzzle: What happened to these dwarf galaxies?”

It’s possible they are forerunners of the massive galaxies we see today. “Some may remain small, and some may grow into something like the Milky Way,” Trump said. But this theory is a juxtaposition in itself. According to Faber, “To become big galaxies today, the dwarf galaxies would have to grow at a rate much faster than standard models predict. If they remain small, then nearby dwarf galaxies should also have central black holes. There might be a large population of small black holes in dwarf galaxies that no one has noticed before.”

But these distant little dwarfs aren’t quiet – they are actively forming new stars. According to Trump, “Their star formation rate is about ten times that of the Milky Way. There may be a connection between that and the active galactic nuclei. When gas is available to form new stars, it’s also available to feed the black hole.”

But the Hubble wasn’t the only instrument interested in the 28 small galaxy studies. The team also employed x-ray data acquired by NASA’s Chandra X-ray Observatory. To help refine their information on such small, faint objects, the data was combined to improve the signal-to-noise ratio.

“This is a powerful technique that we can use for similar studies in the future on larger samples of objects,” Trump said. “Together the compactness of the stacked OIII spatial profile and the stacked X-ray data suggest that at least some of these low-mass, low-metallicity galaxies harbor weak active galactic nuclei.”

Original Story Source: University of Santa Cruz News. For Further Reading: A CANDELS WFC3 Grism Study of Emission-Line Galaxies at z~2: A Mix of Nuclear Activity and Low-Metallicity Star Formation.

Posted on by Tammy Plotner

Milky Way Arm Wrestles With Dark Matter

Computer model of the Milky Way and its smaller neighbor, the Sagittarius dwarf galaxy. The flat disk is the Milky Way, and the looping stream of material is made of stars torn from Sagittarius as a result of the strong gravity of our galaxy. The spiral arms began to emerge about two billion years ago, when the Sagittarius galaxy first collided with the Milky Way disk. Image by Tollerud, Purcell and Bullock/UC Irvine

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For a good number of years, astronomers have hypothesized the Sagittarius Dwarf Galaxy has been loaded up with dark matter. As one of our nearest neighboring galaxies and part of our local group, Sag DEG has been hanging around for billions of years and may have orbited us as many as ten times. However, in order to survive the tidal strain of such interaction, this loop-shaped elliptical has got to have some muscle. Now UC Irvine astronomers are speculating on how these close encounters may have shaped the Milky Way’s spiral arms.

In a study released in today’s Nature publication, astronomers are citing telescopic data and computer modeling to show how our local galactic collision has sent streams of stars out in loops in both galaxies. These long streamers continue to collect stellar members and the rotation of the Milky Way forms them into our classic spiral pattern. The news is the presence of dark matter in Sag DEG is responsible for the initial push.

“It’s kind of like putting a fist into a bathtub of water as opposed to your little finger,” said James Bullock, a theoretical cosmologist who studies galaxy formation.

But the little Sagittarius Dwarf, as strong as the dark matter might be, isn’t going to win this cosmic arm wrestling match. Each time we interact, the small galaxy gets further torn apart and about all that’s left is four globular clusters and a smattering of old stars which spans roughly 10,000 light-years in diameter.

“When all that dark matter first smacked into the Milky Way, 80 percent to 90 percent of it was stripped off,” explained lead author Chris Purcell, who did the work with Bullock at UCI and is now at the University of Pittsburgh. “That first impact triggered instabilities that were amplified, and quickly formed spiral arms and associated ring-like structures in the outskirts of our galaxy.”

Will we meet again? Yes. The Sagittarius galaxy is due to strike the southern face of the Milky Way disk fairly soon, Purcell said – in another 10 million years or so.

Original Story Source: University of Irvine News. Further Reading: The Sagittarius impact as an architect of spirality and outer rings in the Milky Way.

Posted on by Ray Sanders

Kepler Mission Discovers “Tatooine-like” Planet

Artist's rendering of Kepler-16b Image Credit: NASA/JPL-Caltech/R. Hurt

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In a news conference today, Kepler mission scientists announced the first confirmed circumbinary planet ( a planet that orbits a binary star system). The planet in question, designated Kepler-16b has been compared to the planet Tatooine from the Star Wars saga.

Would it be possible for someone like Luke Skywalker to stand on the surface of Kepler-16b and see the famous “binary sunset” as depicted in Star Wars?

Despite the initial comparison between Kepler-16b and Tatooine, the planets really only have their orbit around a binary star system in common. Kepler-16b is estimated to weigh about a third the mass of Jupiter, with a radius of around three-quarters that of Jupiter.

Given the mass and radius estimates, this makes Kepler-16b closer to Saturn than the rocky, desert-like world of Tatooine. Kepler-16b’s orbit around its two parent stars takes about 229 days, which is similar to Venus’ 225-day orbit. At a distance of about 65 million miles from its parent stars, which are both cooler than our sun, temperatures on Kepler-16b are estimated in the range of around -100 C.

The team did mention that Kepler-16b is just outside of the habitable zone of the Kepler-16 system. Despite being just outside the habitable zone, the team did mention that it could be possible for Kepler-16b to have a habitable moon, if said moon had a thick, greenhouse gas atmosphere.

Binary Sunset as seen on Tatooine
Tatooine appears to have twin stars like our sun, versus the orange (type K) and red (type M) stars of Kepler-16
During the press conference John Knoll, visual effects supervisor at ILM, mentioned: “When I was a kid, I didn’t think it was going to be possible to make discoveries like this.” Knoll also added, “The science is stranger and cooler than fiction!”

The Kepler mission detects exoplanet candidates by using the transit method which detects the dimming of the light emitted from a star as a planet crosses in front of it. In the case of Kepler-16b, the detection was complicated by the two stars in the system eclipsing each other.

The system’s brightness showed variations even when the stars were not eclipsing each other, which hinted at a third body. What further complicated matters was that the variations in brightness appeared at irregular time intervals. The irregular time intervals hinted that the stars were in different positions in their orbit each time the third body passed. After studying the data, the team came to the conclusion that the third body was orbiting, not just one, but both stars.

“Much of what we know about the sizes of stars comes from such eclipsing binary systems, and most of what we know about the size of planets comes from transits,” added Kepler scientist Laurance Doyle of the SETI Institute. “Kepler-16 combines the best of both worlds, with stellar eclipses and planetary transits in one system.” Doyle’s findings will be published in the Sept. 15th issue of the journal Science.

The Kepler mission is NASA’s first mission capable of finding Earth-size planets in or near the habitable zone – the region around a star where liquid water can exist on the surface of an orbiting planet. A considerable number of planets and planet candidates have been detected by the mission so far. If you’d like to learn more about the Kepler mission, visit: http://kepler.nasa.gov/

You can also read more about the Kepler-16b discovery at: http://kepler.nasa.gov/Mission/discoveries/kepler16b/

Source: NASA news conference / NASA TV

Ray Sanders is a Sci-Fi geek, astronomer and space/science blogger. Visit his website Dear Astronomer and follow on Twitter (@DearAstronomer) or Google+ for more space musings.

Posted on by Jon Voisey

Help! My Stars are Leaking!

A fast-moving star, Alpha Camelopardalis, creates a stunning bow shock in this new image from WISE. Credit: NASA/JPL-Caltech/WISE Team

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Star clusters are wonderful test beds for theories of stellar formation and evolution. One of the key roles they play is to help astronomers understand the distribution of stellar masses as stars form (in other words, how many high mass stars versus intermediate and low mass stars), known as the Initial Mass Function (IMF). One of the problems is that this is constantly evolving away from the initial distribution as stars die or are ejected from the cluster. As such, understanding these mechanisms is essential for astronomers looking to backtrack from the current population to the IMF.

To assist in this goal, astronomers led by Vasilii Gvaramadze at the University of Bonn in Germany are engaged in a study to search young clusters for stars in the process of being ejected.

In the first of two studies released by the team so far, they studied the cluster associated with the famous Eagle Nebula. This nebula is well known due to the famous “Pillars of Creation” image taken by the aging Hubble Space Telescope which shows towers of dense gas currently undergoing star formation.

Two main methods exist for discovering stars on the lam from their birthplace. The first is to examine stars individually and analyze their motion in the plane of the sky (proper motion) along with their motion towards or away from us (radial velocity) to determine if a given star has sufficient velocity to escape the cluster. While this method can be reliable, it suffers because the clusters are so far away, even though the stars could be moving at hundreds of kilometers per second, it takes long periods of time to detect it.

Instead, the astronomers in these studies search for runaway stars by the effects they have on the local environment. Since young clusters contain large amounts of gas and dust, stars plowing through it will create bow shocks, similar to those a boat makes in the ocean. Taking advantage of this, the team searched the Eagle Nebula cluster for signs of bow shocks from these stars. Searching images from several studies, the team found three such bow shocks. The same method was used in a second study, this time analyzing a lesser known cluster and nebula in Scorpius, NGC 6357. This survey turned up seven bow shocks of stars escaping the region.

In both studies, the team analyzed the spectral types of the stars which would indicate their mass. Simulations of nebulae suggested that the majority of ejected stars are given their initial kick as they have a close pass to the center of a cluster where the density is the highest. Studies of clusters have shown that their centers are often dominated by massive O and B spectral type stars which would mean that such stars would be preferentially ejected. These two studies have helped to confirm that prediction as all of the stars discovered to have bow shocks were massive stars in this range.

While this method is able to find runaway stars, the authors note that it is an incomplete survey. Some stars may have sufficient velocity to escape, but still fall under the local sound speed in the nebula which would prevent them from creating a bow shock. As such, calculations have predicted that roughly 20% of escaping stars should create detectable bow shocks.

Understanding this mechanism is important because it is expected to play the dominant role in the evolution of the mass distribution of clusters early in their life. An alternative method of ejection involves stars in a binary orbit. If one star becomes a supernova, the sudden mass loss suddenly decreases the gravitational force holding the second star in orbit, allowing it to fly away. However, this method requires that a cluster at least be old enough for stars to have evolved to the point they explode as supernova, delaying this mechanism’s importance until at least that point and allowing the gravitational sling-shot effects to dominate early on.

Posted on by Jason Major

Senate Saves the James Webb Space Telescope!

JWST's mirror segments are prepped for testing at NASA's Marshall Space Flight Center. NASA/Chris Gunn.

The 2012 fiscal year appropriation bill, marked up today by the Senate, allows for continued funding of the James Webb Space Telescope and support up to a launch in 2018! Yes, it looks like this bird is going to fly.

JWST's mirror segments are prepped for testing at NASA's Marshall Space Flight Center. NASA/Chris Gunn.

The James Webb Space Telescope will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System. JWST will be a large infrared telescope with a 6.5-meter primary mirror.

Thanks to everyone who contacted their representatives and expressed their support of the JWST, to all the websites out there that made it particularly simple to do so, and of course to all the state representatives who stood behind the program and didn’t allow it to get mothballed. The space science community thanks you and the current and future generations of astronomers, physicists, cosmologists and explorers thank you.

“In a spending bill that has less to spend, we naturally focus on the cuts and the things we can’t do. But I’d like to focus on what we can do. The bill invests more than $12 billion in scientific research and high impact research and technology development, to create new products and new jobs for the future.”

– CJS Subcommittee Chairwoman Barbara Mikulski

In addition to continued funding for the telescope the 2012 bill also allots the National Aeronautics and Space Administration $17.9 billion (a reduction of $509 million or 2.8 percent from the 2011 enacted level) and preserves NASA’s portfolio balanced among science, aeronautics, technology and human space flight investments, including the Orion Multipurpose Crew Vehicle, the heavy lift Space Launch System, and commercial crew development.

In this tighter economy, all of the agencies funded under the bill are also called on to be better stewards of taxpayers’ dollars, and waste and overspending will be much more closely monitored.

Read the bill summary here.

Go JWST!

NOTE: While the JWST program has been specifically included in today’s markup, the bill itself still needs to be approved by the full appropriations committee and then go to the Senate floor for a vote. It then must be reconciled with the House version before receiving final appropriation. Still, this is definitely one step closer to getting the JWST off the ground! Read more on ScienceInsider here.

You can show your continued support for the JWST by liking the Save the James Webb Space Telescope Facebook page and – even more importantly – by contacting your congressperson and letting them know you care!