Surprise! Classical Novae Produce Gamma Rays

by Shannon Hall on July 31, 2014

These images show Fermi data centered on each of the four gamma-ray novae observed by the LAT. Colors indicate the number of detected gamma rays with energies greater than 100 million electron volts (blue indicates lowest, yellow highest). Image Credit:  NASA/DOE/Fermi LAT Collaboration

These images show Fermi data centered on each of the four gamma-ray novae. Colors indicate the number of detected gamma rays with energies greater than 100 million electron volts (blue indicates lowest, yellow highest). Image Credit: NASA / DOE / Fermi LAT Collaboration

In a classical nova, a white dwarf siphons material off a companion star, building up a layer on its surface until the temperature and pressure are so high (a process which can take tens of thousands of years) that its hydrogen begins to undergo nuclear fusion, triggering a runaway reaction that detonates the accumulated gas.

The bright outburst, which releases up to 100,000 times the annual energy output of our Sun, can blaze for months. All the while, the white dwarf remains intact, with the potential of going nova again.

It’s a relatively straightforward picture — as far as complex astrophysics goes. But new observations with NASA’s Fermi Gamma-ray Space Telescope unexpectedly show that three classical novae — V959 Monocerotis 2012, V1324 Scorpii 2012, and V339 Delphini 2013 — and one rare nova, also produce gamma rays, the most energetic form of light.

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An artist concept image of where seven carefully-selected instruments will be located on NASA’s Mars 2020 rover. The instruments will conduct unprecedented science and exploration technology investigations on the Red Planet as never before.  Image Credit: NASA

An artist concept image of where seven carefully-selected instruments will be located on NASA’s Mars 2020 rover. The instruments will conduct unprecedented science and exploration technology investigations on the Red Planet as never before. Image Credit: NASA

NASA announced the winners of the high stakes science instrument competition to fly aboard the Mars 2020 rover at a briefing held today, Thursday, July 31, at the agency’s headquarters in Washington, D.C.

The 2020 rover’s instruments goals are to search for signs of organic molecules and past life and help pave the way for future human explorers.

Seven carefully-selected payloads were chosen from [click to continue…]

Numerous Jets Spied with New Sky Survey

by Shannon Hall on July 31, 2014

Caption: The area shown here was part of the very first image taken for the UWISH2 survey. It shows on the top a region of massive star formation (called G35.2N) with two spectacular jets. On the bottom an intermediate mass young stellar cluster (Mercer14) can be seen. Several jets are visible in its vicinity, as well as a region of photo-ionized material surrounding a young massive star. Credit: University of Kent

The area shown here was part of the very first image taken for the UWISH2 survey. Near the top is a region of massive star formation (called G35.2N) with two spectacular jets. Near the bottom is an intermediate mass young stellar cluster (Mercer14). Several jets are visible in its vicinity, as well as a region of photo-ionized material surrounding a young massive star. Image Credit: University of Kent

Jets — narrow beams of matter spat out at a high speed — typically accompany the most enigmatic astronomical objects. We see them wherever gas accretes onto compact objects, such as newborn stars or black holes. But never before have astronomers detected so many at once.

This remarkable discovery is expected to prompt significant changes in our understanding of the planetary nebulae population in the Galaxy, as well as properties of jets ejected from young forming stars.

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A model of how craters were distributed, and their relative size, on the early Earth. The circle shows the size of the impact, while the colors show when they hit our planet. Credit: Simone Marchi/SwRI

In case you need a reminder that the solar system was a harsh place to grow up, the early Earth looks like it was in the middle of a shooting gallery in this model. The map that you see above shows a scenario for where researchers believe asteroids struck our planet about four billion to 4.5 billion years ago, which is very early in the Earth’s five-billion-year history.

The research reveals the surface of the Earth repeatedly being churned by these impacts as the young solar system came together, with small rocks gradually coalescing into planetesimals. Much of the leftover debris peppered the planets, including our own.

“Prior to approximately four billion years ago, no large region of Earth’s surface could have survived untouched by impacts and their effects,” stated Simone Marchi, who led the research and works at the Southwest Research Institute in Colorado.

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New Image of Rosetta’s Comet Reveals So Much More

by Jason Major on July 31, 2014

Comet 67P/Churyumov-Gerasimenko imaged by OSIRIS on July 29, 2014

Comet 67P/Churyumov-Gerasimenko imaged by OSIRIS’ NAC on July 29, 2014

WOW! We’re really getting to the good stuff now! This is no computer-generated shape model, this is the real deal: the double-lobed nucleus of Comet 67P/C-G, as imaged by Rosetta’s OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) narrow-angle camera on Tuesday, July 29. At the time just about a week away from making its arrival, ESA’s spacecraft was 1,950 km (1,211 miles) from the comet when this image was taken. (That’s about the distance between Providence, Rhode Island and Miami, Florida… that’s one fancy zoom lens, Rosetta!)

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