Measuring tip-to-tip across its two outsized spiral arms, NGC 6872 spans more than 522,000 light-years, making it more than five times the size of our Milky Way galaxy.

“Without GALEX’s ability to detect the ultraviolet light of the youngest, hottest stars, we would never have recognized the full extent of this intriguing system,” said lead scientist Rafael Eufrasio, a research assistant at NASA’s Goddard Space Flight Center in Greenbelt, Md., who is a doctoral student at Catholic University of America in Washington. He presented the findings Thursday at the American Astronomical Society meeting in Long Beach, Calif.

The galaxy’s unusual size and appearance stem from its interaction with a much smaller disk galaxy named IC 4970, which has only about one-fifth the mass of NGC 6872. The odd couple is located 212 million light-years from Earth in the southern constellation Pavo.

Astronomers think large galaxies, including our own, grew through mergers and acquisitions — assembling over billions of years by absorbing numerous smaller systems.

Intriguingly, the gravitational interaction of NGC 6872 and IC 4970 may have done the opposite, spawning what may develop into a new small galaxy.

“The northeastern arm of NGC 6872 is the most disturbed and is rippling with star formation, but at its far end, visible only in the ultraviolet, is an object that appears to be a tidal dwarf galaxy similar to those seen in other interacting systems,” said team member Duilia de Mello, a professor of astronomy at Catholic University.

The tidal dwarf candidate is brighter in ultraviolet than other regions of the galaxy, a sign it bears a rich supply of hot young stars less than 200 million years old.

The researchers studied the galaxy across the spectrum using archival data from the European Southern Observatory’s Very Large Telescope, the Two Micron All Sky Survey, and NASA’s Spitzer Space Telescope, as well as GALEX.

By analyzing the distribution of energy by wavelength, the team uncovered a distinct pattern of stellar age along the galaxy’s two prominent spiral arms. The youngest stars appear in the far end of the northwestern arm, within the tidal dwarf candidate, and stellar ages skew progressively older toward the galaxy’s center.

The southwestern arm displays the same pattern, which is likely connected to waves of star formation triggered by the galactic encounter.

A 2007 study by Cathy Horellou at Onsala Space Observatory in Sweden and Baerbel Koribalski of the Australia National Telescope Facility developed computer simulations of the collision that reproduced the overall appearance of the system as we see it today. According to the closest match, IC 4970 made its closest approach about 130 million years ago and followed a path that took it nearly along the plane of the spiral’s disk in the same direction it rotates. The current study is consistent with this picture.

As in all barred spirals, NGC 6872 contains a stellar bar component that transitions between the spiral arms and the galaxy’s central regions. Measuring about 26,000 light-years in radius, or about twice the average length found in nearby barred spirals, it is a bar that befits a giant galaxy.

The team found no sign of recent star formation along the bar, which indicates it formed at least a few billion years ago. Its aged stars provide a fossil record of the galaxy’s stellar population before the encounter with IC 4970 stirred things up.

“Understanding the structure and dynamics of nearby interacting systems like this one brings us a step closer to placing these events into their proper cosmological context, paving the way to decoding what we find in younger, more distant systems,” said team member and Goddard astrophysicist Eli Dwek.

“The Milky Way is constantly gobbling up small galaxies and star clusters,” said Ana Bonaca, a Yale graduate student and lead author of a study forthcoming in Astrophysical Journal Letters. “The more powerful gravity of our Milky Way pulls these objects apart and their stars then become part of the Milky Way itself.”

Marla Geha, associate professor of astronomy at Yale and a co-author of the study and her team believe this latest evidence is a star cluster rather than of a larger galaxy.  She says: “Our discovery is more of a light snack than a big meal for the Milky Way,” says. “Studying this digestion process in detail is important because it gives us new insight into how all galaxies form and evolve.”

It would be interesting to be here in about 3 billion years with the Milky Way and Andromeda galaxies run into one another.  The results could look like this:

or this

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- Ex astris, scientia -

I am and avid amateur astronomer and intellectual property attorney.  As a former Chief Petty Officer in the U.S. Navy, I am a proud member of the Armed Service Committee of the Los Angeles County Bar Association working to aid all active duty and veterans in our communities.  Connect with me on Google +

Norman

The Helix Nebula (also known as NGC 7293) represents a dying star known as a planetary nebula.  Planetary nebulas aren’t planets at all, but they were first identified and named in the 18th century because they resembled gas giants like Jupiter and Saturn, and the name stuck.

The new picture combines data from the Spitzer Space Telescope, which takes images in the infrared (the yellow part of the image), and the Galaxy Evolution Explorer (GALEX), that images in ultraviolet (the blue part of the image) on the opposite side of the electromagnetic spectrum.

The Helix Nebula is about 650 light-years from Earth in the constellation of Aquarius.   The nebula is classified as a planetary nebula.   Stars about the size of the sun, at the end of their lives, run out of hydrogen and helium fuel for fusion in their cores.  When this happens, the stars begin to expel their outer gaseous layers into glowing remnants around them.  When all the gas has been expelled, the stars collapse into a white dwarf star about the size of the Earth.

“The white dwarf is about the size of Earth, but has a mass very close to that of the original star; in fact, a teaspoon of a white dwarf would weigh as much as a few elephants!” NASA scientists stated.

The white dwarf star in the Helix nebula is the tiny white dot in the center.

If you need help with a patent, copyright or trademark matter, or know someone that can use my help, please contact me for a free 30 minute consultation at nvantreeck@usip.com or call TOLL FREE at 1-855-UR IDEAS (1-855-874-3327) and ask for Norman.

- Ex astris, scientia -

I am and avid amateur astronomer and intellectual property attorney.  As a former Chief Petty Officer in the U.S. Navy, I am a proud member of the Armed Service Committee of the Los Angeles County Bar Association working to aid all active duty and veterans in our communities.  Connect with me on Google +

Norman

Helix Nebula

News sources report that a pair of NASA space telescopes have captured a spectacular new photo of the Helix Nebula, a glowing celestial vision that resembles a giant cosmic eye.

Cosmic Eye? More like Wadjet Eye. The Helix Nebula (also known as NGC 7293) represents a dying star known as a planetary nebula.

The new picture, released Wednesday (Oct. 3), combines data from NASA’s Spitzer Space Telescope, which observes in long-wavelength infrared light, and the Galaxy Evolution Explorer (GALEX), which picked out the short-wavelength ultraviolet light coming from the object.

The Helix Nebula is located about 650 light-years from Earth in the constellation of Aquarius. It provides a sneak peak at the future of our own sun, which is expected to turn into a planetary nebula in about 5 billion years.

Planetary nebulas are stars around the size of the sun that have neared the ends of their lives and run out of hydrogen and helium fuel for fusion in their cores. At this point, they puff out their outer gaseous layers into glowing shells around them, and condense into small white dwarf stars.

Of course this is the mundane explanation from CBS online. For the mythical one check out Written in The Sky~ Rise of the Wadjet Witch.

WW

Image Credit: NASA

Planets Under a Red Sun

This artist’s concept illustrates a young, red dwarf star surrounded by three planets. Such stars are dimmer and smaller than yellow stars like our sun, which makes them ideal targets for astronomers wishing to take images of planets outside our solar system, called exoplanets. NASA’s Galaxy Evolution Explorer is helping to identify young, red dwarf stars that are close to us by detecting their ultraviolet light (stars give off a lot of ultraviolet light in their youth)

Supermassive black holes lurk at the centre of almost every galaxy, weighing billions of times more than our Sun – and Nasa has just caught sight of one ‘feeding’ on a star.

A re giant star that wandered too close to the centre of a galaxy 2.7 billion light years away was pulled in by the enormous gravity of the black hole – and shredded.

It’s the first time an observatory has seen a known star ripped apart in this way.

(via: NASA)

Posted by Synlah for Roqoo Depot

This ultraviolet image of the Cygnus Loop Nebula was taken by NASA’s Galaxy Evolution Explorer. The Cygnus Loop extends across an area more than three times the size of the full moon in the night sky and is tucked next to one of the “wings” in the constellation of Cygnus the Swan.

Image Credit: NASA

A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at accelerating speeds. 

The survey used data from NASA’s space-based Galaxy Evolution Explorer and the Anglo-Australian Telescope on Siding Spring Mountain in Australia.

The findings offer new support for the favored theory of how dark energy works — as a constant force, uniformly affecting the universe and propelling its runaway expansion. They contradict an alternate theory, where gravity, not dark energy, is the force pushing space apart. According to this alternate theory, with which the new survey results are not consistent, Albert Einstein’s concept of gravity is wrong, and gravity becomes repulsive instead of attractive when acting at great distances.