Hubble Sees Dazzling Dust in the Iris Nebula

NGC 7023. Credit: NASA and ESA

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Another gorgeous image from Hubble! This close-up of NGC 7023, or the Iris Nebula, shows an area filled with cosmic dust. Illuminated from above by the nearby star HD 200775, the dust resembles pink cotton candy, accentuated with diamond-like stars. The “cotton candy” is actually made up of tiny particles of solid matter, with sizes from ten to a hundred times smaller than those of the dust grains we find on Earth, and the “diamonds” are both background and foreground stars.

The image was taken previous to Hubble’s recent servicing mission, using the Advanced Camera for Surveys. Astronomers also used Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument to try to determine which chemical elements are present in the nebula.

NGC 7023 is a reflection nebula, which means it scatters light from the massive nearby star. Reflection nebulae are different from emission nebulae, which are clouds of gas that are hot enough to emit light themselves. Reflection nebulae tend to appear blue because of the way light scatters, but parts of the Iris Nebula appear unusually red-ish or pink.

See more, including a movie pan of the nebula here.

Carnival of Space #131

This week’s Carnival of Space is hosted by John Williams over at Starry Critters

Click here to read the Carnival of Space #131.

And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.

Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.

dotAstronomy Conference

I’m attending the .Astronomy (dotAstronomy) Conference this week Leiden, The Netherlands, where we are discussing novel concepts of thinking and working in astronomy today. We’ll be discussing the data deluge that will be produced by upcoming surveys and instruments, how citizen science is making a real impact, and the new ways of communicating science to the public with web 2.0, blogs, podcasts and social networking. All week, you can watch the morning sessions of .Astronomy online at UStream, (or watch the stream below) and check out the .Astronomy website here to see what talks you are interested in. You can ask questions via the UStream chat, or follow along with the .Astronomy Twitter feed. I’ll be giving a talk on the 365 Days of Astronomy on Friday morning.

Live video by Ustream

Podcast: Edwin Hubble

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You might know the name “Hubble” because of the Hubble Space Telescope. But this phenomenal observatory was named after one of the most influential astronomers in modern history. Hubble discovered that galaxies are speeding away from us in all directions, leading to our current understanding of an expanding Universe. Let’s learn about the man behind the telescope.

Click here to download the episode.
Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Edwin Hubble show notes and transcript.

Podcast: Launch Facilities

Launching a rocket into space requires a big effort on the ground. Space agencies have built up huge infrastructures to store, prepare and launch rockets. Let’s take a look at what’s involved on the ground at a place like Cape Canaveral. What happens before, during and after a launch.

Click here to download the episode.

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

Launch Facilities show notes and transcript.

Shuttle Atlantis Returns Home (Video)


Space shuttle Atlantis and its crew of seven astronauts landed safely at Kennedy Space Center Friday morning at 9:44 a.m. EST, ending an 11-day journey to the ISS. The Atlantis shuttle flew 171 orbits around Earth and traveled 7,226,176 kilometers (4,490,138 miles) since its Nov. 16 launch. STS-129 was the 129th space shuttle mission, the 31st for Atlantis and the 31st shuttle mission to the International Space Station. It was the fifth and final flight of 2009. Enjoy the landing video!

Fermi Finds Gamma-Ray Microquasar

Fermi’s Large Area Telescope has detected bursts of gamma-rays in the binary system Cygnus X-3, which astronomers say are coming from a microquasar. While microquasars have strong emissions across is a broad range of wavelengths, this is the first time this type of object has been detected in gamma rays. “Cygnus X-3 is a genuine microquasar and it’s the first for which we can prove high-energy gamma-ray emission,” said Stéphane Corbel at Paris Diderot University in France.

n Cygnus X-3, an accretion disk surrounding a black hole or neutron star orbits close to a hot, massive star. Gamma rays (purple, in this illustration) likely arise when fast-moving electrons above and below the disk collide with the star's ultraviolet light. Fermi sees more of this emission when the disk is on the far side of its orbit. Credit: NASA's Goddard Space Flight Center
n Cygnus X-3, an accretion disk surrounding a black hole or neutron star orbits close to a hot, massive star. Gamma rays (purple, in this illustration) likely arise when fast-moving electrons above and below the disk collide with the star's ultraviolet light. Fermi sees more of this emission when the disk is on the far side of its orbit. Credit: NASA's Goddard Space Flight Center

Microquasars are stellar mass object that displays in miniature some of the properties of quasars: a normal star begins shedding its matter onto either a neutron star or a black hole. This phenomenon produces large amounts of radiation and “jets” of material moving at relativistic speeds—more than 10% the speed of light—away from the star. These “relativistic jets” are a great mystery that astronomers are still trying to understand, but this new gamma-ray microquasar could provide new ways to study them.

At the center of Cygnus X-3 lies a massive Wolf-Rayet star. With a surface temperature of 100,255.372 Kelvin (180,000 degrees F,) or about 17 times hotter than the sun, the star is so hot that its mass bleeds into space in the form of a powerful outflow called a stellar wind. “In just 100,000 years, this fast, dense wind removes as much mass from the Wolf-Rayet star as our sun contains,” said Robin Corbet at the University of Maryland, Baltimore County.

The researchers matched the gamma-rays to the known orbital period of the Cygnus X-3 microquasar in order to confirm that the strong pulses of radiation were, in fact, originating from the object. They also matched the gamma-rays with radio emission from the relativistic jets of Cygnus X-3.

Brighter colors indicate greater numbers of gamma rays detected in this Fermi LAT view of a region centered on the position of Cygnus X-3 (circled). The brightest sources are pulsars. Credit: NASA/DOE/Fermi LAT Collaboration
Brighter colors indicate greater numbers of gamma rays detected in this Fermi LAT view of a region centered on the position of Cygnus X-3 (circled). The brightest sources are pulsars. Credit: NASA/DOE/Fermi LAT Collaboration

Every 4.8 hours, a compact companion embedded in a disk of hot gas wheels around the star. “This object is most likely a black hole, but we can’t yet rule out a neutron star,” Corbet said.

Between Oct. 11 and Dec. 20, 2008, and again between June 8 and Aug. 2, 2009, Cygnus X-3 was unusually active. The team found that outbursts in the system’s gamma-ray emission preceded flaring in the radio jet by roughly five days, strongly suggesting a relationship between the two.

These new findings should provide more information about the formation of such mysterious and fast-moving relativistic jets. This research appears in the 26 November issue of Science Express.

Read the team’s abstract

Sources: Science, Goddard Spaceflight Center

Absolutely Amazing Shuttle Ascent Video


This video compilation of the STS-129 ascent is incredible! (and is it now available again after a short hiatus.) It includes video highlights from ground, air, SRB and external tank cameras during the launch of Atlantis on Nov. 16, 2009. It will give you a new appreciation for the space shuttle. The music is great, as well. Not to be missed!
Continue reading “Absolutely Amazing Shuttle Ascent Video”

Where In The Universe Challenge, Thanksgiving Edition

Here’s this week’s image for the WITU Challenge, to test your visual knowledge of the cosmos. You know what to do: take a look at this image and see if you can determine where in the universe this image is from; give yourself extra points if you can name the instrument responsible for the image. We’ll provide the image today, but won’t reveal the answer until tomorrow. This gives you a chance to mull over the image and provide your answer/guess in the comment section. Please, no links or extensive explanations of what you think this is — give everyone the chance to guess. Best wishes to everyone celebrating Thanksgiving, no matter where you are!

UPDATE: The answer is now posted below.

This is the Trifid Nebula, as seen by the Gemini Telescope. This observation was done as a result of an essay contest for elementary school children, and the winner, Ingrid Braul from British Columbia, Canada, wrote: “I think the Trifid Nebula is the most beautiful thing in the whole universe. It’s really pretty with all the colours in it. When I look at it closely, I think of it as a majestic cloud of creation. It makes me think of the beginning of time, and how our solar system started.”

She sure got that right! Read more about the essay contest and see Ingrid’s entire essay here.

Astronomers Dig Up Relic of the Milky Way’s Central Bulge

Terzan 5. Credit: ESO/F. Ferraro

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Like archaeologists who dig through the layers of dirt to unearth crucial pieces of the history of mankind, astronomers have been gazing through the thick layers of interstellar dust obscuring the central bulge of the Milky Way and have unveiled an extraordinary cosmic relic. Within the bulge is an unusual mix of stars in the stellar grouping known as Terzan 5, and such a mix has never been observed anywhere in the bulge before. This peculiar conglomeration of stars suggests that Terzan 5 is one of the bulge’s primordial building blocks, most likely the relic of a dwarf galaxy that merged with the Milky Way during its very early days.

The new observations of Terzan 5 show that this object, unlike all but a few exceptional globular clusters, does not harbor stars which are all born at the same time — what astronomers call a “single population” of stars. Instead, the multitude of glowing stars in Terzan 5 formed in at least two different epochs, the earliest probably some 12 billion years ago and then again 6 billion years ago.

Dust around Terzan 5. Credit: ESO
Dust around Terzan 5. Credit: ESO

“Only one globular cluster with such a complex history of star formation has been observed in the halo of the Milky Way: Omega Centauri,” says team member Emanuele Dalessandro. “This is the first time we see this in the bulge.”

Using ESO’s Very Large Telescope, equipped with the Multi-conjugate Adaptive Optics Demonstrator (MAD), the astronomers were able to “disperse the fog” of the dust clouds in the central bulge to reveal the myriad of stars.

Through the sharp eye of the VLT, the astronomers also found that Terzan 5 is more massive than previously thought: along with the complex composition and troubled star formation history of the system, this suggests that it might be the surviving remnant of a disrupted dwarf galaxy, which merged with the Milky Way during its very early stages and thus contributed to form the galactic bulge.

The team hopes this is only the first in a series of discoveries on the origin of bulges in galaxies.

“The history of the Milky Way is encoded in its oldest fragments, globular clusters and other systems of stars that have witnessed the entire evolution of our galaxy,” says Francesco Ferraro, lead author of a paper appearing in this week’s issue of the journal Nature. “Our new study opens a new window on yet another piece of our galactic past.”

Source: ESO