Universe Today

May 5, 2013December 23, 2015 by Elizabeth Howell

Star’s Dying Gasp May Signal Black Hole’s Birth

Where is the Nearest Black Hole — Artist concept of matter swirling around a black hole. (NASA/Dana Berry/SkyWorks Digital)

A distinctive flash of light emanating from a dying star may make it possible for astronomers to watch a black hole being born, according to new research.

This burst of light, which might last three to 10 days, could be visible in optical light and also in infrared, which shows the heat signature of cosmic objects. While not as bright as a supernova — an exploding star — this signal could occur somewhere in the sky as often as once a year, according to simulations performed at the California Institute of Technology.

“That flash is going to be very bright, and it gives us the best chance for actually observing that this event occurred,” stated Caltech postdoctoral scholar Tony Piro, who led the research that is published in Astrophysical Journal Letters. “This is what you really want to look for.”

A big star essentially turns into a black hole when it falls into itself due to its large mass. The collapse shoots out protons and electrons from the core, creating neutrons and temporarily turning the core into a neutron star (a really, really dense object). This process also makes up neutrinos, which are infinitesimal but also extremely fast, moving nearly as fast as light does and bleeding the star of energy.

Combining observations done with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. The black hole blows a huge bubble of hot gas, 1,000 light-years across or twice as large and tens of times more powerful than the other such microquasars. The stellar black hole belongs to a binary system as pictured in this artist's impression. Credit: ESO/L. Calçada — Combining observations done with ESO’s Very Large Telescope and NASA’s Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. The black hole blows a huge bubble of hot gas, 1,000 light-years across or twice as large and tens of times more powerful than the other such microquasars. The stellar black hole belongs to a binary system as pictured in this artist’s impression. Credit: ESO/L. Calçada

A 1980 paper, CalTech stated, showed that “this rapid loss of mass means that the gravitational strength of the dying star’s core would abruptly drop.” Hydrogen-filled layers at the top of the star would then fall outward and create a shock wave moving at more than two million miles an hour.

More recently, astronomers at the University of California, Santa Cruz discovered that the shock wave’s friction against the gas would heat up the plasma and make it glow, potentially for as long as a year. But that would be very faint from Earth-borne telescopes.

This is where the new CalTech research comes in. The university is already involved in black hole research, including the Nuclear Spectroscopic Telescope Array (NuSTAR). You can check out a video about NuSTAR below.

Piro’s simulations focus on when shock waves hit the surface of the star. It’s this process that would produce a burst of light, perhaps 10 to 100 times brighter than the other glow that astronomers foresaw.

The next step will be trying to observe these events as soon as they happen. Caltech advertised several survey possibilities related to its research: the Palomar Transient Factory, the intermediate Palomar Transient Factory that started work in February and the even more advanced Zwicky Transient Facility (ZTF) that is expected to start up in 2015.

Of course, it’s quite possible that other telescopes on the ground or orbit could work to confirm this signal.

Source: California Institute of Technology

May 4, 2013December 29, 2015 by Fraser Cain

Weekly Space Hangout – May. 3, 2013

Another busy episode of the Weekly Space Hangout, with more than a dozen space stories covered by a collection of space journalists. This week’s panel included Alan Boyle, Dr. Nicole Gugliucci, Amy Shira Teitel, David Dickinson, Dr. Matthew Francis, and Jason Major. Hosted by Fraser Cain. We discussed:

We record the Weekly Space Hangout every Friday at 12 pm Pacific / 3 pm Eastern. You can watch us live on Google+, Cosmoquest or listen after as part of the Astronomy Cast podcast feed (audio only).

May 3, 2013December 23, 2015 by Nancy Atkinson

Bright, Long-Lasting GRB Sets Energy Output Record

The maps in this animation show how the sky looks at gamma-ray energies above 100 million electron volts (MeV) with a view centered on the north galactic pole. The first frame shows the sky during a three-hour interval prior to GRB 130427A. The second frame shows a three-hour interval starting 2.5 hours before the burst, and ending 30 minutes into the event. The Fermi team chose this interval to demonstrate how bright the burst was relative to the rest of the gamma-ray sky. This burst was bright enough that Fermi autonomously left its normal surveying mode to give the LAT instrument a better view, so the three-hour exposure following the burst does not cover the whole sky in the usual way. Credit: NASA/DOE/Fermi LAT Collaboration. (Click on image if the animation is not working)

Last weekend (April 27, 2013), the Fermi and Swift spacecraft witnessed a “shockingly” bright burst of gamma rays from a dying star. Named GRB 130427A, it produced one of the longest lasting and brightest GRBs ever detected.

Because Swift was able to rapidly determine the GRB’s position in the sky, and also because of the duration and brightness of the burst, the GRB was able to be detected in optical, infrared and radio wavelengths by ground-based observatories. Astronomers quickly learned that the GRB had one other near-record breaking quality: it was relatively close, as it took place just 3.6 billion light-years away.

“This GRB is in the closest 5 percent of bursts, so the big push now is to find an emerging supernova, which accompanies nearly all long GRBs at this distance,” said Neil Gehrels, principal investigator for Swift.

Swift's X-Ray Telescope took this 0.1-second exposure of GRB 130427A at 3:50 a.m. EDT on April 27, just moments after Swift and Fermi triggered on the outburst. The image is 6.5 arcminutes across. Credit: NASA/Swift/Stefan Immler. — Swift’s X-Ray Telescope took this 0.1-second exposure of GRB 130427A at 3:50 a.m. EDT on April 27, just moments after Swift and Fermi triggered on the outburst. The image is 6.5 arcminutes across.
Credit: NASA/Swift/Stefan Immler.

“We have waited a long time for a gamma-ray burst this shockingly, eye-wateringly bright,” said Julie McEnery, project scientist for the Fermi Gamma-ray Space Telescope. “The GRB lasted so long that a record number of telescopes on the ground were able to catch it while space-based observations were still ongoing.”

No two GRBs are the same, but they are usually classified as either long or short depending on the burst’s duration. Long bursts are more common and last for between 2 seconds and several minutes; short bursts last less than 2 seconds, meaning the action can all over in only milliseconds.

This recent event started just after 3:47 a.m. EDT on April 27. Fermi’s Gamma-ray Burst Monitor (GBM) triggered on the eruption of high-energy light in the constellation Leo. The burst occurred as NASA’s Swift satellite was slewing between targets, which delayed its Burst Alert Telescope’s detection by a few seconds.

Fermi’s Large Area Telescope (LAT) recorded one gamma ray with an energy of at least 94 billion electron volts (GeV), or some 35 billion times the energy of visible light, and about three times greater than the LAT’s previous record. The GeV emission from the burst lasted for hours, and it remained detectable by the LAT for the better part of a day, setting a new record for the longest gamma-ray emission from a GRB.

The Swift BAT light curve. Credit: NASA/Swift team.

As far as the optical brightness of this event, according to a note posted on the BAUT Forum (the Universe Today and Bad Astronomy forum) data from the SARA-North 1-meter telescope at at Kitt Peak in Arizona at about 04:00 UT on April 29 showed a relative magnitude of about 18.5.

Gamma-ray bursts are the universe’s most luminous explosions, and come from the explosion of massive stars or the collision between two pulsars. Colliding pulsars are usually of short duration, so astronomers can rule out a pulsar collision as causing this event.

If the GRB is near enough, astronomers usually discover a supernova at the site a week or so after the outburst.

NASA said that ground-based observatories are monitoring the location of GRB 130427A and expect to find an underlying supernova by midmonth.

Sources: NASA, BAUTForum

May 3, 2013December 23, 2015 by Jason Major

The Rosy Remains of a Star’s Final Days

Hubble image of SNR 0519, the remains of a Type Ia supernova in the Large Magellanic Cloud

Stars like our Sun can last for a very long time (in human terms, anyway!) somewhere in the neighborhood of 10-12 billion years. Already over 4.6 billion years old, the Sun is entering middle age and will keep on happily fusing hydrogen into helium for quite some time. But eventually even stars come to the end of their lives, and their deaths are some of the most powerful — and beautiful — events in the Universe.

The wispy, glowing red structures above are the remains of a white dwarf in the neighboring Large Magellanic Cloud 150,000 light-years away. Supernova remnant SNR 0519 was created about 600 years ago (by our time) when a star like the Sun, in the final stages of its life, gathered enough material from a companion to reach a critical mass and then explode, casting its outer layers far out into space to create the cosmic rose we see today.

As the hydrogen material from the star plows outwards through interstellar space it becomes ionized, glowing bright red.

SNR 0519 is the result of a Type Ia supernova, which are the result of one white dwarf within a binary pair drawing material onto itself from the other until it undergoes a core-collapse and blows apart violently. The binary pair can be two white dwarfs or a white dwarf and another type of star, such as a red giant, but at least one white dwarf is thought to always be the progenitor.

A recent search into the heart of the remnant found no surviving post-main sequence stars, suggesting that SNR 0519 was created by two white dwarfs rather than a mismatched pair. Both stars were likely destroyed in the explosion, as any non-degenerate partner would have remained.

How Saturn’s Magnetic Activity Could Help us Pinpoint Time on the Ringed Planet

Image of Saturn’s aurora seen at ultraviolet wavelengths. The spiral shape seen here is similar to the distorted radio aurora visualised by the team and also indicates enhanced auroral activity. Credit: ESA/NASA/Hubble

He’s not even finished his first university degree yet, but Tim Kennelly is already part of a team that is altering our perception of time on Saturn.

The University of Iowa undergrad — in junior year, yet — led a paper describing activity in Saturn’s magnetosphere, where charged particles collect and sometimes form auroras. The process changes with the Saturnian seasons and could, the university stated, help scientists better understand how long a Saturn day lasts.

The researchers used information from NASA’s Cassini spacecraft, which has been orbiting the planet and its moons since 2004. The research challenge: Saturn is a gas giant full of layers that each have their own rotational speed. That makes it hard to figure out how long Saturn’s day is. (It’s about 10 hours, but varies by latitude.)

Kennelly made direct observations of seasonal changes in a phenomenon known as Saturn kilometric radiation (SKR). This robust radio signal was first discovered several decades ago and is being examined more closely by Cassini.

“UI space physicist Donald Gurnett and other scientists showed that the north and south poles have their own SKR ‘days’ that vary over periods of weeks and years,” the university stated. “How these different periods arise and are driven through the magnetosphere has become a central question of the Cassini mission, according to NASA officials.”

Kennelly observed, from looking at data collected between 2004 and 2011, that SKAs are linked with “flux tubes” that are made up of plasma, or superhot gas. These tubes happen around the same time of instances of SKAs in the northern and southern hemisphere, which changes seasonally.

It’s possible that this understanding could be carried over to other planets, the university stated, including our own.

“This finding may alter how scientists look at the Earth’s magnetosphere and the Van Allen radiation belts that affect a variety of activities at Earth ranging from space flight safety to satellite and cell phone communications,” it added.

This won’t be Kennelly’s only degree. He is about to apply to graduate schools, and he has aims to earn a doctorate in plasma physics.

“I’m pleased to have contributed to our understanding of Saturn’s magnetosphere so early in my career,” stated Kennelly. “I hope this trend continues.”

The research is described in the American Geophysical Union’s Journal of Geophysical Research.

Source: University of Iowa

May 3, 2013December 23, 2015 by John Williams

This Week’s Best Space Photos – May 3, 2013

Here’s our brand new infographic for this week’s best space images. Feel free to share and re-post!

May 3, 2013December 23, 2015 by Nancy Atkinson

How to Steer the Space Station: Chris Hadfield Explains

Shadow play of cloud and mountain at sunset, as seen from the International Space Station. Credit: NASA/CSA via Chris Hadfield.

Attitude and altitude are important factors for flying a spaceship. But How do you control the International Space Station, a ship the size of a US football field (or five hockey rinks — a better reference for Canadians!)? And where does this happen? Canadian astronaut Chris Hadfield answers these questions from inside the ISS.

And below is a beautiful image Hadfield just shared via social media today, showing shadows and clouds over a mountain:

May 3, 2013December 23, 2015 by Nancy Atkinson

A New View of Comet ISON

View of Comet ISON on May 2, 2013. Credit: Ernesto Guido & Nick Howes, Remanzacco Observatory.

Update: Here’s a brand new image of Comet C/2012 S1 ISON, as seen on May 2, 2013 by Ernesto Guido and Nick Howes of the Remanzacco Observatory (their image from May 1, which we featured earlier, is below.) For this latest image, they used the 2-meter Ritchey-Chretien Liverpool Telescope. Via Facebook, Howes said they have been able to identify almost the same tail structure which was seen in the Hubble Space Telescope images of this comet from April 10.

From the May 1 observations, their initial approximation of the tail length is around 28 arcseconds, which Howes told Universe Today is bigger than some recent reports from smaller scopes.

Below is their image from May 1, using the 2 meter La Palma Telescope:

View of Comet ISON on May 1, 2013. Credit: Ernesto Guido & Nick Howes, Remanzacco Observatory.

As of May 2, Comet ISON was approximately 3.885 AU from the Sun, which is about 581 million kilometers (361 million miles) distant from the Sun. ISON will makes its close approach to the Sun when it passes within 1.2 million km (730,000 miles) of the Sun on November 28, 2013.

Here’s a video from NASA about this comet’s path through the Solar System:

May 2, 2013December 23, 2015 by Nancy Atkinson

Astrophoto: Dramatic View of the Pipe Nebula

Image stack of Pipe Nebula Area as seen from the Pyrénées National Park in France. Credit and copyright: Martin Campbell.

This dramatic shot of the dark and shadowy Pipe Nebula has an Instagram-like feel to it. But astrophotographer Martin Campbell from France said on Flickr he has “no doubt that the pristine skies at 10,000 feet and the absence of light pollution makes it possible to produce images like this!” Campbell’s image is a two frame stack of two minute exposure time, stacked with darks and edited in Photoshop CS5. Images were taken in July 2012 in Pyrénées National Park in France. Campbell used a modified Canon 5D mkII DSLR and a Canon 85mm prime lens at F/4. Stunning!

The Pipe Nebula is part of the Ophiuchus dark cloud complex, and is also known as Barnard 59. It is located at a distance of about 600-700 light-years from Earth.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

May 2, 2013December 23, 2015 by Nancy Atkinson

Win a Blu-ray of NOVA’s “Earth From Space”

One of the most stunning compilations of satellite based images from space is a recent documentary from public television’s NOVA series, called “Earth From Space.” The show explores how satellites and spacecraft have revolutionized not only how scientists look at the world, but how they are able to understand and study its intricate systems.

“The real power of satellite observations is that they represent objective truth,” said former astronaut Piers Sellers, who is also an ecologist, and appears in the documentary. “They tell us about what the world actually is doing not what we would like to be doing, not what we might fear it to be doing, but what it’s actually doing. And it’s that that allows us to see change, real change for what it is.”

“Earth From Space” is now available in DVD and Blu-ray, and Universe Today has four copies of the Blu-ray version to give away!

In order to be entered into the giveaway drawing, just put your email address into the box at the bottom of this post (where it says “Enter the Giveaway”) before Tuesday, May 7, 2013. We’ll send you a confirmation email, so you’ll need to click that to be entered into the drawing.

Here’s a preview of the show:

The two-hour program was produced with extensive consultation with NASA scientists, and it takes data from Earth-observing satellites and transforms it into dazzling visual sequences. Each sequence exposes the intricate and surprising web of forces that sustains life on Earth. In the show, you can see how dust blown from the Sahara fertilizes the Amazon; how a vast submarine waterfall off Antarctica helps drive ocean currents around the world; and how the sun’s heating up of the southern Atlantic gives birth to a colossally powerful hurricane.

“Earth From Space” looks not only at the big picture of Earth, but also delves into the microscopic world of water molecules vaporizing over the ocean, and reveals the astonishing beauty and complexity of our dynamic planet.

“EARTH FROM SPACE” is now also available on DVD and Blu-ray for purchase. The DVD is on sale now for $19.99, with the Blu-ray priced at $24.99. The program will also be available for Digital Download. Find out more about purchasing the program here, and You can find out more info about the program itself on the PBS website.

We’re only going to use these email addresses for Universe Today giveaways/contests and announcements. We won’t be using them for any other purpose, and we definitely won’t be selling the addresses to anyone else. Once you’re on the giveaway notification list, you’ll be able to unsubscribe any time you like.