Tag Archives: X-ray

AAVSO Writer’s Bureau Digest For 20 December 2013

2013dec20_aavso_logoThe AAVSO Writer’s Bureau, hosted by the American Association of Variable Star Observers (www.aavso.org), is a selective aggregator of high-quality science content for the amateur astronomer. Several astronomy bloggers, science writers, and official astronomy publishers and organizations provide articles free-of-charge for redistribution through the AAVSO-WB. The five most recent Writer’s Bureau posts are presented below with direct links to the full articles on the author’s own website. CNYO thanks the authors and the AAVSO for making these articles available for free to all astronomy groups!

Will This New Technology Transform Astronomy?

By Monica Young, Sky & Telescope

2013dec20_Arp147_341pxBack in my former life, I was an X-ray astronomer. While optical astronomy charged ahead with camera technology that benefitted from commercial investment (hello, smartphones), the X-ray detectors I worked with were of a more “homebrew” variety (really good homebrew). 

If I point an X-ray telescope at, say, a distant quasar for a few hours, I might get a few hundred photons if I’m lucky. Compare that with an optical image, where the same quasar might emit millions of photons. As a professor of mine once joked, X-rays are so few and far between, they should have names: “Look, there go Peter, Jill, and Harry.”

Read the full article at: skyandtelescope.com/news/Will-This-Cutting-Edge-Technology…

This Neutron Star Behaves Just Like The Hulk

By Elizabeth Howell, Universe Today

2013dec20_transformWhen Bruce Banner gets angry, he gets big and green and strong and well, vengeful. The Hulk is the stuff of comic book legend and as Mark Ruffalo recently showed us in The Avengers, Banner’s/Hulk’s personality can transform on a dime.

Turns out rapid transformations are the case in astronomy, too! Scientists found a peculiar neutron star that can change from radio pulsar, to X-ray pulsar, back and forth. In the Hulk’s case, a big dose of gamma rays likely fuelled his ability to transform. This star’s superpowers, however, likely come from a companion star.

Read the full article at: www.universetoday.com/105039/this-neutron-star-behaves…

Fomalhaut Star System Actually A Triple

Monica Young, Sky & Telescope

2013dec20_Fomalhaut_planet_341pxFomalhaut itself is a regular A-class star, twice the size of the Sun, accompanied by a smaller, K-class companion. The system made headlines in 2008 when astronomers discovered the controversial exoplanet candidate Fomalhaut b. Even after the dust mostly settled, the planet’s highly elliptical orbit remained unexplained.

It’s unclear whether the planet’s orbit is aligned with the far-out debris disk that rings the young star. And stranger still, the debris disk itself is off-kilter, its center offset from Fomalhaut A by 15 times the Earth-Sun distance.

Read the full article at: www.skyandtelescope.com/community/skyblog/newsblog/…

Power Of Multiple Amateur Telescopes, UNITE!

Phil Plait, Bad Astronomy

2013dec20_uniteTaking pictures of astronomical objects is a lot like collecting rainwater in buckets. Photons from your target are the rain, and your telescope is the bucket. The bigger the bucket, the more rain you collect. You get more water if you leave the bucket out longer, too.

So astronomers like to use big telescopes and long exposure times to get faint detail in their cosmic portraits. However, there’s a third option: Use more than one bucket.

Read the full article at: www.slate.com/blogs/bad_astronomy/2013/09/15/astrophoto_planetary_nebula_image_combining…

Old, Fat Stars Flicker

Mark Zastrow, Sky & Telescope

2013dec20_solar_granulation_341pxWhen you look through a telescope at a star glowing red, you might ponder: is it skinny or fat?

Although so-called red dwarfs and red giants have the same temperature, the distinction between them is profound. Red dwarfs are half the mass of the Sun or smaller. A red giant can be many times the mass of the Sun. It’s also about to die — low on energy, it’s bloated to as much as 1,500 times the radius of the Sun.

Read the full article at: skyandtelescope.com/community/skyblog/…

NASA Space Place – High-Energy Spy

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in June, 2013.

By Dr. Martin C. Weisskopf

2013february2_spaceplaceThe idea for the Chandra X-Ray Observatory was born only one year after Riccardo Giacconi discovered the first celestial X-ray source other than the Sun. In 1962, he used a sounding rocket to place the experiment above the atmosphere for a few minutes. The sounding rocket was necessary because the atmosphere blocks X-rays. If you want to look at X-ray emissions from objects like stars, galaxies, and clusters of galaxies, your instrument must get above the atmosphere.

Giacconi’s idea was to launch a large diameter (about 1 meter) telescope to bring X-rays to a focus. He wanted to investigate the hazy glow of X-rays that could be seen from all directions throughout the sounding rocket flight. He wanted to find out whether this glow was, in fact, made up of many point-like objects. That is, was the glow actually from millions of X-ray sources in the Universe. Except for the brightest sources from nearby neighbors, the rocket instrument could not distinguish objects within the glow.

Giacconi’s vision and the promise and importance of X-ray astronomy was borne out by many sounding rocket flights and, later satellite experiments, all of which provided years-, as opposed to minutes-, worth of data.

By 1980, we knew that X-ray sources exist within all classes of astronomical objects. In many cases, this discovery was completely unexpected. For example, that first source turned out to be a very small star in a binary system with a more normal star. The vast amount of energy needed to produce the X-rays was provided by gravity, which, because of the small star’s mass (about equal to the Sun’s) and compactness (about 10 km in diameter) would accelerate particles transferred from the normal star to X-ray emitting energies. In 1962, who knew such compact stars (in this case a neutron star) even existed, much less this energy transfer mechanism?

X-ray astronomy grew in importance to the fields of astronomy and astrophysics. The National Academy of Sciences, as part of its “Decadal Survey” released in 1981, recommended as its number one priority for large missions an X-ray observatory along the lines that Giacconi outlined in 1963. This observatory was eventually realized as the Chandra X-Ray Observatory, which launched in 1999.

The Chandra Project is built around a high-resolution X-ray telescope capable of sharply focusing X-rays onto two different X-ray-sensitive cameras. The focusing ability is of the caliber such that one could resolve an X-ray emitting dime at a distance of about 5 kilometers!

The building of this major scientific observatory has many stories.

2013june11_DEML50

Caption: Composite image of DEM L50, a so-called superbubble found in the Large Magellanic Cloud. X-ray data from Chandra is pink, while optical data is red, green, and blue. Superbubbles are created by winds from massive stars and the shock waves produced when the stars explode as supernovas.

Learn more about Chandra at www.science.nasa.gov/missions/chandra. Take kids on a “Trip to the Land of the Magic Windows” and see the universe in X-rays and other invisible wavelengths of light at spaceplace.nasa.gov/magic-windows.

Dr. Weisskopf is project scientist for NASA’s Chandra X-ray Observatory. This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/