Posted on by Nancy Atkinson

Hot Dog! WISE Finds a Bounty of Black Holes

From a NASA press release:

NASA’s Wide-field Infrared Survey Explorer (WISE) mission has led to a bonanza of newfound supermassive black holes and extreme galaxies called hot DOGs, or dust-obscured galaxies.

Images from the telescope have revealed millions of dusty black hole candidates across the universe and about 1,000 even dustier objects thought to be among the brightest galaxies ever found. These powerful galaxies, which burn brightly with infrared light, are nicknamed hot DOGs.

“WISE has exposed a menagerie of hidden objects,” said Hashima Hasan, WISE program scientist at NASA Headquarters in Washington. “We’ve found an asteroid dancing ahead of Earth in its orbit, the coldest star-like orbs known and now, supermassive black holes and galaxies hiding behind cloaks of dust.”

WISE scanned the whole sky twice in infrared light, completing its survey in early 2011. Like night-vision goggles probing the dark, the telescope captured millions of images of the sky. All the data from the mission have been released publicly, allowing astronomers to dig in and make new discoveries.

The latest findings are helping astronomers better understand how galaxies and the behemoth black holes at their centers grow and evolve together. For example, the giant black hole at the center of our Milky Way galaxy, called Sagittarius A*, has 4 million times the mass of our sun and has gone through periodic feeding frenzies where material falls towards the black hole, heats up and irradiates its surroundings. Bigger central black holes, up to a billion times the mass of our sun, may even shut down star formation in galaxies.

In one study, astronomers used WISE to identify about 2.5 million actively feeding supermassive black holes across the full sky, stretching back to distances more than 10 billion light-years away. About two-thirds of these objects never had been detected before because dust blocks their visible light. WISE easily sees these monsters because their powerful, accreting black holes warm the dust, causing it to glow in infrared light.

This zoomed-in view of a portion of the all-sky survey from WISE shows a collection of quasar candidates. Image credit: NASA/JPL-Caltech/UCLA

“We’ve got the black holes cornered,” said Daniel Stern of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., lead author of the WISE black hole study and project scientist for another NASA black-hole mission, the Nuclear Spectroscopic Telescope Array (NuSTAR). “WISE is finding them across the full sky, while NuSTAR is giving us an entirely new look at their high-energy X-ray light and learning what makes them tick.”

In two other WISE papers, researchers report finding what are among the brightest galaxies known, one of the main goals of the mission. So far, they have identified about 1,000 candidates.

These extreme objects can pour out more than 100 trillion times as much light as our sun. They are so dusty, however, that they appear only in the longest wavelengths of infrared light captured by WISE. NASA’s Spitzer Space Telescope followed up on the discoveries in more detail and helped show that, in addition to hosting supermassive black holes feverishly snacking on gas and dust, these DOGs are busy churning out new stars.

“These dusty, cataclysmically forming galaxies are so rare WISE had to scan the entire sky to find them,” said Peter Eisenhardt, lead author of the paper on the first of these bright, dusty galaxies, and project scientist for WISE at JPL. “We are also seeing evidence that these record setters may have formed their black holes before the bulk of their stars. The ‘eggs’ may have come before the ‘chickens.'”

More than 100 of these objects, located about 10 billion light-years away, have been confirmed using the W.M. Keck Observatory on Mauna Kea, Hawaii, as well as the Gemini Observatory in Chile, Palomar’s 200-inch Hale telescope near San Diego, and the Multiple Mirror Telescope Observatory near Tucson, Ariz.

The WISE observations, combined with data at even longer infrared wavelengths from Caltech’s Submillimeter Observatory atop Mauna Kea, revealed that these extreme galaxies are more than twice as hot as other infrared-bright galaxies. One theory is their dust is being heated by an extremely powerful burst of activity from the supermassive black hole.

“We may be seeing a new, rare phase in the evolution of galaxies,” said Jingwen Wu of JPL, lead author of the study on the submillimeter observations. All three papers are being published in the Astrophysical Journal.

The three technical journal articles, including PDFs, can be found at http://arxiv.org/abs/1205.0811, http://arxiv.org/abs/1208.5517 and http://arxiv.org/abs/1208.5518 .

Lead image caption: With its all-sky infrared survey, NASA’s Wide-field Infrared Survey Explorer, or WISE, has identified millions of quasar candidates. Image credit: NASA/JPL-Caltech/UCLA

Posted on by Tammy Plotner

Let’s Send Neil Back To The Moon

As a native-born and life-long resident of Ohio, I have lived in the shadow of Neil Armstrong all my life. I visit Wapokenta every few years for two simple reasons – I love the Armstrong Museum and I feel a need to pass that heritage on to children, grandchildren and visiting friends. Of course, I was crushed when I read of his death. I would have given anything to have had Armstrong’s autograph on my original Apollo landing newspapers, or even just to have seen the man. He was a humble hero… and this is the quality that I loved most about him. However, Neil Armstrong and his quiet ways didn’t just impact my life. He touched us all.

“Early on Sunday morning here in Australia I got the news I never wanted to hear.” says Dave Reneke of Australia. “I was in the middle of a radio interview on a local station when they cut in with the news that Neil Armstrong had passed away. “What?? What are you telling me…Neil’s dead!!” I cut the interview short because I simply couldn’t go on.

Neil Armstrong wasn’t just an American hero; he belonged to the entire world. Kids wanted to be like him. Men looked up to him and every woman wanted to be Mrs. Neil Armstrong. My world had just collapsed and I didn’t know what to do.

A humble man who, as a kid, only ever wanted to fly, Neil went on to pilot the famous X-15 rocket plane, fly dozens of dangerous missions during the Korean War and later travel in space with Dave Scott on the Gemini 8 mission in 1966. He was unknowingly paving the way for his ultimate destiny to be the first man to walk on the Moon a mere 3 years later.

There will never be another event like this. If anything epitomises the twentieth century it was the first Moon landing. Our first steps on another world. Those of us who witnessed it remember where they were at the time, just as we did when Elvis died and Kennedy was assassinated. Tragedy imprints, indelibly!

For 12 hours during and throughout that moon walk period there was virtually no crime around the world. One in six human beings were watching the moon landing on TV, even the crims, and listening on radios. For a moment in time we were united – we knew, we just knew we were witnessing one of the greatest events in history unfold right before our very eyes.

You only get one shot at this. Only one person can walk on the moon for the first time. It took guts – the ‘right stuff!’ Neil gave them a 50/50 chance of getting to the Moon and getting back. Nasa’s odds were about the same. They were both 38 years old with families and a whole lifetime in front of them, but they went.

I was lucky enough to be invited to spend the morning with Buzz Aldrin at his home in California in 2008, prior to writing a story about the upcoming 40th anniversary of Apollo 11. I remember asking Buzz what concerned them the most, what was the one thing they were concerned about and feared the most.

Both he and Neil had two days cooped up in a small capsule to think about that. He paused, looked up and surprised me by saying they were very aware they were being watched. “We knew that everything we did and everything we said was being recorded for future history,” Buzz said. “It was on our minds constantly.”

OK, it’s over. Neil Armstrong’s name will live on from this day forward. He’s gone beyond the term legend. In the annals of history he’ll be seen as a giant, the Wilbur Wright of our time. Hundreds of years from now kids in a future classroom will be learning about Neil Armstrong, as we studied ancient history in our day.

But hang on, do we leave it all here? Is this where the story ends? Let’s do something about it, something quite radical but completely sensible. Let’s send Neil Armstrong back to the Moon! Not literally but posthumously. Let’s start a movement that will reverberate back to NASA, to the white house and engage a lobby group to have Neil Armstrong’s ashes interred on the Moon.

I’m proposing a monument to be built on the Sea Of Tranquillity, on the spot where Neil and Buzz walked and, if there’s no national burial planned, place his ashes there. An eternal symbol and testament to human accomplishment – as Neil put it, the place where men from planet Earth first set foot on the Moon, and came in peace for all mankind.

Let it be slated for the first Moon return mission, by any country or private consortium. A stone minimally inscribed with a simple message telling the story for future generations. The blood, sweat, tears and spirit of countless thousands who worked on the Moon missions would be indelibly imprinted on it. Even the words ‘Neil and Buzz were here’ would satisfy me.

We’ve got the ‘Monument to a Century of Flight’ located at the Aycock Brown Welcome Centre at milepost 1.5 in Kitty Hawk, NC, the Smithsonian cradles flight history and the ashes of people like Gene Rodenberry, James Doohan et al circle the earth in tributary gestures.

Neil’s remains would be in good company on the Moon sharing the eternal silence with the ashes of Eugene Shoemaker. If you just asked “who” Google the name, it’s a great story. Folks, this is not something we need to do, it’s something we should do!”

The author of this narrative would like to hear any feedback, especially if you’re in a position to help make this happen. Contact Dave Reneke, writer and publicist for Australasian Science magazine via his webpage www.davidreneke.com or email [email protected]

Posted on by Jason Major

Effects of Einstein’s Elusive Gravitational Waves Observed

Chandra data (above, graph) on J0806 show that its X-rays vary with a period of 321.5 seconds, or slightly more than five minutes. This implies that the X-ray source is a binary star system where two white dwarf stars are orbiting each other (above, illustration) only 50,000 miles apart, making it one of the smallest known binary orbits in the Galaxy. According to Einstein's General Theory of Relativity, such a system should produce gravitational waves - ripples in space-time - that carry energy away from the system and cause the stars to move closer together. X-ray and optical observations indicate that the orbital period of this system is decreasing by 1.2 milliseconds every year, which means that the stars are moving closer at a rate of 2 feet per year.
Potential stellar collision. Credit: Chandra

Two white dwarfs similar to those in the system SDSS J065133.338+284423.37 spiral together in this illustration from NASA. Credit: D. Berry/NASA GSFC

Locked in a spiraling orbital embrace, the super-dense remains of two dead stars are giving astronomers the evidence needed to confirm one of Einstein’s predictions about the Universe.

A binary system located about 3,000 light-years away, SDSS J065133.338+284423.37 (J0651 for short) contains two white dwarfs orbiting each other rapidly — once every 12.75 minutes. The system was discovered in April 2011, and since then astronomers have had their eyes — and four separate telescopes in locations around the world — on it to see if gravitational effects first predicted by Einstein could be seen.

According to Einstein, space-time is a structure in itself, in which all cosmic objects — planets, stars, galaxies — reside. Every object with mass puts a “dent” in this structure in all dimensions; the more massive an object, the “deeper” the dent. Light energy travels in a straight line, but when it encounters these dents it can dip in and veer off-course, an effect we see from Earth as gravitational lensing.

Einstein also predicted that exceptionally massive, rapidly rotating objects — such as a white dwarf binary pair — would create outwardly-expanding ripples in space-time that would ultimately “steal” kinetic energy from the objects themselves. These gravitational waves would be very subtle, yet in theory, observable.

Read: Astronomy Without a Telescope: Gravitational Waves

What researchers led by a team at The University of Texas at Austin have found is optical evidence of gravitational waves slowing down the stars in J0651. Originally observed in 2011 eclipsing each other (as seen from Earth) once every six minutes, the stars now eclipse six seconds sooner. This equates to a predicted orbital period reduction of about 0.25 milliseconds each year.*

“These compact stars are orbiting each other so closely that we have been able to observe the usually negligible influence of gravitational waves using a relatively simple camera on a 75-year-old telescope in just 13 months,” said study lead author J.J. Hermes, a graduate student at The University of Texas at Austin.

Based on these measurements, by April 2013 the stars will be eclipsing each other 20 seconds sooner than first observed. Eventually they will merge together entirely.

Although this isn’t “direct” observation of gravitational waves, it is evidence inferred by their predicted effects… akin to watching a floating lantern in a dark pond at night moving up and down and deducing that there are waves present.

“It’s exciting to confirm predictions Einstein made nearly a century ago by watching two stars bobbing in the wake caused by their sheer mass,” said Hermes.

As of early last year NASA and ESA had a proposed mission called LISA (Laser Interferometer Space Antenna) that would have put a series of 3 detectors into space 5 million km apart, connected by lasers. This arrangement of precision-positioned spacecraft could have detected any passing gravitational waves in the local space-time neighborhood, making direct observation possible. Sadly this mission was canceled due to FY2012 budget cuts for NASA, but ESA is moving ahead with developments for its own gravitational wave mission, called eLISA/NGO — the first “pathfinder” portion of which is slated to launch in 2014.

The study was submitted to Astrophysical Journal Letters on August 24. Read more on the McDonald Observatory news release here.

Inset image: simulation of binary black holes causing gravitational waves – C. Reisswig, L. Rezzolla (AEI); Scientific visualization – M. Koppitz (AEI & Zuse Institute Berlin)

*The difference in the eclipse time is noted as six seconds even though the orbital period decay of the two stars is only .25 milliseconds/year because of a pile-up effect of all the eclipses observed since April 2011. The measurements made by the research team takes into consideration the phase change in the J0651 system, which experiences a piling effect — similar to an out-of-sync watch — that increases relative to time^2 and is therefore a larger and easier number to detect and work with. Once that was measured, the actual orbital period decay could be figured out.

Posted on by Nancy Atkinson

Satellites Keep Track of Hurricane Isaac

This visible image of Tropical Storm Isaac taken from NOAA’s GOES-13 satellite shows the huge extent of the storm, where the eastern-most clouds lie over the Carolinas and the western-most clouds are brushing east Texas. The image was captured on Tuesday, Aug. 28, 2012 at 10:25 a.m. EDT. Image Credit: NASA GOES Project

As expected Tropical Storm Isaac has now become a full-fledged hurricane, after being fed by the warm waters in the Gulf of Mexico. The slow moving storm is now closing in on the Louisiana-Mississippi coast and could make landfall in the region seven years to the day after Hurricane Katrina devastated the same area. It is not expected to be another Katrina, but with the slowness of the storm — about 16 km/h (10 mph) — forecasters are predicting 7-14 inches of rainfall across the coast as well as inland regions, and some places could even see 20 inches. Flooding from rainfall and storm surges are expected, according to NOAA. Satellites have been keeping an eye on the storm, and above is an image from one of the GOES satellites taken on Tuesday, August 28. Below are more satellite views.

The Proba-2 satellite’s X-Cam – Exploration Camera – acquired this image at 11:38:33 GMT on August 27, 2012. Credit: ESA

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image of Isaac over the Gulf of Mexico at 2:00 p.m. CDT on August 27, 2012. Credit: NASA

Here’s a screenshot of Weather.com’s Hurricane Tracker for Isaac. Click here to see up-to-the-minute details on Isaac.

Sources: NOAA, NASA, ESA

Posted on by Jason Major

Curiosity Sends Back Incredible Hi-Res Views of Mt. Sharp

Wow — what a view! This image, released today, is a high-resolution shot of the Curiosity rover’s ultimate goal: the stratified flanks of Gale Crater’s 3.4-mile (5.5-km) high central peak, Mount Sharp. The image was taken with Curiosity’s 100mm telephoto Mastcam as a calibration test… if views like this are what we can expect from the MSL mission, all I can say is (and I’ve said it before) GO CURIOSITY!


“This is an area on Mount Sharp where Curiosity will go,” said Mastcam principal investigator Michael Malin of Malin Space Science Systems. “Those layers are our ultimate objective. The dark dune field is between us and those layers. In front of the dark sand you see redder sand, with a different composition suggested by its different color. The rocks in the foreground show diversity — some rounded, some angular, with different histories. This is a very rich geological site to look at and eventually to drive through.”

Read more: Take a Trip to Explore Gale Crater

The gravel-strewn region in the foreground is Curiosity’s immediate landing area. Then the ground dips into a low depression called a swale, then rises up again to the edge of a crater that’s rimmed with larger rocks. Quite a bit beyond that (about 2.2 miles/3.7 km away) are fields of dunes composed of darker material, and then the hummocky base of Mount Sharp itself begins to rise up about 3.4 miles (5.5 km) in the distance.

The topmost ridges of Mount Sharp visible above are actually 10 miles (16.2 km) away.

A crop of the full-size image shows a large rock at the foot of a knoll that’s about the same size as Curiosity (which is this big compared to a person and previous rovers):

The rocky mound just behind the boulder in that image is itself about 1,000 feet (300 meters) across and 300 feet (100 meters) high. Gale Crater isn’t a place for a faint-hearted rover!

The colors have been modified from the original image in order to help better discern landforms and differences in surface materials. Here, the images look more like what we’d see under natural Earthly lighting.

Curiosity already is returning more data from the Martian surface than have all of NASA’s earlier rovers combined.

“We have an international network of telecommunications relay orbiters bringing data back from Curiosity,” said JPL’s Chad Edwards, chief telecommunications engineer for NASA’s Mars Exploration Program. “Curiosity is boosting its data return by using a new capability for adjusting its transmission rate.”

See more images from Curiosity here, and keep up to date on the mission at the MSL website here.

“The knowledge we hope to gain from our observation and analysis of Gale Crater will tell us much about the possibility of life on Mars as well as the past and future possibilities for our own planet. Curiosity will bring benefits to Earth and inspire a new generation of scientists and explorers, as it prepares the way for a human mission in the not too distant future.”

– NASA Administrator Charles Bolden in a message transmitted to the Curiosity rover and then back to Earth, August 27, 2012

Images: NASA/JPL-Caltech

Posted on by Nancy Atkinson

Today’s APOD: Curiosity on Mars

Today’s Astronomy Picture of the Day (APOD) features a mosaic put together in part by Universe Today’s Ken Kremer, along with his imaging partner Marco Di Lorenzo, using images sent back from the Curiosity rover. It shows Curiosity’s landing site, Bradbury Landing, with its ultimate destination, Aeolis Mons/Mount Sharp off in the distance. It’s a beautiful and crisp image, which show parts of the rover itself — including the extended robotic arm — and its shadow on Mars. As the APOD editors Robert Nemiroff and Jerry Bonnell say, “If life ever existed on Mars it might well have been here in Gale crater, with the Curiosity rover being humanity’s current best chance to find what remains.”

Congrats to Ken and Marco for being featured on APOD!

Posted on by Nancy Atkinson

Walk on the Moon with Neil Armstrong in a Beautiful Interactive Panorama

Danish photographer Hans Nyberg has created several interactive panoramas, including a new one featuring the Curiosity rover. But today, we’d like to focus on one he created for Apollo 11, allowing you walk along with Neil Armstrong’s steps on the Moon. “Armstrong only appears in a few images on the Moon, as he was the one who took almost all images, Nyberg writes on his website. “But his shadow is there and in the helmet reflection in the famous image of Buzz Aldrin you see him.”

It works best to view the panorama in full screen; click the thumbnail images at the top to see the various still images.
Continue reading “Walk on the Moon with Neil Armstrong in a Beautiful Interactive Panorama”

Posted on by Fraser Cain

Virtual Star Party – Neil Armstrong Edition

Each week we hold a Virtual Star Party on Google+, where we connect multiple telescopes into a live Google+ Hangout and showcase the night sky. To commemorate the passing of Neil Armstrong, we focused our telescopes squarely on the Moon on Sunday, August 26th and revealed the Apollo 11 landing site.

We also turned up a beautiful view of Jupiter, Venus, the Ring Nebula, Andromeda Galaxy, Veil Nebula, the North America Nebula, and many other deep sky objects. We had a total of 6 live telescopes including Gary Gonella, Mike Chasin, Stuart Forman, David Riley, Cory Schmitz, and John Kramer. And then we were joined by live color commentary by Amy Shira Teitel, Thad Szabo, Scott Lewis, and Emily Lakdawalla.

Want to watch the next Virtual Star Party live? Just follow Fraser Cain on Google+, and you’ll see when we post the next event.

Are you an astronomer with the ability to capture images from your telescope into your computer? We’d love to have you join us for this experiment in astronomy outreach. Just email me, and I’ll help you get started.

Posted on by John Williams

Take a Trip to Explore Gale Crater

Mount Sharp Compared to Three Big Mountains on Earth

Images from the Curiosity rover on Mars are truly spectacular but a large mosaic from the THEMIS camera aboard NASA’s Mars Odyssey orbiter gives a grand perspective of our new foothold on Mars. Take some time to rove and explore Gale Crater.

The viewer, created using a web-imaging technology from Zoomify, is set to move between points of interest, such as Mars Science Laboratory’s landing site in Aeolis Palus, Glenelg, and Aeolis Mons/Mount Sharp itself. The layered sediments flanking Mount Sharp make it the primary target for Curiosity’s two-year mission. Take control at anytime by clicking on the image. This will stop the automatic roving and leave you in control to explore the terrain of Gale Crater. Use your mouse or the toolbar controls to pan and zoom around the image. You can also use the dropdown in the upper right to take you directly to certain points of interest in the image. Over time, we will add to this interactive feature as more geological points of interest are identified.

THEMIS stands for Thermal Emission Imaging System which is a multiband visible and infrared camera aboard Odyssey. The comprehensive mosaic is pieced together from 205 individual scenes, most taken recently but some dating to 2002 shortly after Odyssey entered Mars orbit in 2001. These images were taken before MSL landed on Mars. Even so, as large as the SUV-sized rover is, it would be too small to see in these images. The smallest details in this image are 18 meters or 60 feet across.

This illustration shows the size of Aoelis Mons (Mount Sharp) in comparison to three large mountains on Earth. The elevation of Mount Sharp is given in kilometers above the floor of Gale Crater. The heights of the Earth mountains are given in kilometers above sea level. Image credit: Tanya Harrison, NASA/JPL-Caltech/MSSS

Gale Crater is 154 kilometers (96 miles) wide. Near the center rises Aeolis Mons, a 5 km (3 mile) high mound of layered sediments, informally dubbed Mount Sharp, after planetary geologist Robert Sharp who died in 2004. Scientists for a time referred to the conical mountain as “The Mound.” The mountain, which would stand among the highest on Earth, cannot be seen from Earth and was unknown before planetary probes visited the Red Planet.

“The reason we decided to assemble such a large, comprehensive mosaic of Gale Crater was to give ourselves a better sense of the context around the landing site, said Jonathon Hill, a Mars research at Arizona State University who assembled the mosaic, a press release. “This will help us to better understand what Curiosity sees and measures as it roves the surface.”

Gale Crater zoom tour created by John Williams (TerraZoom) using Zoomify.

About the author: John Williams is owner of TerraZoom, a Colorado-based web development shop specializing in web mapping and online image zooms. He also writes the award-winning blog, StarryCritters, an interactive site devoted to looking at images from NASA’s Great Observatories and other sources in a different way. A former contributing editor for Final Frontier, his work has appeared in the Planetary Society Blog, Air & Space Smithsonian, Astronomy, Earth, MX Developer’s Journal, The Kansas City Star and many other newspapers and magazines.

Posted on by Jason Major

A New Species of Type Ia Supernova?

Artist’s conception of a binary star system that produces recurrent novae, and ultimately, the supernova PTF 11kx. (Credit: Romano Corradi and the Instituto de Astrofísica de Canarias)

Although they have been used as the “standard candles” of cosmic distance measurement for decades, Type Ia supernovae can result from different kinds of star systems, according to recent observations conducted by the Palomar Transient Factory team at California’s Berkeley Lab.


Judging distances across intergalactic space from here on Earth isn’t easy. Within the Milky Way — and even nearby galaxies — the light emitted by regularly pulsating stars (called Cepheid variables) can be used to determine how far away a region in space is. Outside of our own local group of galaxies, however, individual stars can’t be resolved, and so in order to figure out how far away distant galaxies are astronomers have learned to use the light from much brighter objects: Type Ia supernovae, which can flare up with a brilliance equivalent to 5 billion Suns.

Type Ia supernovae are created from a special pairing of two stars orbiting each other: one super-dense white dwarf drawing material in from a companion until a critical mass — about 40% more massive than the Sun — is reached. The overpacked white dwarf suddenly undergoes a rapid series of thermonuclear reactions, exploding in an incredibly bright outburst of material and energy… a beacon visible across the Universe.

Because the energy and luminance of Type Ia supernovae have been found to be so consistently alike, distance can be gauged by their apparent brightness as seen from Earth. The dimmer one is when observed, the farther away its galaxy is. Based on this seemingly universal similarity it’s been thought that these supernovae must be created under very similar situations… especially since none have been directly observed — until now.

An international team of astronomers working on the Palomar Transient Factory collaborative survey have observed for the first time a Type Ia supernova-creating star pair — called a progenitor system — located in the constellation Lynx. Named PTF 11kx, the system, estimated to be some 600 million light-years away, contains a white dwarf and a red giant star, a coupling that has not been seen in previous (although indirect) observations.

“It’s a total surprise to find that thermonuclear supernovae, which all seem so similar, come from different kinds of stars,” says Andy Howell, a staff scientist at the Las Cumbres Observatory Global Telescope Network (LCOGT) and a co-author on the paper, published in the August 24 issue of Science. “How could these events look so similar, if they had different origins?”

The initial observations of PTF 11kx were made possible by a robotic telescope mounted on the 48-inch Samuel Oschin Telescope at California’s Palomar Observatory as well as a high-speed data pipeline provided by the NSF, NASA and Department of Energy. The supernova was identified on January 16, 2011 and supported by subsequent spectrography data from Lick Observatory, followed up by immediate “emergency” observations with the Keck Telescope in Hawaii.

“We basically called up a fellow UC observer and interrupted their observations in order to get time critical spectra,” said Peter Nugent, a senior scientist at the Lawrence Berkeley National Laboratory and a co-author on the paper.

The Keck observations showed the PTF 11kx post-supernova system to contain slow-moving clouds of gas and dust that couldn’t have come from the recent supernova event. Instead, the clouds — which registered high in calcium in the Lick spectrographic data — must have come from a previous nova event in which the white dwarf briefly ignited and blew off an outer layer of its atmosphere. This expanding cloud was then seen to be slowing down, likely due to the stellar wind from a companion red giant.

(What’s the difference between a nova and a supernova? Read NASA’s STEREO Spots a New Nova)

Eventually the decelerating nova cloud was impacted by the rapidly-moving outburst from the supernova, evidenced by a sudden burst in the calcium signal which had gradually diminished in the two months since the January event. This calcium burst was, in effect, the supernova hitting the nova and causing it to “light up”.

The observations of PTF 11kx show that Type Ia supernova can occur in progenitor systems where the white dwarf has undergone nova eruptions, possibly repeatedly — a scenario that many astronomers had previously thought couldn’t happen. This could even mean that PTF 11kx is an entirely new species of Type Ia supernova, and while previously unseen and rare, not unique.

Which means our cosmic “standard candles” may need to get their wicks trimmed.

“We know that Type 1a supernovae vary slightly from galaxy to galaxy, and we’ve been calibrating for that, but this PTF 11kx observation is providing the first explanation of why this happens,” Nugent said. “This discovery gives us an opportunity to refine and improve the accuracy of our cosmic measurements.”

Source: Berkeley Lab news center

Inset images: PTF 11kx observation (BJ Fulton, Las Cumbres Observatory Global Telescope Network) / The 48-inch Samuel Oschin Telescope dome at Palomar Observatory. Video: Romano Corradi and the Instituto de Astrofísica de Canarias