Category: Astronomy

I’ll be attending the American Astronomical Society/Astronomy Society of the Pacific Meeting in St. Louis for the next few days, starting Saturday, May 31 with some educational workshops and symposiums, and then Monday-Thursday is the AAS conference. This will be my first conference as a journalist, and I’m looking forward to being overwhelmed and star-struck.

If you’ll be there, or if you happen to be in the St. Louis area, we are planning a “Astroblogger Meet-Up” on Tuesday, June 3 at 7:00 pm at KitchenK bar & restaurant. The big names who will be there: Pamela Gay from Astronomy Cast and Star Stryder, Phil Plait from Bad Astronomy, Chris Lintott from Chris Lintott’s Universe and Galaxy Zoo, and Tammy Plotner and me (Nancy) from Universe Today, and more. Please join us if you can!

If you can’t be in St. Louis, we’ll try to bring the conference to you via reports and articles here on UT and liveblogging on Astronomy Cast Live.

Spitzer Space Telescope Image of Magnetar SGR 1900+14

If only it were closer to Halloween. NASA’s Spitzer Space Telescope has captured an infrared image showing a ghostly ring extending seven light-years across around the corpse of a massive star, called a magnetar . The collapsed star, called Magnetar SGR 1900+14, is unlike anything ever seen before. Scientists believe this object may have formed in 1998 when the magnetar erupted in a giant flare. They believe the crusty surface of the magnetar cracked, sending out a flare, or blast of energy, that excavated a nearby cloud of dust, leaving an outer, dusty ring. “The universe is a big place and weird things can happen,” said Stefanie Wachter of NASA’s Spitzer Science Center.

Wachter is lead author of a paper about the findings in this week’s Nature. The ring is oblong, with dimensions of about seven by three light-years. It appears to be flat, or two-dimensional, but the scientists said they can’t rule out the possibility of a three-dimensional shell.

Magnetars are formed when a giant star ends its life in a supernova explosion, leaving behind a super dense neutron star with an incredibly strong magnetic field. These are the cores of massive stars that blew up in supernova explosions, but unlike other dead stars, they slowly pulsate with X-rays and have tremendously strong magnetic fields. The ring seen by Spitzer could not have formed during the original explosion, as any material as close to the star as the ring would have been disrupted by the supernova shock wave.

This composite image was taken using all three of Spitzer’s science instruments. The blue color represents 3.6-micron infrared light taken by the infrared array camera, green is 16-micron light from the infrared spectograph, and red is 24-micron radiation from the multiband imaging photometer.

Original News Source: NASA

I hope you’re not tired of seeing HiRISE images of Phoenix, but this one shows the grandeur of Mars compared to the tininess of our spacecraft. Remember the close-up image of Phoenix descending to Mars’ surface with its parachute? Well, the HiRISE folks were holding back on us. Above is the jaw-dropping full image, with the inset being the close-up of Phoenix! What an amazing vista, and our little Phoenix is just a tiny pixel or two in the entire image. That the imaging team found Phoenix in this photo is incredible. And no, Phoenix is not heading into the crater, as it appears. The lander is actually about 20 kilometers (about 12 miles) in front of the crater. This is just so amazing.

Tell me when you’ve had enough of these images, but I’m saying, “Keep ’em coming!”

I love HiRISE even more.

BTW, the crater is informally called “Heimdall,” and is about 10 km (6 miles) wide.

Original Source: JPL Phoenix News

For the first time, a team of astronomers has taken a close-up image of an individual dying supergiant star, WHO G64, in a neighboring galaxy, the Large Magellanic Cloud, about 160,000 light years distant. Researchers have been trying for decades to look closely at how aging stars lose a considerable amount of their mass before they go supernova. But this is difficult because of the great distances. However, by combining two 8.2m telescopes in Chile as an interferometer, they achieved the resolving power of a 60-m telescope. With this super-sharp view, they discovered that the dying supergiant star is developing a thick dust torus around it. They estimated that the star had an initial mass of about 25 times the mass of our sun. But now, the star is shedding material so rapidly that it has already lost 10 – 40% of its initial mass and is speeding toward its final fate as a supernova.

When a star becomes older, it ejects a huge amount of material and gets embedded in a thick envelope, in which a variety of molecules and dust form. Even with the world’s largest optical telescopes with 8 – 10m diameters, it is still difficult to take a close-up shot of aging stars closest to Earth, let alone those outside our own galaxy, the Milky Way.

Using two or more telescopes combined as an “interferometer” provides a way to achieve much higher resolving power than an individual telescope alone. The ESO’s Very Large Telescope Interferometer (VLTI) in Chile is one of the largest interferometers, combining two or three 8.2m telescopes. A team of researchers at Max Planck Institute for Radio Astronomy (MPIfR) and the European Southern Observatory (ESO) these instruments at mid-infrared wavelengths, which is ideal for observing the thermal radiation from the dust envelope heated by the star.

“For the first time we could take a close-up view of an individual star outside our Galaxy, and this is an important first step to understand how dying stars in other galaxies differ from their counterparts in our Milky Way”, says Keiichi Ohnaka at the MPIfR. “We discovered that the dying supergiant star WOH G64 is surrounded by a thick dust torus which sort of looks like a thick bagel by comparing it with detailed theoretical modeling.” The diameter of the supergiant star is as large as the orbit of Saturn in the solar system. The dimensions of the whole torus are considerably larger: the inner edge of the torus is at 120 AU (“Astronomical Units”, corresponding to the distance of the Earth from the sun), the total size of the torus reaches almost one light year.

In the next few thousand or ten thousand years, WHO G64 will explode as a supernova. Judging from its mass of WOH G64, it will become visible to the unaided eye in the southern hemisphere. The supernova explosion will blow away most of the mass of WOH G64, which will then be recycled as the building blocks for stars of the next generation.

Original News Source: Max Plank Institute

The Mars Reconnaissance Orbiter did some first class reconnaissance by snapping an image of Phoenix during its descent with a parachute. This is the first time that a spacecraft has imaged the final descent of another spacecraft onto a planetary body. The incredible HiRISE Camera was pointed towards the area of Phoenix’s descent, and from a distance of about 760 kilometers (472 miles) above the surface of the Red Planet, it captured Phoenix with its parachute descending through the Martian atmosphere. The image reveals an apparent 10-meter-wide (30-foot-wide) parachute fully inflated. Absolutely amazing.

Also, JPL has a couple of new videos of interest for Phoenix. If you want to re-live the drama of the landing, here a great video showing the events in mission control along with the artist’s conception video of the events taking place on Mars. It’s great fun.

Also, here’s another video that describes the scientific endeavors that Phoenix will be undertaking.

More about the MRO image capturing the descent:
The image faintly detects the chords attaching the backshell and parachute. The surroundings look dark, but correspond to the fully illuminated Martian surface, which is much darker than the parachute and backshell.

Phoenix released its parachute at an altitude of about 12.6 kilometers (7.8 miles) and a velocity of 1.7 times the speed of sound.

The HiRISE acquired this image on May 25, 2008, at 7:36 p.m. Eastern Time. It is a highly oblique view of the Martian surface, 26 degrees above the horizon, or 64 degrees from the normal straight-down imaging of Mars Reconnaissance Orbiter. The image has a scale of 0.76 meters per pixel.

Here are a couple of colorized images of Phoenix’s first views of its landing site. They are a little more exciting than the black and white version, and the human eye can pick out more detail in color. This is an approximate-color image taken shortly after landing by the Phoenix’s Surface Stereo Imager, generated from two color filters, a violet and an infrared filter. It shows the vast plains of the northern polar region of Mars. The flat landscape is strewn with tiny pebbles and shows polygonal cracking, a pattern seen widely in Martian high latitudes and also observed in permafrost terrains on Earth. The polygonal cracking is believed to have resulted from seasonal freezing and thawing of surface ice.

Phoenix touched down on the Red Planet at 7:53 EDT yesterday in an arctic region called Vastitas Borealis, at 68 degrees north latitude, 234 degrees east longitude.

Polygonal cracks are visible in this close up image of the Mars arctic tundra. This color version was again generated using one of the first black and white image sent by Phoenix and processed with two color filters. The SSI camera on Phoenix will be calibrated with colors on the spacecraft itself in order to make sure the color images it sends back will show the “real” colors on Mars as close as possible. SSI has a 12-position color filter that ranges from optical to infrared.

Phoenix’s approximate position on Mars is shown here. The red circle on the far right of the blue landing elipse is where the spacecraft is estimated to be. At the time this post is written, the Mars Reconnaissance Orbiter has probably already passed over this area on Mars and will attempt to image the lander on the surface of Mars. We’ll post that if the MRO team is successful in this difficult effort.

News Source: NASA